The Psychology of Ageing - An Intro. 3rd ed. - I. Stuart-Hamilton (Jessica Kingsley, 2000) WW
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The Psychology of Ageing

An Introduction

3rd edition
of related interest

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Hearing the Voice of People with Dementia

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Spirituality and Ageing

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ISBN 1 85302 631 X

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The Psychology of Ageing

3rd edition

An Introduction

Ian Stuart-Hamilton

Jessica Kingsley Publishers

London and Philadelphia

All rights reserved. No paragraph of this publication may be reproduced, copied or transmitted save with written permission of the Copyright Act 1956 (as amended), or under the terms of any licence permitting limited copying issued by the Copyright Li-censing Agency, 33–34 Alfred Place, London WC1E 7DP. Any person who does any unauthorised act in relation to this publication may be liable to prosecution and civil claims for damages.

The right of Ian Stuart-Hamilton to be identified as author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.

First edition published in the United Kingdom in 1991

Second edition published in the United Kingdom in 1994

This edition published in the United Kingdom in 2000 by Jessica Kingsley Publishers Ltd,

116 Pentonville Road, London

N1 9JB, England
and

325 Chestnut Street,

Philadelphia PA 19106, USA.

www.jkp.com

© Copyright 2000 Ian Stuart-Hamilton

Library of Congress Cataloging in Publication Data A CIP Catalog record for this book is available from the Library of Congress British Library Cataloguing in Publication Data

A CIP Catalogue record for this book is available from the British Library ISBN 1 85302 771 5

Printed and Bound in Great Britain by

Athenaeum Press, Gateshead, Tyne and Wear

Contents

Introduction

1.

What is Ageing?

The greying population

Differences in life expectancy

Definitions of ageing

Biological ageing

The ageing body

The ageing sensory systems

Vision

Hearing

Other senses

Overview

Basic anatomy of the nervous system

The neuron

Anatomy of the nervous system

PNS anatomy

CNS anatomy

Neuronal changes in later life

Summary and overview

Suggested further reading

2.

Measuring Intellectual Change in Later Life

Intuitive beliefs about ageing and intelligence

Crystallised and fluid intelligence

Age changes in general intelligence (g)

Age changes in fluid and crystallised intelligence

Wisdom

Individual variation

The terminal drop model

Disuse theory

Reaction times

Other physical correlations with intellectual skills Intelligence level and its relationship with specific intellectual skills Attentional deficits in ageing

Conceptual organisation

Creativity in later life

Piagetian conservation

Summary

Suggested further reading

3.

Ageing and Memory

Introduction

Ageing and short-term memory (STM)

Ageing and long-term memory (LTM)

Remote memory

Eyewitness testimony

Text recall

Semantic memory

Implicit memory

Autobiographical memory and ageing

Prospective memory

Metamemory and ageing

Summary and overview — how does ageing affect memory?

Suggested reading

4.

Ageing and Language

Introduction

The role of reading in people’s lifestyles

Physiological constraints

Word recognition

Syntactic processing

Story comprehension

General aspects

Choice of participants

Choice of presentation of materials

Interaction between subject type and reading materials Ecological validity

Summary

Recommended reading

5.

Ageing, Personality and Lifestyle

Introduction

Trait models

Psychoanalytic theory and the ageing personality

Other personality type studies

Images of ageing and life satisfaction in later life General changes

Causes of change in image

Work and retirement

Widowhood

Other factors

Personality and health

Marriage

Sexuality and ageing

Preferences for lifestyle

The role of the family

Cross-cultural differences in ageing

Summary

Recommended reading

6.

Mental Illness and Ageing

Introduction

Dementia

Introduction

Classifying dementias

Dementia of the Alzheimer Type (DAT)

Vascular dementia (VaD)

Other dementias

Creutzfeldt-Jakob Disease (CJD)

Huntington’s disease

Cortical and subcortical dementias

Illnesses which can be confused with dementia

Problems with diagnosis and testing

Memory changes in dementia

Linguistic skills and semantic processes

Visuo-spatial skills

Olfaction

The effect on caregivers

Summary

Depression

Anxiety

Substance abuse

Personality disorder

Schizophrenia

Overview

7.

Problems in Measuring the Psychological Status of Older People Introduction

The view from without

Confounding variables and the search for ‘pure’ ageing The relevance of findings to everyday life

Unwitting ageism

8.

What is the Future of Ageing?

Introduction

What will constitute being ‘old’?

Older people and the technological society

Conclusion

Glossary of Technical Terms

References

Acknowledgements

I wish to thank Alison Windsor who very helpfully compiled some of the initial journal searches for sections of this book. Gratitude of course to my wife, Ruth, who typed up the Glossary, and as always has been a bedrock of support throughout. Finally, I offer my usual thanks to my colleagues at UCW, particularly Dorma Urwin, Hilary Emery, and Jan Francis-Smythe.

To CMOTD

‘the satirical rogue says here that old men have grey beards, that their faces are wrinkled, their eyes purging thick amber and plumtree gum, and that they have a plentiful lack of wit, together with the most weak hams. All which sir, though I most powerfully and potently believe, yet I hold it not honesty to have it thus set down.’

Hamlet, Act 2, Sc ii

Introduction

The second edition of this book appeared three years after the first; this third edition has taken considerably more than double this interval to appear. During this time, both I and the institution where I work have changed their titles, and a lot of research papers have been produced. In part the delay is due to other writing projects (in particular four other textbooks under my sole authorship and a jointly edited work) and also because for some time I felt no particular need to update what I had written. This was not because new work was not being produced (far from it), but the general tale which psychogerontology had to tell was not altering particularly drastically. However, after a certain point, even the same house needs a new coat of paint, and if nothing else, more modern experimental proofs of the same arguments were needed. I have thus, where appropriate, updated the book in this manner. I have done more than this, however.

First, I have introduced new topics where I felt there was a need, though I have not introduced every single area of research in psychogerontology, simply because there is not room in a relatively compact book. Second, I have completely rewritten large sections of some chapters. In part this was for aesthetic reasons, but a more pressing reason was because I felt that some chapters were better presented in a different format. For example, Chapter 6, which in previous editions was solely devoted to dementia, is now on mental illness in later life (though dementia takes the lion’s share of the words). Critics have been almost universally generous in their praise for the previous editions (for which, my baffled thanks) but a question raised on more than one occasion was why was there not more on mental illness in general. The simple reason was that I had originally intended the book for a readership whom I expected to be uninterested in the topic. However, as the book has become a set text for some clinical psychology courses and similar, I felt it appropriate to offer at least a to-ken nod in this direction. I have also expanded what was the final chapter of earlier editions and divided it into two separate chapters: the first is on rather more advanced critiques of experimental methods, whilst the second is a look forward to future features of ageing. The main body of the text is intended to be a relatively impartial in-11

12 / THE PSYCHOLOGY OF AGEING
troduction to psychogerontology, whilst these final chapters are in effect critical essays on contrasting aspects of psychogerontology intended as the starting points for discussions.

A final change to mention is that in line with recent practice in some (though not all) quarters of my profession, I have tried to avoid the use of ‘the elderly’ and similar phrases. These were never intended to be pejorative in earlier editions (and I doubt if they were perceived as such) but being mindful of changing conventions, I feel it is appropriate to change my usage.

Other aspects of the book have been retained, however. The glossary of technical terms, which has proved popular, has been expanded (it is essentially composed of the psychogerontological entries from my Dictionary of Developmental Psychology, by the same publisher as this text). I have also tried where possible to give a judicious mix of references. Thus, as well as more specialised journal articles (which some readers may find hard to locate) I have also included more general textbooks.

Professor Ian Stuart-Hamilton

University College Worcester

January 2000
chapter 1

What is Ageing?

The greying population

Ageing is not unique to modern times, but it is only in the past hundred years that it has become commonplace. It is estimated that in prehistoric times, old age was extremely rare, and even up to the seventeenth century, probably only about one per cent of the population was over 65. By the nineteenth century, this proportion had risen to approximately four per cent (Cowgill, 1970). In Britain today, about 11
million people, or 18 per cent of the population are over pensionable age (HMSO, 1998), and this figure is expected to rise until it peaks at approximately 14 million in 2040, before changing birth rates will cause a relative decline. Similar proportions and growth are predicted for other industrialised nations (OECD, 1988). To take another perspective, about 70 per cent of today’s western population will live past 65, and 30-40 per cent past 80 (possibly more if actuarial tables being developed at the time of writing prove correct). In 1900, only about 25 per cent of the population could even hope to reach their 65th birthday (Brody, 1988). Or, put yet another way, the average life expectancy of a baby born in 1900 was 47–55 years; today that figure is at least 30 years more than this (OECD, 1988). Arising from these considerations, the modern industrialised population has been described as a rectangular society. Since roughly equal numbers of people are alive in each age decade (i.e. equal numbers of 0–9 year-olds, 10–19 year-olds, etc), a histogram plotting numbers alive against age decade appears (with a little artistic licence) like a rectangle. By comparison, a graph from 1900 looks like a pyramid (lots of people in the youngest age decade, progressively fewer in the older ones), and hence is described as a pyramidal society.

However, without caveats, the above figures are misleading. To the casual reader, the information that in 1900 life expectancy was in the mid-fifties implies that 13

14 / THE PSYCHOLOGY OF AGEING
everyone died before they reached 60, which is palpably nonsense. Life expectancy refers to the age by which half of a group of people born in the same period of time die. In other words, half the age group live longer than this (the members of a group who are left alive at any point are called the survivors). The reason for the lower life expectancy figure in 1900 can be largely attributed to a higher rate of infant and child mortality (i.e. a lot of the 50 per cent who died had passed away before they even became adults). If a person survived childhood, then he or she could expect to live considerably longer than their mid-fifties. A young adult in 1900 still had a lower life expectancy than a young adult today, but the difference was ‘only’ about 7 years. Indeed, the older the age group, one considers the smaller this difference progressively becomes, until centenarians in 1900 had about as much future life ahead of them as centenarians today (Bromley, 1988; Kermis, 1983). In other words, the longer one lives, the less modern society can extend remaining life beyond what would have been experienced in earlier times.

Furthermore, it must not be supposed that the added life many modern people experience is necessarily blissful. Wilkins and Adams (1983), working from Canadian actuarial tables, calculated that for older adults, about 75 per cent of this

‘extra time’ is spent suffering from one or more physical disability and hence discomfort. Brattberg, Parker and Thorslund (1996) cite a similar figure of 73 per cent of Swedish adults in their late seventies, reporting mild or severe pain. These considerations give rise to the concept of active life expectancy (i.e. the average number of years remaining in which people can expect to lead a reasonably active life). Thus, the added life expectancy figures are something of a chimera – the so-called greying population is due more to childhood illnesses no longer being the killers they were, rather than to an ‘improvement’ in the way people age.

Furthermore, the shift in the balance of older people in the population is not without potential economic and social problems. If the proportion of older adults increases, then by definition the proportion of younger adults decreases. This means that a smaller fraction of the population is working and hence paying direct taxation (i.e. income tax, National Insurance, and similar). Such taxation forms the backbone of funding for welfare support schemes such as state pensions and (in most countries) national health care. Older people are of course pensioners and also are, along with children, the main beneficiaries of national health care. Thus, a ‘grey shift’ will create an increase in demand for services which are principally funded by a workforce diminishing in size. A simple method of expressing this is the old age dependency ratio, which is the number of people of pensionable age divided by the number of people of working age. This currently stands at about one fifth for most industrialised

WHAT IS AGEING? / 15
nations, but is expected to rise to one third or more by 2040. This is an instance of the demographic time bomb – the major and potentially catastrophic financial burden on the economies of the coming decades created by a greying population.

Governments are of course aware of this (though some would argue they have been slow to act), and moves to relieve the problem can be clearly seen in the UK through measures such as increasing the retirement age for women (in the decade from 2010, it will be incrementally raised to 65) and the increased incentives to prepare for later life through private pension schemes to ‘top up’ the small state pension.

Although the demographic time bomb is a potentially serious problem, it is important to put things into perspective. The discussions so far have dealt with industrialised nations. For developing countries, the figures for 1900 are more appropriate. It is a sobering thought that on a global scale, the commonest age of death is in the period between birth and five years (McHale, McHale and Streatfield 1979).

Differences in life expectancy

The prevalence of ageing has thus differed within the same society across historical time and differs today between industrialised and developing countries. It also differs between individuals and groups within the same society. A striking illustration of this is the Roseto effect (see Egolf et al. , 1992). This is named after an Italian-American community in Roseto, Pennsylvania, whose members’

susceptibility to heart disease increased as it became more ‘Americanised’. This neatly demonstrates that people can radically influence their life expectancy simply through which socio-economic group they belong to and the lifestyle they lead. In some instances, choice of lifestyle is voluntary, in others regrettably it is not. A much-cited instance of this is the effect of socio-economic class on life expectancy.

Essentially, the less affluent the social group is, the lower its life expectancy (e.g.

Macintyre, 1994; Roberge, Berthelor and Wolfson, 1995; Schwartz et al. , 1995).

Many reasons have been suggested for this phenomenon, not least of which are levels of stress, nutrition, and access to health care services.

Another major group difference is that ageing, particularly amongst octogenarians and older, is principally an experience of women. In peaceful societies (i.e. where heavy war casualties do not distort the figures), the balance of men and women is roughly equal until about 45 years. Thereafter, men die at a faster rate, so that by 70, there are approximately six women for every five men, and by 80, this ratio has moved to 4:1. Many reasons for the earlier deaths of men have been

16 / THE PSYCHOLOGY OF AGEING
suggested. A popular conception is that it is because men have traditionally led physically more strenuous lives. However, this seems at best a marginal explanation, since comparisons of men and women matched for levels of physical industriousness still show a strong sex difference in mortality rates. The phenomenon is seen across many animal species besides humans (Shock, 1977), implying that differences may lie at a chromosomal rather than an environmental level. However, a complex interaction of physical and environmental factors and differences in social behaviour (such as higher risk-taking amongst males) may also play a key role (see Lang, Arnold and Kupfer, 1994).

The fact that some lifestyles are more associated with longevity than others begs the obvious question – which is the best for a long and productive life? The search for the answer to this question has led some to make extravagant claims for remote rural populations in various parts of the world. The best known of these is a group of people in Georgia (in the former USSR) where a disproportionate number of centenarians were found. Various explanations were offered (many involving health foods and abstinence), but the prosaic truth is that there were no centenarians. The older adults, to avoid conscription into the Soviet Army, had used their parents’ birth certificates, thereby adding twenty or thirty years to their real ages. This draft dodging had backfired, because in later years, the Soviet authorities had seized upon the ‘well preserved’ older people and used them as a tourist attraction and propaganda vehicle. Detailed medical examinations debunked the story. Other cases of long-lived communities in Pakistan and Ecuador are explained by the simpler reason that high local levels of illiteracy coupled with poor population records had led to calculations of ages which were, to say the least, fraught with errors (see Schaie and Willis, 1991). Although some commentators still rather touchingly believe that these older people are indeed very old, the majority of evidence points to there being no ‘magical’ society in which people live significantly longer than elsewhere.

Indeed, for anyone looking for a lifestyle which offers the elixir of life, the answer seems to be the Ancient Greek adage ‘moderation in all things’. Studies of very old individuals usually show that they have fairly adaptive personalities and tend to be moderate in consumption and exercise (see Schaie and Willis, 1991). Not surprisingly, smoking (of any amount) and heavy drinking can reduce life expectancy by a decade of more. The evidence on eating is more equivocal. For example, it has been known since the 1930s that deliberately restricting calorific intake significantly increases the lifespan of many animal species (e.g. Masoro, 1988, 1992). However, this statement must be qualified. First, a restricted diet is only effective after a certain age – if begun too early, then ageing will be accelerated, not retarded (Aihie Sayer

WHAT IS AGEING? / 17
and Cooper, 1997; Gage and O’Connor, 1994); and second, the most reliable results are from studies of rodents: evidence on humans is more circumspect. Some variations of diet have also been suggested as ‘life prolonging’. Recently, an increased consumption of nuts has been proposed as a prophylactic against ischemic heart disease (Sabate, 1999). Again, vegetarians appear to live slightly but significantly longer than their omnivorous neighbours, probably because they are less prone to some common forms of illness, notably heart disease and some forms of cancer (see Dwyer, 1988). However, it is probably not a complete absence of meat which accounts for this. Similar results can be claimed for an omnivorous diet in which the proportion of meat is (by most Western standards) drastically lowered, though not completely removed (see Dwyer, 1898; Nestle, 1999).

However, it is worth noting that environmental and lifestyle factors alone are probably not a complete explanation. In spite of some of the claims which gain wide circulation in the media, many of the strategies for prolonging life are largely speculative and based on extrapolations from laboratory studies rather than real life observation (see Bernarducci and Owens, 1996). Again, findings on differing life expectancies illustrate trends across whole groups – they do not automatically dictate the fates of individuals within those groups. Not everyone who leads a healthy lifestyle will reach older age; not everyone who lives in a deprived environment will die young. In addition to environmental factors, life expectancy is to some extent determined by genetic inheritance. The most obvious manifestation of this is that longer-lived individuals tend to produce longer-lived offspring (Murphy, 1978).

Again, there is evidence from studies of identical twins (who are genetically identical) that there is a strong genetic influence on both mortality and susceptibility to many diseases (Iachine et al. , 1998; see also Korpelainen, 1999). It is clear how genetic inheritance might influence life expectancy through relatively ‘obvious’ factors such as a congenitally weak heart, but effects may also be less apparent, such as the finding that height may influence longevity (generally, shorter people have longer lives than tall people; Samaras and Elrick, 1999). However, just as with the evidence on environmental effects, some caution must be sounded. Not least is that teasing apart the effects of environment and genetics in determining what causes increases in longevity is notoriously difficult (see Yashin et al., 1999 for a recent review).

Thus, there is evidence that differences in ageing are attributable to both genetic and environmental causes.

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Definitions of Ageing

There is a surprising range of methods of describing the age of a person, some less obvious than others. For example, ageing can be described in terms of the processes which have affected a person as they have developed. These can be divided into relatively distant events (e.g. lacking mobility because of childhood polio) known as distal ageing effects, and those more recent (e.g. lacking mobility because of a broken leg) known as proximal ageing effects. Again, ageing can be defined in terms of the probability of acquiring a particular characteristic of later life. Universal ageing features are those which all older people share to some extent (e.g. wrinkled skin), whilst probabilistic ageing features are likely but not universal (e.g. arthritis).

These terms may be contrasted with the similar concepts of primary ageing (age changes to the body) and secondary ageing (changes which occur with greater frequency, but are not a necessary accompaniment). Some commentators add a third term – tertiary ageing – to refer to the rapid and marked physical deterioration immediately prior to death.

Another method of measuring ageing is to create a division between later and earlier adult life. However, the change from one to another is gradual and continuous, so any measure must be to some extent arbitrary. This is a manifestation of a familiar problem in science: How does one divide a continuum into subgroups? For example, if we consider the colour spectrum, it is obvious that there are bands of red and orange, but that these merge into each other. At what point in this red-orange boundary do we say that the colour has changed from orange to red? Similarly, at what point does someone move from being ‘middle aged’ to ‘elderly’? Despite the popular phrase, people do not become old overnight. Over several years one may observe a person’s physical and mental characteristics change, but it would be hard to pinpoint one precise moment in this process when a threshold was unambiguously crossed. This is one reason why the commonly used measure of chronological age is so unsatisfactory. Chronological age is simply the measure of how old a person is.

However, it is essentially an arbitrary measure. How often the Earth has circled the sun since a person was born tells us nothing about him or her unless this passage of time is correlated with other, more relevant changes. In fact, age alone can in some circumstances be a poor indicator. For example, it correlates poorly with physical changes. One can think of 70-year-olds who look like stereotypical older people (grey hair, wrinkled skin, etc), but one can also recall ‘well preserved’ individuals who lack these features (agerasia) and younger adults who look ‘prematurely old’. An important aside is that the latter should be distinguished from (extremely rare) disorders in which ageing is grossly accelerated. These include progeria (or

WHAT IS AGEING? / 19

Hutchinson-Gilford syndrome), in which the patient begins to age rapidly in early childhood and typically dies in their early teens and Werner’s syndrome, which develops in the teens, patients typically dying in their forties). In both diseases, patients develop physical characteristics and symptoms which resemble extreme ageing, but whether these are genuinely accelerated ageing or simply coincidentally resemble ageing is open to debate (see Bergeman, 1997; Hayflick, 1994). However, even excepting these unusual cases, chronological age by itself is far from being an infallible indicator.

Another commonly-used measure is social age. This refers to societal expectations of how people should behave at particular chronological ages. In some contemporary societies and in many more historical ones, a long life is/was considered to be the reward for pious behaviour (Gruman, 1966; Minois, 1989).

Two of the commonest beliefs arising from this have been classified as the antediluvian ageing myth and the hyperborean ageing myth – the beliefs that in ancient times or in a far distant land, respectively, there was/is a race of virtuous people with incredibly long lifespans. Modern industrialised societies take a different view. Later life is seen not as a time of reward but of enforced relaxation. Thus, western culture expects the over-sixties to behave in an essentially sedate fashion, and not surprisingly, the onset of later life is often indicated by retirement from full-time employment. The chronological age at which ‘old age’ begins is thus often judged to be between 60 and 65 (though some societies have ages ranging from 50 to 70; see Decker, 1980). Most gerontologists (people who study ageing) tend similarly to select a figure of 60 or 65 to denote the age of onset or threshold age (e.g. Bromley, 1988; Decker, 1980; Kermis, 1983; Rebok, 1987; Ward, 1984). This is not just to fit in with western stereotypes, but also because at around the threshold age various psychological and physical changes tend to manifest themselves, as shall be seen. In this book, the threshold age will be defined loosely as being between 60 and 65.

This rule of thumb is intentionally vague; to reiterate the caveats made earlier: (a)

there is not a single point at which a person becomes ‘old’; and (b)

chronological age is in any case an arbitrary and not very accurate measure, so the use of a single figure for the threshold would give it a speciously objective status.

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Some commentators further divide older adults into young elderly people and old elderly people (or ‘young old’ and ‘old old’). The precise ages involved in this categorisation can vary between writers, however. Some feel that ‘young elderly’

describes anyone between 60 and 75, and ‘old elderly’ anyone older than this, but others take different spans under the same terms (e.g. 60–80, or 65–80, or 65–75 for the young elderly group). Caution in reading reports using these terms is thus advised. A variant on this theme by Burnside, Ebersole and Monea (1979) proposed categories of ‘young old’ (60–69), ‘middle-aged old’ (70–79), ‘old-old’ (80–89), and ‘very old-old’ (90+). This seems simply to introduce new and unnecessary synonyms for ‘sixties’, ‘seventies’, ‘eighties’ and ‘nineties’. Another method divides the over-65s into the third age and the fourth age. The ‘third age’ refers to an active and independent lifestyle in later life, and the ‘fourth age’ to a (final) period of dependence on others. The terms have met with some favour, since they do not have the pejorative overtones which some people perceive in words such as ‘old’ or

‘elderly’. However, this is a moot point, since terms such as ‘third age’ in effect classify people in terms of how much help they need from others. It should also be noted that the terms used by gerontologists are not necessarily the ones employed (and by implication, liked) by older people. Midwinter’s (1991) survey found that the majority (72 per cent) of older people preferred the terms ‘senior citizen’ or ‘retired’, with only five per cent preferring ‘elderly’ and four per cent ‘older people’ (though these were used by 61 per cent of younger people). Stuart-Hamilton (1998) found a similar pattern (though with far less pronounced age group differences). There are sound reasons why researchers use terms such as ‘elderly’ or ‘old’; they have an objectivity which is lacking in terms such as ‘retired’ (which can in any case be misleading, since people often retire before their sixties). However, there are equally good reasons why people may prefer different terms, and sensitivity to this is advised.

Regardless of how they are labelled, signs of ageing exist, and can be both physical and mental. These are measured by biological age and psychological age respectively. Since the rest of this book is primarily about psychological ageing, no further mention will be made of it here. However, biological ageing cannot be passed over without some consideration, since many bodily changes (particularly those in the sensory and nervous systems) directly impinge on the workings of the ageing brain.

WHAT IS AGEING? / 21

Biological ageing

The term ‘biological age’ refers to the body’s state of physical development/
degeneration. Generally, the term is used fairly loosely to describe the general state of a person’s body. However, several more specific exemplars are sometimes used. These include anatomical age (the relatively gross state of bone structure, body build, etc); carpal age (the state of the wrist (carpal) bones); and physiological age (the state of physiological processes, such as metabolic rate). In the instances cited below, the general term is usually implied.

Ageing is the final state of development which every healthy and accident-free individual experiences. However, one must be careful not to overextend the word

‘development’ to imply that ageing necessarily involves an improvement. Indeed, one commentator emphasises this point by classifying later life as post-developmental:

‘all the latent capacities for development have been actualized, leaving only late-acting potentialities for harm.’ (Bromley, 1988, p. 30).

The body’s cells are not immortal – over a period of about seven years they all die and are replaced by new cells. The general consensus is that the central nervous system is an exception to this: its cells are not replaced when they die, though at the time of writing, evidence is growing that at least under laboratory conditions, some central nervous system neurons may be able to regenerate (see Brewer, 1999). The general cycle of cell death and regeneration has led some commentators to argue for a programmed theory of ageing (i.e. that cell death is in effect programmed). The best evidence for this is the evidence of a limit to the number of times a cell can be replaced. The Hayflick phenomenon (named after its discoverer: see Hayflick, 1985, 1994, 1997) states that living cells taken from the body and raised in vitro will only reduplicate themselves a limited number of times before dying (the Hayflick limit), and the older the body from which the cells are taken, the fewer the duplications before death occurs. Why this happens is open to debate. A plausible theory (though aspects of it are still disputed) is that each time a cell duplicates, a section of its DNA called the telomere shortens. When the telomere can shorten no more, the cell can no longer duplicate, and it dies. This seems to concur with the available evidence (see Olovnikov, 1996), and is further supported by the finding that reactivating telomeres extends cell life considerably beyond its natural Hayflick limit (see Johnson, Marciniak and Guarente, 1998).

However, it seems unlikely that the telomere alone is responsible for the ageing of cells, and other mechanisms likely to play a role include abnormal accumulation of

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DNA within the nucleolus (a structure within the nucleus of the cell: see Johnson, Marciniak and Guarente, 1998). Another theory – the somatic mutation theory of ageing – argues that the problem is compounded because replacement cells are not precise replicas but contain errors (a permutation of this – the error catastrophe theory – pins the blame on faulty protein replication). This faulty replication may be exacerbated by factors such as environmental pollutants and incorrect diet. In contrast, the autoimmune theory of ageing argues that ageing may be attributable to faults in the body’s immune system. First, by becoming less able to combat infection and second, by incorrectly identifying the body’s own cells as infectious agents, and attacking them. Yet another argument (the cellular garbage theory) is that ageing occurs because of toxins produced as by-products of normal cellular activity. These include a pigment called lipofuscin and a set of chemicals called free radicals. Evidence for each of the above theories is mixed: each may play some role, but each alone is unlikely to account for a notable proportion of the ageing process (see Bergeman, 1997; Hayflick, 1994; Sanadi, 1977). On the present evidence, it would seem that ageing at the cellular level is probably the accumulation of several processes whose effects may be greater as a sum than as parts.

Whatever the causes of bodily changes, there is no doubt that they do occur. One notable feature is cell loss. It is important to remember that this does not begin in later life, but in early adulthood, with most bodily systems showing a decline of 0.8–1 per cent per annum after the age of 30 (Hayflick, 1977). The course of this loss is very slow, and as most bodily systems have over-capacity built into them, it is only in about the sixth decade of life that the change is first apparent to the casual observer.

Botwinick (1977) notes that the decline is greater in complex than in simple functions. This is probably because the simpler functions have each only declined slightly, but, when used together in a more complex action, the total effect becomes multiplicative. As shall be seen, this disproportionate loss of complex over simple functions manifests itself repeatedly in both the ageing body and the ageing mind.

Another consideration is that many changes observed in older people may be due to disease rather than ageing per se. It is practically impossible to go through life without succumbing to at least some illnesses, and it is thus difficult to exclude the possibility that ageing changes are at least in part due to the cumulative effects of successive infections. The effect of even minor decrements in health is demonstrated by the ‘forty-seven healthy old men’ study (Birren et al., 1963). The researchers studied 27 completely healthy older men and 20 men who appeared healthy, but on extremely rigorous examination proved to have very slight evidence of potentially serious illnesses. This latter group showed a decline on a range of measures of mental

WHAT IS AGEING? / 23
functioning and physical measures such as brain wave rhythms. Birren et al. and subsequent commentators (e.g. Botwinick, 1977; Kermis, 1983) have argued that this shows that the decline was because of disease rather than ageing or the intrinsic health of the people studied, and other studies have recorded similar findings.

However, the argument can be pushed further and made circular – are some older people healthy because they have never contracted a disease, or have they never contracted a disease because they are healthy? If a weaker form of the argument is taken – namely, that the rate of ageing may be affected by infection – then the case for a role of illness is far more plausible.

The evidence presented so far implies that ageing is inevitable: a combined toll of genetics, faulty cell replication, ‘self-poisoning’ and illness may all make physical degradation unavoidable. However, is this planned? The programmed senescence theory argues that ageing is caused by evolutionary forces, and is in essence designed to happen. Readers who are Creationists are advised to skip this and the next paragraph. The evidence for this argument is at first sight plausible. Perhaps the best-known version of this theory is that bodies have an inbuilt programme to decay and die in order to make way for younger members of the species, and thus prevent the problem of overcrowding. Other versions include the concept that individuals grow weaker so that they become easier targets for predators, thereby removing younger species members (still capable of breeding) from being chosen as targets.

Such arguments are accepted uncritically by many gerontologists, but they are undermined by one simple fact: very few animals in their natural habitat reach old age. Accordingly, because older animals are so rare ‘in the wild’, it is unlikely that evolutionary pressure has created a method of ‘self culling’ a species – predators, disease and accident do a satisfactory job in themselves (see Hayflick, 1998; Kirkwood, 1988; Medawar, 1952). A more compelling explanation is provided by the disposable soma theory (Kirkwood, 1988). Modern evolutionary theory argues that an organism is driven to reproduce as much as possible, and this takes precedence over the organism’s personal survival. What matters is that the genes the organism carries survive (which body they are in is of secondary importance). Thus, by this theory, it would be better for a man to die at 20, having sired 30 children, than to die childless at 100 (see Dawkins, 1976). The disposable soma theory takes this theory and adapts it as follows. Body cells die and have to be replaced constantly. If they are not replaced, then the body parts concerned decline in mass and efficiency.

However, it is not possible to replace all cells equally effectively. The disposable soma theory argues that the best evolutionary strategy is to maintain the reproductive organs in top condition at the expense of the somatic (non-reproductive) body parts.

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Accordingly, the greater the energy invested in reproduction, the greater the bodily decay. Taken to extremes, this theory sounds like a Victorian homily, but at a subtler level the argument is persuasive, and Kirkwood (1988) provides strong supporting proof, to which the reader is referred.

If one accepts the disposable soma theory, then it follows that later life is not

‘planned’ by natural selection. In other words, when we consider an older person, it is difficult to argue that a particular change in behaviour or bodily function is

‘designed’ to happen. Ageing may be the accidental by-product of a need to maintain reproductive fitness; wrinkled skin, brittler bones, lowered memory span, lowered response speeds, may never have been deliberately planned – most individuals in natural surroundings are dead before these characteristics can ever manifest themselves (see Zwaan, 1999). Hayflick (1994) makes the useful analogy of the life course being, in evolutionary terms, like a satellite sent on a mission to survey a distant planet. Once a satellite has done its mission and sent back pictures of its target, it carries on into space, continuing to send back signals until eventually accident or simple decay terminate its activities. In a similar way, individuals, once they have accomplished their target of producing viable offspring, continue to live until accident or illness kills them. However, the life of the satellite after sending back the photos of the target or of the individual after breeding is coincidental. Enough

‘over-engineering’ has to be built into the system to ensure that the job can be accomplished with something to spare. We interpret this extra life afforded by the over-engineering as a ‘natural’ part of the lifespan, but in fact in evolutionary terms it is an accidental gift, not a right.

The ageing body

The general picture of changes to the ageing body is not an attractive one. For example, at the level of tissue, the skin and muscles become less elastic (the cross-linking theory of ageing); at the cellular level, there is a loss in the efficiency of the mitochondria (which generate energy within the cell); and at a molecular level, the somatic mutation theory of ageing has already been mentioned. Not surprisingly, these changes have a deleterious effect upon the functioning of bodily systems. For example, the urinary system becomes slower and less efficient at excreting toxins and other waste products. The gastrointestinal system is less efficient at extracting nutrients. There is a decline in muscle mass and the strength of the muscle which remains. The respiratory system can take in less oxygen. The cardiovascular system receives a double blow – the heart decreases in strength while simultaneously a hardening and shrinking of the arteries makes pumping blood around the body more

WHAT IS AGEING? / 25
energy-consuming. The result is that the average 75-year-old person’s cardiac output is approximately 70 per cent of the average 30-year-old’s (Aiken, 1989; Kart, 1981; Kermis, 1983). Many of these changes may be lessened by appropriate diet and exercise (DeVries, 1975; Fries and Crapo, 1981), though it should be noted that the experimental methods used to support this argument have been criticised (Thornton, 1984).

These changes have a disadvantageous effect on the functioning of the brain and hence on psychological performance. For example, a decline in the efficiency of the respiratory and cardiovascular systems will restrict oxygen supply and thus the energy available for the brain to function. Birren, Woods and Williams (1980) suggest that the slowing of reaction times, even in apparently healthy older people, may be due to a restriction in blood supply. Cardiovascular illness in addition to normal senescent decline will also have a detrimental effect on brain functions (Kermis, 1983). The most notable example of this is the stroke, where blood supply to a section of the brain is interrupted, causing death of the affected brain tissue. At a less severe level, some older people may have an oxygen supply so constricted that they fall asleep after meals, because the energy required by the digestive processes deprives the brain of sufficient oxygen to remain conscious. Changes in other systems may have subtler effects. For example, a decline in the urinary system may mean a high level of toxins accumulating in the body, in turn affecting the efficiency of neural functioning. If an older person is receiving drug therapy, then failure to excrete the drug from the system with sufficient speed may lead to overdosing problems, including acute confusional state, or delirium (see Chapter 6). A decline in the gastrointestinal system can have similar far-reaching consequences. If the decline has the effect of lowering an older person’s interest in food, then malnutrition can result. This is especially serious from a psychological viewpoint if the person develops a deficiency of vitamin B12, since this can trigger dementia-like symptoms.

Another effect of ageing bodily processes is that it can cause a person to revaluate their state of being. This is not necessarily serious. Being aware that bones are becoming more brittle and muscles less strong may create a reluctant but pragmatic sense of caution. However, in others, these physical signs can lead to depression (Raskin, 1979). Weg (1983) argues that the majority of older people still have ample capacity to deal with the demands of everyday life. However, whether they do is another matter.

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The ageing sensory systems

The senses are the brain’s means of contact with the surrounding environment and, accordingly, any decline in them directly impinges on the workings of the mind.

Age-related declines in perception deprive the brain of a full experience of the world, but it would be unrealistic to assume that such a loss begins in later life. Like many aspects of age-related decline, the changes often start in early adulthood, and it is important to bear this in mind when reading the sections below.

vision

It is a frequent complaint of older people that their sight ‘isn’t what it used to be’.

This is usually true: aside from relatively simple problems of long- and short-sightedness, about a third of people aged over 65 have a disease affecting vision (Quillan, 1999). A common problem is the decline in accommodation (the ability to focus at different distances), leading to presbyopia (‘old sight’ – ‘presby-’

indicates ‘old’), characterised by long-sightedness. This is probably due to the ageing lens losing some of its elasticity and hence focusing power. The most serious visual handicap most people suffer is a loss of acuity (variously defined as ‘ability to see objects clearly at a distance’ or ‘ability to focus on detail’). Bromley (1988) estimates that about 75 per cent of older adults need spectacles, and many will not have full vision even with this aid. Corso (1981), in his excellent review of the literature, observes a marked decline in acuity with age, though he notes that the problem can be at least partially alleviated if visual displays have a high contrast in luminance (e.g.

black on white rather than black on grey). Indeed, at such levels, older people’s acuity (when wearing glasses) may be at or near more youthful norms (Haegerstrom-Portnoy, Schneck and Brabyn, 1999). But for lower levels of contrast, older people’s sight may be much worse. This is borne out by studies of contrast sensitivity function (CSF). Experimental participants are shown patterns of alternating light and dark parallel lines. The thickness of the lines can be varied, as can their luminance. Obviously, broader lines which vary strongly in luminance are the easiest to see. By reducing the thickness and/or contrast in luminance, it is possible to make the pattern ‘disappear’: the observer sees a homogeneous grey, because he or she can no longer distinguish between the lines and they blur into one. The CSF is a formula which expresses the smallest difference in luminance for a given thickness of line which a person can still see as a pattern rather than as a grey splodge. The less the difference in luminance, the more sensitive the person’s vision is. Sekuler, Owsley and Hutman (1982) found that the CSF declines in later life (furthermore, worsening CSF may be indicative of ophthalmic disease – see Woods, Treagear and Mitchell,

WHAT IS AGEING? / 27

1998). For relatively broad patterns (measured in cycles/degree, 0.5 and 1 c/deg), the contrast in brightness had to be significantly greater before older people could see the pattern. A further complicating factor is that for some line thicknesses, younger participants’ performance can be improved if the pattern is moving.

However, no such advantage is conferred on older people by this procedure (Sekuler, Hutman and Owsley 1980). More recent research suggests that these problems may be due at least in part to the neural system rather than receptors in the eye itself (see Pardhan et al. , 1996).

Another example of poor CSF in older adults is in recognising and matching pictures of faces when the contrast in luminance has been reduced. Such findings bode ill for the everyday vision of older people. Sekuler and Owsley (1982) comment that most studies of acuity are conducted in optimal lighting conditions.

However, in real life, many items are dimly lit, visual displays rarely provide a strong contrast in luminance and, as has been seen, older people are especially disadvantaged in these conditions. Thus, standard measures of acuity may underestimate the degree of handicap. This argument is further strengthened by the finding that acuity loss is appreciably worse when viewing a moving rather than stationary display (Fozard et al., 1979).

Beyond considerations of acuity, practically all other aspects of vision worsen in later life (Haegerstrom-Portnoy, Schneck and Brabyn, 1999). For example, the visual threshold (the dimmest light that can be seen) increases with age – in other words, older people cannot see lights as dim as younger people can see (Elias, Elias and Elias, 1977; McFarland and Fisher, 1955). This is probably due to a variety of factors, including a diminution in the maximum expanse of the pupil, and poorer metabolism of receptor cells (Pitts, 1982). Similarly, the rate at which people can adjust to low level lighting conditions (dark adaptation) decreases with age (Domey, McFarland and Chadwick, 1960). The converse – ability to recover from glare – is also reduced, sometimes by several hundred per cent (Carter, 1982). This clearly has practical implications (e.g. for older people’s ability to drive at night; see Scharwey, Krzizok and Herfurth, 1998, who estimate 40 per cent of older adults have impaired night driving vision). Another important consideration is the change in colour perception: older adults perceive the world as being yellower. Colours at the yellow end of the spectrum (red, orange and yellow) are identified reasonably well, but greens, blues and purples become harder to discriminate between (note that this problem does not typically manifest itself before people are in their eighties). Many commentators have argued that this is due to the lens yellowing with age, but this cannot be the full explanation. Some unfortunate individuals who have had a lens surgically removed

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still perceive the world as having a yellow tinge. The reason is thus probably due to changes in the nervous system (Marsh, 1980).

Older adults are also slower at processing visual stimuli, and need to see them for longer before they can be accurately identified. Also, their disadvantage grows disproportionately worse the dimmer the stimulus at which they are looking. This slowing occurs in both the perceptual stages (i.e. the retina and nerves leading to the brain) and in the sections of the brain responsible for processing visual information (Moscovitch, 1982; Walsh, 1982).

The size of the visual field also diminishes. A relatively minor problem is that older people cannot move the eyeball as far up as younger adults, with the result that older people have to move their heads to see some object above them which younger adults can see with eye movements alone. A more serious problem is a loss of peripheral vision (i.e. how ‘wide’ the field of view is). Onset of this decline occurs in middle age, but becomes far more pronounced in the over-75s (Jaffe, Alvarado and Juster, 1986).

The above problems can be serious and annoying for older people, but they are not necessarily crippling. In addition, many of the problems in vision arise prior to later life, in some instances as early as the mid-thirties (Corso, 1987). However, it is pertinent to remember that about 7 per cent of 65–74-year-olds and 16 per cent of people over 75 are either blind or severely visually handicapped (Crandall, 1980).

The principal causes of this are cataracts (the lens becomes opaque); glaucoma (excess fluid accrues in the eyeball, and the resultant pressure permanently destroys nerve and receptor cells); macular degeneration (the macular or ‘yellow spot’ on the retina, which has the greatest acuity of vision, degenerates; see Sunness et al., 1999); and diabetic retinopathy (damage to the blood vessels of the retina as a result of diabetes). These illnesses are not confined to later life, but they are certainly much commoner (Corso, 1981; Quillen, 1999). It should be noted that they can also be either prevented or at least the worst effects can be tempered if they are identified early enough. For example, the longer the time since last visiting an eye specialist, the worse a discovered case of glaucoma is likely to be (Fraser, Bunce and Wormald, 1999).

hearing

Hearing declines gradually throughout adult life, so that as young as 50, many people are impaired in at least some circumstances, such as listening to faint sounds (Bromley, 1988). For some individuals, the degree of hearing loss can be a severe handicap. Stevens (1982) estimates that 1.6 per cent of 20–30-year-olds have serious

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hearing difficulties, compared with about 32 per cent of 70–80-year-olds. This figure rises to over 50 per cent for those aged over eighty (Herbst, 1982). Other commentators, using slightly looser criteria, posit even higher estimates for hearing difficulties, with figures of 75 per cent for people aged over 75 being not uncommon. The rate of hearing loss can be exacerbated by environmental conditions. For example, a poor diet lacking in vitamin B12 may have a significant effect (Houston et al., 1999). Again, deafness amongst long-term workers in heavy industry is well documented (e.g. Sekuler and Blake, 1985). Men tend to have greater hearing loss than women. Typically, their decline is at twice the rate and begins earlier (by 30) though sensitivity to low frequencies (<1000 Hz) remains better (though there is considerable individual variation in patterns of loss; Pearson et al. , 1995). It has been supposed that this is because men have tended to work in noisier places than women. However, evidence indicates that even amongst people in ‘quiet’ occupations, there is still a gender difference (Pearson et al., 1995). This suggests more innate reasons for some hearing loss, and indeed there appears to be a genetic component to at least some types of hearing loss in later life (Gates, Couropmitree and Myers, 1999). However, in general it is impossible to adduce how much of hearing loss is due to ageing per se, and how much to the environment, though almost certainly both play a role and there is no doubt that it is a considerable problem (see Gates and Rees, 1997).

Working from the outside of the ear inwards, an assortment of age-related changes may be noted. One of gerontology’s more esoteric findings is that ageing ear lobes increase in size by several millimetres (Tsai, Chou and Cheng, 1958). The functional significance of this remains unclear. The elderly ear canal can get blocked with wax more easily, causing hearing loss, though this is easily treated. Changes in the middle ear are more severe and usually less easily solved. The bones of the middle ear – the hammer, anvil and stirrup (or malleus, incus and stapes) – tend to stiffen with age, through calcification or arthritis. This affects the transmission of sound, most particularly for high frequencies. The problem may be compounded by changes in the inner ear, where cell loss is usually concentrated in the receptors for high frequency sounds (Corso, 1981; Gates and Rees, 1997; Pearson et al., 1995). Leading from the inner ear to the brain is the auditory nerve. This bundle of nerve fibres diminishes in size with age. The atrophy is probably due to a combination of loss of blood supply, and bone growth restricting the channel for the fibres (Crandall, 1980; Krmpotic-Nemanic, 1969).

A frequent misconception about hearing loss is that all sounds are perceived as quieter and harder to hear. Some forms of hearing disability do take this form, but not

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all. The commonest form of hearing loss in older people is a condition known as presbycusis (or presbyacusis). This condition can occur in several forms (see Cohn, 1999), but all have in common a proportionately greater loss in perception of high than low frequency sounds. Sometimes the problem is exacerbated by a phenomenon called loudness recruitment: higher pitched sounds are perceived as louder than normal intensity, often to the point of being painful and/or distorted.

Presbycusis clearly handicaps a sufferer. At best the auditory world becomes muffled; at worst, it is agonisingly painful.

Causes of presbycusis are several-fold. This is a heavily-researched area, and explanations are legion. The loss of high frequency detection because of a stiffening of the middle ear bones has already been mentioned. Again, a lifetime in a noisy environment tends to exert greatest damage to high frequency detectors in the inner ear (which are more damage-prone than lower frequency detectors). An ingenious theory that snoring may be a contributory factor seems to be unfounded (Hoffstein et al., 1999). Research on neurological functioning within the brain indicates that presbycusis may in part be a product of age-related changes in the way some nerves function (e.g. Caspary, Milbrandt and Helfert, 1995; Oku and Hasegewa, 1997). It may also be influenced by genetic factors (Bai et al., 1997).

Whatever the causes, presbycusis is a serious problem. For example, sound localisation (the ability to detect where a sound is coming from) is impaired (see Rakers, Van der Velde, and Hartmann, 1998). Again, loss of ability to hear high-pitched sounds will of course make the world sound ‘muffled’, and this has serious consequences. Speech sounds are a composite of high and low frequencies, but it is usually the high frequency components which are crucial in distinguishing them from each other (this particularly applies to consonants). Thus, presbycusis makes following speech (particularly conversations) very difficult.

Presbycusis is not the only common hearing problem in later life. For example, there is a worsening of pitch discrimination, sound localisation, and also in perceiving timing information (see Marsh, 1980; Schneider, Speranza and Pichora-Fuller, 1998; Strouse et al., 1998). In addition, up to 10 per cent of older adults suffer from tinnitus, or what is commonly (if slightly inaccurately) known as

‘ringing in the ears’ (Kart, Metress and Metress, 1978). This can block out other auditory signals as well as causing suffering in its own right.

A further problem with hearing in later life is that the decline appears to be another manifestation of the age x complexity effect. Generally, the more complex the speech signal, the more older people are disadvantaged relative to younger adults (Corso, 1981). For example, when detecting signals played against a background of

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noise or competing signals compared with a silent background (e.g. Bergman et al., 1976; Dubno, Dirk and Morgan, 1984; Pichora-Fuller, Schneider and Daneman, 1995). However, when signals are familiar phrases or ones expressing familiar concepts, there is no or little age difference (Hutchinson, 1989).

A complicating factor in studies of hearing loss is that the degree of handicap can only be partly explained by objective measures. Thus, older adults’ subjective ratings of their handicap are often at some variance with an objective measure of hearing loss, and Corso (1987, p. 45) estimates that ‘audiometric data explain less than 50 per cent of the variance in hearing handicap in the elderly’ (for a more recent survey of self-reported hearing problems in older adults, see Slawinski, Hartel and Kline, 1993). However, whatever the ‘true’ size of the problem, given that hearing is such an integral part of everyday life for most people, it is not surprising to find that a loss (even marginal) is associated with lowered feelings of well-being (Scherer and Frisina, 1998), empowerment (Ryan, 1996) and even cognitive functioning (Naramura et al., 1999). It should be stressed that hearing loss only has to be relatively slight for signs of impairment to manifest themselves (e.g. Kart, 1981).

Herbst (1982) observes that most societies have held a grudge against deaf people since the start of recorded time. To the Ancient Greeks, the word ‘deaf ’ was synonymous with ‘stupid’, and to the early Christians, deafness was a curse, because in preliterate societies, it blocked the person from holy teachings. In modern times, this bias has continued. For example, deaf charities tend to receive fewer donations than those for the blind, because, Herbst argues, whilst blindness cuts one off from things, deafness cuts one off from people. This is perhaps rather too tenuous an argument, but it is not without some validity.

This alienation of deaf people is of course illogical, but an encounter with a hearing impaired person often leads able hearers into behaving like the stereotype of the Englishman abroad, complaining that the failure in communication is solely due to the natives having the temerity not to learn English. In other words, the speaker can never be at fault. The older person with hearing problems is usually well aware of this, and is often cowed into submission and silence rather than risk anger or ridicule.

This removal from social intercourse can cause a person to become depressed and still more withdrawn. This may be interpreted by outsiders as evidence of antisocial behaviour or even the onset of dementia, and the person is accordingly shunned even more. This can cause further withdrawal, and thus a vicious cycle is created. It is small wonder that hearing loss is associated with loss of self-esteem, as noted above.

However, there is a danger that the social effects of hearing loss can be over-dramatised. Whilst it is right and proper that deafness-induced isolation should

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be carefully monitored, there is evidence that the level of social isolation is poorly correlated with the specific level of hearing loss (see Norris and Cunningham, 1981; Weinstein and Ventry, 1982). There are similar findings on hearing aid use (see Brooks and Hallam, 1998). In other words, hearing loss may trigger negative feelings, but the level of hearing loss may be relatively unimportant. Such evidence does not obviate the need for help, of course, and a variety of remedial measures are available (see Burnside, 1976). However, as Herbst (1982) argues, one of the biggest problems is getting older people to come for help in the first instance, because of the perceived stigma (plus the fact that hearing loss tends to be gradual, making the change harder to detect in oneself), many people do not seek medical attention at all until they are very hard of hearing.

other senses

Declines in the other senses are generally of less interest to the psychologist because they do not impinge as directly on psychological functioning. Nonetheless, they must be noted.

Taste The tastes humans perceive can be divided into four primary types: bitter, sour, salty and sweet. Commentators are divided on the extent to which ageing causes a decline in sensitivity to these. For example, Engen (1977) argues that whilst there is a general decline, sensitivity to bitter tastes increases with age. However, Schiffman et al. (1995) found a loss in sensitivity to bitter tastes, whilst Cowart, Yokomukai and Beuchamp (1994) found decreased sensitivity to some bitter-tasting substances but not to others. Weiffenbach, Baum and Berghauser, (1982) found a decline in sensitivity to bitter and salty tastes, but no change in sweet and sour sensitivities (though detection of sweet and sour may decline in centenarians; see Receputo, Mazzolini, Rapisarda et al., 1996). The data on detection of complex tastes is more clear cut, with older people showing a marked decline in detection of many everyday food items (see Bischmann and Witte, 1996; Murphy, 1985; Schiffman, 1977), and in detecting a primary taste when presented in a mixture of other tastes (Stevens, 1996). However, although there may be a slight decline, sweetness detection appears to be relatively well preserved (Walter and Soliah, 1995). Furthermore, Stevens et al. (1995) note that although there is an overall age-related decline, there is considerable variability between individuals (in other words, some will show more decline than others). In addition, the connection between level of taste sensitivity and food intake and preferences is far from clear-cut (see de Jong et al. , 1999; Rolls, 1999).

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Smell The associated sense of smell appears to show relatively little change in very healthy older adults (e.g. Corso, 1981). However, since most older adults experience illness in one form or another, it would be more demographically representative to argue that most older adults will show at least some decline (see Doty, 1990; Finkelstein and Schiffman, 1999). However, the magnitude of this decline is debatable, and declines, though statistically significant, have often been reported as slight, even in centenarians (Receputo, Mazzoleni, Rapisarda et al., 1996). It is worth noting that many older adults have no awareness of a decline (Nordin, Monsch and Murphy, 1995). Relatively recent research has demonstrated that there is an appreciable decline in smell in the early stages of Alzheimer’s Disease (e.g.

Moberg et al., 1997), and this may prove to be a useful diagnostic aid.

Touch Older adults have higher touch thresholds (i.e. firmer stimulation of the skin is required before it is detected: see Stevens and Patterson, 1996; Thornbury and Mistretta, 1981), and similarly, sensitivity to the temperature of objects decreases.

However, the changes are not necessarily clear-cut. For example, the effects vary greatly in their magnitude across individuals. Again, sensitivity to vibration is difference across the frequency range. At relatively high vibration speeds (250 Hz), older adults are worse at estimating the strength of the vibration. However, at a lower frequency (25 Hz) there is no significant age difference (Verrillo, 1982). The touch sensors are housed in the skin, and accordingly, it is tempting to link the decline in sensitivity to the obvious thinning and wrinkling in an older person’s skin.

This may be a partial explanation, and there is evidence that at least part of the decline is due to a decrease in the number of touch sensors in the skin (Gescheider et al., 1994). Woodward (1993) argues that when changing properties of the skin are controlled for, an age difference still remains, implying that the decline may also be due to changes in the nerves conducting information to the brain.

Pain Some researchers have reported an increase in the pain threshold of older people: in other words, they can endure more extreme stimuli without perceiving them as painful (e.g. Benedetti et al., 1999; Harkins, Price and Martelli, 1986; Lasch, Castell and Castell, 1997). This may be due to a decline in the number of sensory receptors in later life. However, some studies have failed to find any changes in pain perception, and this discrepancy may be due to where on the body the experimenters inflict the pain (Bromley, 1988). In addition, the emotional meaning of pain may differ between ages. For example, older adults tend to be less distressed about the lessening of mobility through the pain of an illness, because they may generally have lower expectations of what they can or ‘should’ do at their particular age (see Williamson and Schulz, 1995). There are also serious methodological problems

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with pain studies. Apart from the obvious ethical considerations which curtail the range and strength of pain inflicted, there is also the problem of creating a suitably objective measure for such a subjective sensation as pain (see Gibson and Helme, 1995). In addition, there is evidence that the range of factors which affect older adults’ perception of pain may be more varied and less easily grouped together than in younger adults (see Corran et al., 1997; Manetto and McPherson, 1996).

overview

The clear message from this brief survey of the ageing senses should be readily apparent – the information reaching the brain from the surrounding environment is constrained in its range, is less detailed, and, given the general slowing of the nervous system, takes longer to arrive. This hardly bodes well for the ageing intellect (see Lindenberger and Baltes, 1994); nor indeed for the personality if an elderly person’s self-image is affected (it is known that illness is linked to level of depression in older people; see Williamson and Schulz, 1992). However, it should be noted that the ageing brain is in turn not making the best use of the incoming sensory information.

A notable pattern of decline in the ageing perceptual processes is that the older mind is less adept at integrating several strands of sensory information into a cohesive whole (e.g. complex versus simple tastes, complex versus simple auditory signals). As mentioned earlier in this chapter, the principal age deficits appear to occur when several simple processes must be operated in tandem.

Basic anatomy of the nervous system

It is important that the reader has some knowledge of the nervous system in order to understand the psychological and neurological changes which occur in later life (particularly in the dementias). Accordingly, this section is devoted to a basic description of neuroanatomy. As far as possible, this is presented in non-technical language. Those readers already familiar with neuroanatomy can safely skip this section.

The neuron

The basic building block of the nervous system is the neuron (or, less accurately, the

‘nerve cell’). Neurons vary enormously in shape and size, but all have the basic function of receiving signals from other neurons or specialised sensory receptors (for touch, pain, heat, etc), and passing signals on to other neurons or sense organs.

Neurons connect with each other at junctions called synapses, where signals are

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transferred from one neuron to another. When a neuron is activated, an electrical pulse passes down its length until it reaches a synapse, where two neurons meet with only a microscopic gap separating them. The activated neuron ‘spits’ a chemical across the gap onto the receiving neuron, causing it to do one of four things: (1)

It was dormant, and it is activated into sending a signal.

(2)

It was already sending a signal, but the new input causes it to fire with greater vigour.

(3)

It was already active, but the new input makes it either stop firing, or fire with less vigour.

(4)

It was dormant, and the new input prevents other neurons exciting it into firing.

In cases 1 and 2, the effect is said to be excitatory and in cases 3 and 4 the effect is said to be inhibitory. Therefore, neurons can either spur each other on, or they can suppress activity. The chemical transmitters employed to do this (i.e. the chemicals

‘spat’ at synapses) are called neurotransmitters. On some occasions, it is convenient to classify neurons according to the type of transmitter they use. For example, there is the cholinergic system, which uses the transmitter acetylcholine. About 90 per cent of the neurons in the brain are cholinergic. The other principal use of the cholinergic system is in the control of skeletal muscle. Conversely, the noradrinergic system (using noradrenaline) is primarily employed in the control of smooth muscle. Many neurons are covered with a layer of fatty substance called myelin, which acts rather like the insulation around electrical wires – it stops the signal from escaping, and also helps to increase the speed at which the signal is sent.

Anatomy of the nervous system

The simplest division of the nervous system is into the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and the spinal cord, the PNS of the neurons connecting the CNS to the rest of the body. The nervous system consists of at least 1010 neurons, most of which are in the brain. The ‘textbook definition’ is that the fundamental difference between the neurons of the CNS and the PNS is that the former cannot be replaced if they die, whilst the latter can (though as noted above, see Brewer, 1999).

36 / THE PSYCHOLOGY OF AGEING

PNS anatomy

The PNS can be divided into subsections, according to function. Afferent neurons carry information into the CNS, and are said to be somatic if they carry information from the joints, skin of skeletal muscle, and visceral if they carry information from the viscera (intestines). Efferent neurons carry commands from the CNS to the body, and are said to be motor if they send signals to the skeletal muscle and autonomic if they send signals to glands, smooth muscle, cardiac muscle, etc (i.e. bodily functions over which there is little conscious control).

CNS anatomy

The spinal cord’s principal function is to channel information between the PNS and the brain. However, it is capable of some simple processing. By means of a mechanism called the reflex arc (a simple connection between afferent and efferent neurons), it can make the body respond to some forms of stimulation. Many reflexes (such as the well-known knee jerk reflex) are produced in this manner.

The spinal cord projects into the brain, or, more accurately, the section of the brain called the brain stem. Many lay persons think of the brain as being a homogeneous mass of ‘grey matter’, but in fact the brain is a collection of distinct though interconnecting structures. For anatomical and functional reasons, the brain is often divided into four principal divisions. The first is the brain stem. Located behind this at the base of the skull is the cerebellum. Located above the brain stem is the diencephalon, or interbrain. Seated above and overlapping the other three segments is the cerebral cortex (often simply called the ‘cortex’), the wrinkled ‘top’

of the brain. Generally, the further a structure is away from the spinal cord, the more sophisticated its functions.

The brain stem is chiefly concerned with the maintenance of ‘life support’ mechanisms, such as control of blood pressure, digestion, respiration, and so forth. It also receives inputs from the senses and channels them through to other systems in the brain.

The cerebellum receives somatic input, and information from the semicircular canals (the balance sensors located in the inner ear). Given this information, it is not surprising to learn that the cerebellum is responsible for co-ordinating movement.

The diencephalon is a collection of several components. Among the more important of these are the following. The thalamus co-ordinates and channels sensory information and the execution of motor movements. Damage to this region gives rise to Parkinsonism (see Chapter 6). The hypothalamus might be loosely said to control

WHAT IS AGEING? / 37
bodily needs: hunger and satiety, sexual drive, anger, and so forth. The hippocampus is, in evolutionary terms, amongst the oldest sections of the brain. It is involved in emotional control, but of principal interest to psychologists is its role in memory.

Some unfortunate individuals who have had this areas of the brain destroyed (by disease or accident) cannot retain any new information in their memories for more than about two minutes. Therefore, the hippocampus is in some manner involved in retaining information in a long term memory store.

The cortex is responsible for the execution of most higher intellectual functions. It is divided into two hemispheres. The divide runs vertically from front to back, along the centre of the head. The hemispheres are linked by several pathways, of which the most important is the corpus callosum. For most individuals, the right hemisphere is principally responsible for visuo-spatial skills, the left for verbal skills.

The cortex can also be divided into lobes, based upon the psychological functions which each of them controls. The frontal lobes extend from the front of the skull back to the temples. They are mainly involved in the control and planning of actions, such as producing sequences of movements, getting words and letters in the right order in speech and spelling, and producing socially appropriate behaviour.

The frontal lobes are also involved in memory – principally in identifying which events in memory occurred in the recent, and which in the distant, past. The temporal lobes are situated in the positions of the right and left temples. One of their principal tasks is in interpreting information, and in particular the left temporal lobe is vital in comprehending speech and print. The temporal lobes are also strongly involved in memory, particularly the long term retention of information. Because of the specialisation of the left and right hemispheres, the left temporal lobe tends to store verbal memories and the right temporal lobe tends to store spatial information.

The occipital lobes are at the rear of the brain. They are involved in reading, but their principal function is vision. Virtually all processing of visual information takes place in the occipital lobes. The parietal lobes are located at the ‘top’ of the brain, surrounded by the other three lobes (they lie roughly in the position of an Alice band or the headband of a pair of headphones). In part they are responsible for maintaining awareness of the body’s state and location. Their principal intellectual role might be said to be symbol interpretation, and they are involved in object recognition and reading.

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Neuronal changes in later life

Researchers agree that the brain decreases in weight by 10–15 per cent in the course of normal ageing (Bromley, 1988). This has potentially serious repercussions for psychological functioning, especially since cells in the central nervous system probably do not replace themselves (even if CNS neurons can in theory replace themselves as noted above, it is unlikely that this is widespread). The reasons why this loss occurs are far from clear. Most probably, several factors are responsible, and the relative contribution of each may vary from person to person. One possible cause is decreased cerebral blood flow, leading to neurons starving of oxygen and thus dying.

However, Hunziker et al. (1978) demonstrated that changes in cerebral blood supply seem to be an adjustment to a decline in the number of neurons rather than vice versa.

Another explanation is that many older people suffer from miniature strokes or infarcts, where a minute portion of the brain atrophies because of the demise of the local blood supply. The older person is unaware of this happening, and it is worth stressing that usually the number of infarcts is small, and can be regarded as symptomatic of normal ageing. However, in some individuals, they dramatically increase in number, giving rise to multi infarct dementia (see Chapter 6). A third explanation is that the cerebral blood supply, when operating efficiently, filters out possible toxins in the blood before they reach the brain, by a mechanism called the blood-brain barrier. If ageing causes this to decline, then the brain might be exposed to potentially damaging toxins. Generally, such declines in metabolism and cardiovascular problems mean that even if their death is not caused, the neurons are less well supplied with oxygen and blood glucose and cannot operate as efficiently (see Meier-Ruge, Gygax and Wiernsperger, 1980; Woodruff-Pak, 1997).

More important causes of cellular decline are the changes which occur in the neurons’ own physiology. There is some debate over whether cells die, or in fact they survive, but are simply reduced in size. It is documented that for many sections of the brain, neurons shrink in size in later life (partly because of a thinning of the myelin sheath) and decrease the number of connections made with other cells. However, estimates of actual losses differ considerably between researchers because of the technical difficulties in taking measurements. Schaie and Willis (1991), from an overview of the literature, place an estimate of 5–10 per cent. Perlmutter and Hall (1992) from their overview, observe that some of the claims of cell loss have come from studies of patients with diseased brains, and that studies of healthy elderly brains (healthy up to the point where the patient died, that is) have tended to show little or no cell loss (though there is a reduction in cell size). More recently, researchers have found that cell loss may be particularly concentrated in some areas

WHAT IS AGEING? / 39
of the brain, notably the hippocampus, the cortex as a whole and the temporal lobes in particular (see Adams, 1980; Woodruff-Pak, 1997); in other words, the areas of the brain most strongly linked with intellectual functions and memory. Some other brain areas, such as the hypothalamus, are relatively unscathed, whilst others, such as the brain stem, are partly affected (Selkoe, 1992).

It is important that the discussion of cell loss is put in its proper context.

Although catastrophic cell loss as witnessed in dementia is sometimes linked to a decline in psychological skills, the same correlation cannot be confidently made in non-dementing ageing. First, cell loss per se may not be as drastic an issue as it at first appears. There are much larger cell losses in early infancy, when the growing brain jettisons millions of neurons which are not integrated into the developing networks of active neurons. However, nobody looks at this cell loss and decides that it must seriously lower intellectual functioning. Second, it seems likely that the mind can cope with considerable cell loss. The issue of how the brain stores information is hotly debated. However, it seems likely that it is spread across networks of thousands of neurons (see Stuart-Hamilton, 1999a). The departure of even a reasonably large proportion of neurons should not matter, because the neurons which remain in the network hold sufficient of the ‘memory pattern’ for the information to continue to be stored efficiently. Therefore, one cannot assume that cell loss will automatically lead to a decline in intellectual ability. In addition, recent evidence suggests that if neurons are lost, then the surviving neurons may produce new ‘branches’ to form new connections with other surviving neurons, to compensate for this loss (see Brewer, 1999; Selkoe, 1992; Woodruff-Pak, 1997).

In part the unresolved nature of this issue is due to limitations in measurement techniques. Not least of these is that current technology cannot count nerve cells in living brains – instead, it can only be done on samples from corpses. There are considerable methodological problems with this. For example, one cannot take samples from the same person across their lifespan, so judgements about age differences in cell counts have to be made by comparing young adults who died young, with older adults who died later in their lifespans. Finding that the brains of dead younger adults have more cells may indicate that had they lived longer they too would have shown a cell loss, but it is also not inconceivable that the older adults when they were younger had fewer brain cells (see Woodruff-Pak, 1997). Until further refinements of measurement are made, this will remain a moot issue.

Other methods of assessing ageing changes in the brain concentrate upon measurements of brain activity and relatively large-scale structures. The earliest method is the electroencephalograph (EEG). This measures the electrical activity

40 / THE PSYCHOLOGY OF AGEING
on the scalp, and from this the activity of the brain within can be roughly surmised.

The electrical pulses recorded by the EEG are transmitted across a range of frequencies: delta (0–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), and beta (>12 Hz).

It used to be supposed that EEG frequencies simply slowed down in later life, but recent evidence shows that the situation is more complicated than this. Alpha activity is largely unaffected by ageing, whilst for other frequency bands there is ‘a general desynchronization with age, characterised by decreased slowing and increased fast activity’ (Duffy and McAnulty, 1988, p. 274). Several researchers have observed age differences in EEG recordings made whilst experimental participants perform simple intellectual tasks, such as scanning a list of letters to see which has been presented in a previous exposure, or choosing the correct response in a reaction time task. Usually the age difference manifests itself as a less strong electrical pulse, and sometimes the pulse takes longer to be initiated (Marsh and Watson, 1980; Polich, 1997).

Research using EEG is interesting, but it is likely to be superseded by other techniques, simply because they can provide a more detailed insight into the workings of specific sections of the ageing brain. Computed Tomography (CT
scan) is in essence an X-ray of a fine cross-section of the brain. It thus provides a view of the structure of the brain. An advance on this is the Magnetic Resonance Image (MRI scan) which can also provide images of cross-sections of the brain (or other body parts) and can also construct three-dimensional images of components of the brain (which the CT scan cannot do). The techniques are ingenious and very adept at detecting fairly large-scale anomalies, such as tissue atrophy or tumours. They have thus not surprisingly been used in analysing the brain structure of patients with dementias (see Chapter 6). However, the level of detail provided by scans (although improving constantly) is still insufficient to detect anything but fairly gross changes in non-dementing ageing. Positron Emission Tomography (PET) works on a different principle. It measures how the brain metabolises a (mildly) radioactive solution injected into the bloodstream. The more active an area of the brain, the greater its metabolic rate, and the more of the radioactive solution which will be used. This can be detected using a suitable scanner. Thus, whilst CT and MRI measure the brain’s structure, PET measures the brain’s level of activity (though still in its infancy at the time of writing, a new method called the fMRI (functional MRI) measures structure and level of activity and is likely to supersede PET, as it is both more detailed and less invasive). Conclusions from studies using such scans are nearly unanimous in noting that age-related declines in brain mass and metabolism are correlated with decrements in intellectual and memory performance (Albert and Stafford, 1988; Bakker et al., 1999; Metter, 1988; Woodruff-Pak, 1997). However,

WHAT IS AGEING? / 41
the area is still one of promise rather than total fulfilment. As techniques improve, greater precision and reliability of findings (researchers sometimes disagree on the location of changes within the brain) will strengthen the case for scans.

Summary and overview

Ageing as a widespread phenomenon is confined to twentieth century industrialised nations, resulting from lower infant mortality rates, and improvements in health care and lifestyle in earlier adulthood, rather than any intrinsic improvements in the way humans age. There is no single reliable measure of ageing – most gerontologists, as a rule of thumb, take an age of 60 or 65 years as indicating the onset of ‘old age’. About this age, declines in many physical and psychological processes (which have been taking place for most of the adult lifespan) first become readily apparent. There are many suggested causes of physical decline, which may be grouped under the larger headings of wear and tear theories (parts of the body gradually ‘wear out’ with use) and the cytologic theories (that the body ages through exposure to toxins, including metabolic waste products). The disposable soma theory explains why ageing may be an evolutionally sound strategy for an individual’s genes – certainly, ageing and death from ‘old age’ are not methods of population control, as many commentators have argued in the past. Physiological ageing typically takes the form of cell loss coupled with a decline in the efficiency of the remaining cells. A consistent phenomenon is that age-related declines are greater for complex than simple processes. The general effect of physical ageing is to provide the brain (and hence the mind) with poorer support. Perceptual changes in later life can be severe to the point of handicapping many older adults. For those with less severe loss, the brain is nonetheless receiving a compromised perception of the world around it. The ageing nervous system also suffers. There is some loss of central nervous system neurons, and a decline in the efficiency of those neurons remaining.

It must be stressed that the processes of social, biological and psychological ageing do not occur independently of each other. As has been seen, changes in the physical state of the body (and the brain in particular) can have profound effects upon psychological functioning. The point is at least tacitly acknowledged by many researchers, although not often spelt out. A useful model is provided by Dannefer and Perlmutter (1990) which combines the concepts of biological, social and psychological ageing into a single framework. The researchers argue that ageing can be seen in terms of ‘physical ontogeny’ (essentially, biological ageing);

‘environmental habituation’ (the process of coming to respond to items in the

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environment automatically: i.e. without conscious attention); and ‘cognitive generativity’ (at its most basic, conscious processing of information about the self and the environment). The ageing process is made up of a combination (and interaction) of these three factors. It is argued that some aspects of ageing, such as physical ontogeny, are largely beyond volitional control, but that others (particularly cognitive generativity) are what the individual makes of them. At a basic level, this is a re-statement of the old adage that people must make the best of what they are given, but the model is subtler than this, and interested readers are advised to consult the authors’ work.

An older and consequently further developed model by Baltes (e.g. Baltes and Reese, 1984) argues that development is determined by three factors: purely environmental, purely biological, and mixtures of environmental and biological.

These influences manifest themselves through three strands of development.

Normative age-graded development (a.k.a. age-normative development) is the basic developmental pattern one would expect to find in a ‘normal’ individual (e.g. in terms of biological ageing, the onset of puberty; in terms of social ageing, the effects of retirement on behaviour). Within a particular society, the norms of ‘correct’

behaviour determine that everyone experiences these events. Normative history-graded development (a.k.a. history normative development) charts the effects of historical events which have been experienced by one age group but not others (e.g. experience of food rationing would be normal for most British people in their sixties, but would be unusual for people in their twenties). Non-normative life development measures the effects of major events unique to an individual’s life (e.g.

not everyone has experienced playing soccer or winning the Nobel Prize). The model neatly demonstrates how people’s lives are made similar by the common experiences of normative development, how identification with one’s own generation is shaped by history normative development, and how an individual’s uniqueness is shaped by non-normative development.

In short, ageing is the result of a complex mixture of factors, and in the chapters which follow, although isolated aspects of psychological functioning have been selected for scrutiny, it must not be forgotten that they form part of a wider pattern of development.

WHAT IS AGEING? / 43

Suggested further reading

Schaie and Willis (1991) can be recommended as a general introductory text, as can Perlmutter and Hall (1992). However, note that both are American and some of the examples used may be confusing to British readers. Two British texts may be of interest. Bromley (1988) is a general textbook, comparatively cheap, well-written, and provides a solid (if now slightly dated) overview. The disadvantages are a paucity of references and an assumption that the reader is already familiar with basic medical and psychological jargon. Stokes (1992) is readable, and has a different format from many texts. It also veers towards considerations of the impact of ageing rather more than other books in this list. This may be advantageous for some readers. Corso is the acknowledged authority on perceptual processes in older adults, but much of his work is steeped in technical jargon. Slightly more approachable is the collection of papers on visual perception (including one by Corso) edited by Sekuler et al. (see reference for Carter, 1982). A good overview of neurophysiology and neuropsychology in later life is provided by Woodruff-Pak (1997). A shorter text is by Selkoe (1992) in a Scientific American article. A more advanced general text is the Handbook of the Psychology of Aging, edited by Birren and Schaie (1990). Chapters 1–3
are particularly relevant to this chapter. The book is a flagship of gerontological scholarship (however, it is also expensive, at least in the UK). Economic, social and demographic aspects of ageing are well served by the literature. Binstock and George (1990), Jeffreys (1989) and Johnson and Falkingham (1992) may be of value to interested readers.

chapter 2

Measuring intellectual
change in later life

Intuitive beliefs about ageing and intelligence

Most people, if asked to describe the effects of ageing on intelligence, would judge that stereotypical older adults have more knowledge, but are slower at thinking things through. In short, ageing is popularly characterised as an increase in wisdom at the expense of a decrease in wit. For example, Berg and Sternberg (1992) found that when asked to describe an ‘exceptionally intelligent person’ of 30, 50 or 70, participants tended to emphasise ‘ability to deal with novelty’ in younger people and stress ‘competence’ in older adults. This reflects the finding that young and middle-aged adults have a greater tendency than older adults to associate ‘wisdom’

with later life (Clayton and Birren, 1980). A problem with attitude studies is that it is sometimes difficult to judge if everyone is using the same mental models in making their judgements (e.g. is the ‘very intelligent’ older person what the hypothetical very intelligent younger person will turn into?). A more revealing insight into everyday concepts of ageing and intelligence is perhaps to be gained from studies of the works of art. For example, painters and sculptors have conditioned people to accept that a depiction of a healthy older man looking pensive is automatically a representation of the epitome of wisdom, be it temporal or spiritual. It is very difficult for anyone raised in a Western culture to think of a philosopher, saint or even God, as anything other than an older man (long white beard optional). Paradoxically, older people are simultaneously portrayed as being slow thinking and dull witted. The elderly person, doddery of mind and body, has been the butt of jokes from Chaucer to television situation comedy. Dogberry’s famous adage in Much Ado About Nothing that ‘when the age is in, the wit is out’ expresses the guiding spirit for centuries of ageist humour.

45

46 / THE PSYCHOLOGY OF AGEING

This conflicting view is neatly encapsulated in Dewey’s paradox of ageing, which states that ‘we are ... in the unpleasant and illogical condition of extolling maturity and depreciating age’ (Dewey, 1939). However, popular opinion is not necessarily synonymous with scientific fact. Is there any proof that different aspects of intelligence are differentially preserved?

Crystallised and fluid intelligence

When psychologists began to consider the issue in the early years of this century, it was generally felt that ‘intelligence’ was a unitary skill. In other words, no matter what type of intellectual task was set, be it verbal, numerical or visuo-spatial (i.e.

shapes and figures), the same basic ability dictated a person’s performance. This was christened g (for ‘general intelligence’) by one of the founding fathers of intelligence testing, Charles Spearman. The term ‘g’ or ‘Spearman’s g’ is still in use, although it is now generally used more loosely, to describe overall ability or score on a battery of intellectual tests which have assessed a variety of intellectual skills. Most researchers now reject the more rigid definition of g, arguing that ‘intelligence’ is composed of several interrelated skills. What these are is still open to debate (see Eysenck and Kamin, 1981; Kail and Pelligrino, 1985; Rebok, 1987). However, perhaps the most widely accepted theory has been the hierarchical approach (Cattell, 1971). This argues that all intellectual skills make use of a general intellectual ability, but they also call upon more specialised skills, depending upon the needs of the task at hand.

Cattell (1971) and Horn (1978) identified two of these specialised skills, and called them crystallised intelligence and fluid intelligence.

Crystallised intelligence measures the amount of knowledge a person has acquired during his or her lifetime. Usually it is measured by simple direct questions, such as asking the person to define obscure words (e.g. ‘what is the meaning of manumit?’), or to answer ‘general knowledge’ questions (e.g. ‘what is or are the Apocry-pha?’). The questions can also ask a person to solve problems based on their existing knowledge. They can be practical (e.g. ‘what do you do if you cut your finger?’) or moral (e.g. ‘why should we pay our taxes?’). Such questions can only be answered correctly if one already has the necessary information in one’s head and can retrieve it. One cannot create definitions of words or knowledge of sticking plasters, antisep-tics, taxation structures or fiscal policy on the spur of the moment. Fluid intelligence tests, on the other hand, draw on acquired knowledge as little as possible, and measure what might be defined as the ability to solve problems for which there are no solutions derivable from formal education or cultural practices. In other words, it is the

MEASURING INTELLECTUAL CHANGE IN LATER LIFE / 47
ability of the person to solve novel problems. The most commonly used method is to ask a person to identify a rule governing a group of items (verbal, numerical or visuo-spatial) and then provide the next one in the series: A C F J ?

or to spot the odd one out:

245 605 264 722

Typically, fluid intelligence tests have a time limit imposed on them so that, to be proficient, a person must not only be accurate, but fast as well.

There is also the measure of overall intelligence called (not surprisingly) g, which, according to Horn and Cattell’s framework, is the aggregate of fluid and crystallised intelligence scores. In the next section it will be examined how these skills change (if at all) with age.

Age changes in general intelligence (g)

Early studies (circa 1900–1930) of the effects of ageing on intelligence brought discouragement to anyone older than their late twenties. The typical finding was of the classic ageing curve – intelligence test scores rose to a peak in early adulthood, before beginning a steady downward decline around the person’s thirtieth birthday, though verbal skills were typically unaffected (see Rebok, 1987; Thompson, 1997).

However, this finding was based upon flaws in the methodologies used (in fairness to the early researchers, some of them recognised the potential problems; see Thompson, 1997). Principal amongst these was an over-reliance on cross-sectional studies. These are experiments in which groups of people of different ages are tested and compared at the same point in time. However, if the researcher finds an age group difference, he or she cannot be sure how much of an age group difference is due to age per se, and how much is due to the effects of different educational and socio-economic backgrounds. The last hundred years have seen an enormous improvement in health care and standards of living. Younger adults may therefore outperform older adults not because they are less old, but because they are healthier, have had more (and better?) education, and have been brought up in a culturally

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richer world. A difference due to generational differences in background and upbringing rather than ageing per se is called a cohort effect.

There are several ways of compensating for the cohort effect. One is to try to match the age groups for level of education, socio-economic class, and so forth; in other words, try to ensure that the only difference between them is their different ages. This is problematic, because it is practically impossible to match large numbers of people in this way, and for many forms of analysis, large numbers are de rigeur.

Again, there are some factors which simply cannot be matched, such as different historical and cultural experiences. A related method is to compare younger and older adults, and then statistically adjust their scores to account for the cohort differences which can be calibrated. This is best illustrated by example. Suppose it is found that there is a difference in test scores between an older and younger group, but that the two groups also differ in how many years of formal education they received (highly likely, because the minimum age at which a child can leave school has been raised incrementally over the last hundred years). The difference may be due to age, but it could also be due to education level (variables which may distort results in this manner are called confounding variables). There are a variety of methods of statistically adjusting the figures to take account of confounding variables; in this instance, a statistical technique would be used to discover if there is still an age difference after the proportion of the difference due to different education levels has been accounted for. There are three possible outcomes of this procedure – either there will be no change in the finding (i.e. differences in education levels are coincidental: they have no influence on the difference in test scores); or the difference is removed (i.e. the age group difference was coincidental: it was all due to differences in education levels); or the difference is lessened, but a significant (if smaller) difference remains (i.e. education level accounts for some of the age group difference, but not all of it).

It has been known for several decades (e.g. Ghiselli, 1957; Latimer, 1963) that when confounding variables are controlled for in this way, the age difference is typically diminished but not removed (see Stuart-Hamilton, 1999b). This will be considered in detail in Chapter 7, but for the moment, it is sufficient to note that at least some of the age differences found in a cross-sectional study will be almost inevitably due to cohort effects.

Although attempting statistically to remove cohort effects from a longitudinal study can be effective, it is practically impossible to remove all cohort effects, simply because some of them cannot be measured (as stated above, how can one quantify differences in historical epochs?). Another method of measuring ageing change can cope with this problem. This is the longitudinal study, in which the same group of

MEASURING INTELLECTUAL CHANGE IN LATER LIFE / 49
people are tested at one age, then retested as they get older (typically at fixed intervals of time). Suppose one wished to compare the difference between 20- and 70-year-old people on a test. Using a cross-sectional method, groups of 20- and 70-year-old people would be found and tested and their results compared. In a longitudinal study, a group of 20-year-old people would be tested, then retested 50
years later when they reached 70, and their test scores on the two occasions would be compared. There are considerable advantages to the longitudinal over the cross-sectional method. The most important is that it escapes the problems of cohort effects mentioned earlier. If an age difference is found in a longitudinal study it cannot be because the older and younger groups differ in their upbringing, since the two groups are composed of the same people. An age difference in these circumstances can only be due to growing older. When longitudinal studies have been run, then g is found to be preserved until at least middle age, and usually far longer (e.g. Bayley, 1968; Owens, 1959; Purdue, 1966; Schaie and Hertzog, 1986). Thus, a large component of supposed age differences in early studies was in fact attributable to cohort effects.

However, longitudinal studies are not without their problems. First, there is the thorny issue that a longitudinal study may only be informative about the particular cohort which is studied (e.g. following a group of people born in 1920 across their lives, may uncover a different pattern of change from a group born in 1940). In other words, having removed one form of the cohort effect, we are immediately saddled with another permutation of the problem. A second issue arises from the fact that many volunteers drop out of longitudinal studies. In some cases, this is because they move to areas too geographically remote for the researchers’ travel expenses. A more serious worry is that many volunteers quit for motivational reasons. No matter how hard researchers try to explain to the contrary, most participants in experiments seem to regard psychological tests as a competition. Therefore, if a volunteer perceives him- or herself to be worsening in intellectual performance, then he or she may be less willing to be retested. This means that as a longitudinal study progresses, the ‘declining’ participants drop out, leaving a rump of ‘well preserved’ volunteers (the drop-out effect). For example, Riegel and Riegel (1972) demonstrated that people who refused to be retested in a longitudinal study had significantly lower test scores than those who remained, a finding echoed by Siegler and Botwinick (1979). This problem is compounded by the fact that those participants who remain often significantly improve in their performance on the tests employed (Salthouse, 1992b). To rebut the obvious criticism, this is not because the participants remember the answers from the last time they did the test (at different sessions they are given ‘parallel ver-

50 / THE PSYCHOLOGY OF AGEING
sions’ of the test, which use different questions whilst having the same general format and level of difficulty). Instead, the problem is probably due to several factors.

Participants may become test wise: in other words, they are increasingly at ease with the test procedures (and hence perform better), have increased general awareness of the ways in which psychological tests operate, and so forth. For whatever reason they occur, the result of these flaws is that the longitudinal method may underestimate the effects of ageing (whilst the cross-sectional method probably exaggerates them).

One method of side-stepping the problems of the two approaches is to combine them in a technique called the overlapping longitudinal study. This essentially involves testing several age cohorts on one occasion, then retesting them at regular intervals thereafter. To take a simplified example: Suppose that at the first test session there are groups of 50-, 57-, 64-, and 71-year-old people. They are tested, and their performances at Session 1 can be compared in the manner of a traditional cross-sectional study. At regular intervals thereafter (for the sake of argument, let us say every 7 years), the participants are retested. Thus, at Session 2, the 50-year-old group is now 57, the 57-year-old group is now 64, and so forth. The age groups at Session 2 can once again be compared in a cross-sectional manner, but in addition, the members of each group can be compared with their younger selves, as in a longitudinal study (e.g. the people who are 71 at Session 2 can be compared with their 64-year-old selves at Session 1).

Table 2.1 - A conceptual table illustrating the
overlapping longitudinal study

Session 1

Session 2

Session 3

Session 4

Session 5

Cohort 1

50

57

64

71

78

Cohort 2

57

64

71

78

85

Cohort 3

64

71

78

85

92

Cohort 4

71

78

85

92

99

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However, there are further advantages to the overlapping longitudinal method beyond simply combining cross-sectional and longitudinal methods. Consider Table 2.1, which conceptually represents this imaginary study. As can be seen, as the study progresses, the younger cohorts will become the ages the older cohorts were earlier in the study. For example, at Session 4, Cohort 1 will become the age Cohort 4 was at Session 1. Armed with such information, it is possible to gauge and control for cohort effects. Take the following (intentionally simplified) example. Suppose that at Session 4, it is found that Cohort 1 has scores 20 per cent higher than Cohort 4. Does this mean that ageing from 71 to 92 will result in a 20 per cent loss in ability, or is this change due to a cohort difference? To answer this, we can consult Cohort 4’s scores on Session 1, when they were the same age as Cohort 1 is at Session 4. Suppose we find that Cohort 4 when aged 71 had scores only 5 per cent lower than when aged 92. We now have two measures of ageing decline – the longitudinal method says the change is 5 per cent, the cross-sectional method says the change is 20 per cent.

Armed with such information, it is possible to tease apart how much of ageing change is due to ageing per se, and how much is due to cohort differences.

Adopting this design (though in a more complex and erudite form – the above is a simplified illustration), Schaie and colleagues conducted the Seattle Longitudinal Aging Study (e.g. Schaie, 1983; 1994). In 1956, a group of people aged between 20 and 70 were tested and then retested at seven-yearly intervals thereafter (i.e. in 1963, 1970, 1977, and so forth). Periodically new participants have been added.

The principal test used was the Primary Mental Abilities Test or PMA (Thurstone, 1958). This is a test battery (i.e. a collection of tests with a common theme – in this case intelligence – although each test measures a different facet of the skill). The authors of the PMA claim that it measures five distinct abilities: number (basic arithmetic and number skills); reasoning (logical deduction); space (visuo-spatial skills); verbal meaning (knowledge of semantics); and word fluency (efficiency at producing words related to an example). However, by cross-checking the figures in a manner conceptually similar to the above example, Schaie has demonstrated that part of the age difference is due to cohort effects. However, having allowed for this, a significant decline becomes apparent when people reach their mid-sixties. It would thus appear that the social age concept (see Chapter 1) that ‘old age’ begins in the sixties may have some empirical support. Equally, it rejects the earlier findings that appreciable ageing decline begins before middle age.

An important caveat must be made at this point. It should be noted that what changes with age is the raw score on an intelligence test (quite simply, how many answers a person gets right). The intelligence quotient (IQ) does not alter particularly with

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age. This is because IQ is calculated by converting the raw score into a measure of how intelligent a person is relative to the rest of his or her age group, and not adults of all ages. Generally, an individual remains at roughly the same level relative to his or her age peers throughout the lifespan. For example, if a person starts life as a young adult of average IQ, he or she will probably end life as an older person of average IQ.

However, their raw score will have declined (it follows from this that to be classified as ‘average IQ’ requires a lower raw score the older one is). It is important to note this because researchers have a tendency to use ‘IQ’ as shorthand for intelligence. However, statements such as ‘IQ declines in later life’ are, strictly speaking, misleading.

Age changes in fluid and crystallised intelligence

So far intelligence has been considered principally as a general measure. However, what of the crystallised and fluid skills discussed earlier? Is it the case, as was mooted above, that fluid intelligence declines whilst crystallised skills are unaffected by the ravages of time? An often-cited study by Horn and Cattell (1967) supports this notion, since they demonstrated an age-related decline in fluid intelligence, whilst crystallised test scores remained stable. However, the researchers probably underestimated the age when the decline started, perhaps because of cohort effects.

Schaie’s Seattle data found that components of the PMA which were crystallised remained relatively unaffected by ageing, whilst fluid skills began to decline appreciably in the mid-sixties. Subsequent studies have almost universally supported Schaie. For example, Cunningham, Clayton and Overton (1975) demonstrated that younger people had significantly higher scores on a common test of fluid intelligence (Raven’s Progressive Matrices) than did older people, whilst age differences on a crystallised test of vocabulary were relatively insignificant. Hayslip and Sterns (1979) found similar results using a battery of fluid and crystallised tests.

An analogous point is made by Salthouse (1992a). He reviewed a number of studies of performance on fluid intelligence tests, and re-tabulated the scores of the older participants. He found that compared with younger adults, the older people were an average of 1.75 standard deviations [see Glossary] below the mean of the younger group (figures extrapolated from Salthouse, 1992a, Table 4.2, pp. 175–176). This is a very large difference. To put it in perspective: if a child or teenager scored 2 standard deviations below the mean for their age group on an intelligence test, then he or she would be considered to be potentially in need of remedial education. Were the average older adult several decades younger, he or she would be bordering on candidature for special education. This point is a dramatic one, and is surprisingly infrequently aired

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in the research literature. We shall return to it in Chapter 7. However, it is important to state two caveats at this point. First, the studies used by Salthouse are largely cross-sectional. Therefore, part of this considerable age gap may be due to cohort effects. Second, different studies using the same test have produced rather variable results. For example, the PMA Reasoning test has, in different researchers’ hands, yielded effects ranging from -1.62 standard deviations (s.d.s) to -5.19 s.d.s.

Accordingly, these findings must be treated with caution.

It is important to stress that cohort effects can exaggerate cross-sectional measurements of age differences. For example, Storandt (1976) tested older adults on a component of a widely-used intelligence test battery called the Wechsler Adult Intelligence Scale, or WAIS. The particular measure she used was the digit-symbol test. This requires participants to match up digits to printed symbols according to a preordained code (e.g. if one sees a square, write a 2 underneath it, and similarly, a tri-angle equals 3, a rectangle equals 4, etc). There is a time limit of 90 seconds, during which the participant must match up as many symbols as possible. The test clearly is centred on the ability to remember and use a coding system, but because of the time constraint, it also requires rapid writing. However, older people are generally slower at writing because of physical problems (e.g. arthritis, rheumatism, simple general weakening of muscles and joints). Thus, they may perform relatively badly at the task, not because of a failure of mental processing, but because they cannot write down the answers quickly enough. To see how much time older people were losing through writing, Storandt measured how many symbols people could copy within 90 seconds, and took this as the index of writing speed. This was compared with the performance on the test itself, and Storandt was able to demonstrate that about half the age difference was due to writing speed. This clearly demonstrates that physical limitations may exaggerate psychological differences, but it should be noted that a psychological difference nonetheless remained (a finding echoed in a similar study by Tun, Wingfield and Lindfield, 1997). Indeed, even when given as long as they wanted to perform a fluid intelligence test (Storandt, 1977), or increasing the test print size to overcome eyesight problems (Storandt and Futterman, 1982), older people still performed significantly worse then younger controls.

To further confuse matters, performance on crystallised intelligence tests is not as immune to ageing as it may first appear. For example, Core (unpublished, cited Rabbitt, 1984) found that older adults took significantly longer to respond to questions on a crystallised intelligence test (the Mill Hill Vocabulary Test). Had a time limit been imposed on the test (significantly, crystallised intelligence tests are generally not against the clock), then older people would have performed significantly less

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well than younger controls. Hence, to a certain extent, the absence of an age difference on a crystallised intelligence test is because researchers have decided not to put a stopwatch to the task. Again, Botwinick and Storandt (1974) demonstrated that although there was no age difference in performance on the WAIS vocabulary subtest, the answers given by older people were less precise. However, the test marking criteria were sufficiently lax for this difference to go unchecked. Other researchers, using different crystallised tests, have found an age decline without any revision of marking scales (e.g. Kaufman and Horn, 1996).

There are further examples in this chapter (and elsewhere in this book) where crystallised skills can be shown to decline with age. This is supported by Meacham (1990) who argues that ‘the essence of wisdom is not in what is known but in how that knowledge is held and put to use’ (p. 188). This implies that once one moves beyond a straightforward recital of stored information to any form of interpretation, then a decline is at least possible. However, it cannot be automatically concluded from this that crystallised skills are necessarily fluid intellectual skills in disguise. There is considerable evidence that the two skills behave in somewhat different ways. For example, as Horn and Cattell originally argued, fluid intelligence tests are more strongly correlated with physical condition (e.g. pulmonary function; Emery et al., 1998).

Again, decline in crystallised skills, where observed, has tended to be far less severe than for fluid skills (see Lindenberger and Baltes, 1997), and longitudinal changes in the variability between people’s crystallised test scores tends to be less than for fluid scores (Christensen et al., 1999). Furthermore, in at least the early stages of dementia, certain crystallised skills may be preserved (thereby giving a reasonable indicator of pre-illness level of intellectual functioning) when fluid skills have already severely deteriorated (see Carswell et al., 1997; Raguet et al., 1996). Crystallised skills may not be ageing-proof, but they are perhaps rather more resistant than fluid skills.

Wisdom

It is also important not to confound crystallised intelligence with wisdom. The terms have been used interchangeably by some commentators (including this author). Because wisdom can be understood to mean ‘worldly knowledge’, the usage is not unreasonable. However, some researchers prefer to use the term in a more specific manner. Unfortunately, there is little direct concordance between definitions (see Shea, 1995; Sternberg, 1996), with different researchers pursuing different aspects of what is after all a rather nebulous term. At one level, there have been attempts to define wisdom in terms of psychometric parameters. For example,

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Sternberg has attempted to correlate it with various essentially intellectual traits (see Sternberg, 1996, 1998). In contrast, psychoanalytic approaches have attempted to link it with a lifetime of experiences of personal conflicts and resolutions (see Shea, 1995). However, underlying many of these arguments is perhaps a simpler concept –
that of ability at resolving real life problems. For example, Sternberg (1998) predicates his model of wisdom on the concept that it is essentially about finding balance between conflicting forces. Baltes and Smith (1990) define it in terms of sagacity of judgements about real life problems. Chandler and Holliday (1990), based upon interviews with members of the public, synthesise a similar view of providing good advice, with the additional considerations of being competent and socially skilled in doing this. In most instances, researchers stress that wisdom is very much linked to ‘real world’ problems where pragmatic considerations may play as important a role as pure logic (the goal of many acts of wisdom is to resolve an issue rather than solve it).

Empirical evidence on wisdom generally finds a reasonably strong correlation with intelligence, tempered by personality traits, but with a significant proportion of measurement independence (e.g. Staudinger, Lopez and Baltes, 1997; Staudinger et al., 1998). In other words, although wisdom is in part a product of a person’s personality and intelligence (which, given its definition, would not be surprising), it is also in part independent of these factors (i.e. it is not just another way of describing g).

Predictably, researchers have also found that wisdom is a beneficial ability, and is strongly related to, inter alia, life satisfaction in older people (Ardelt, 1997; 1998).

Individual variation

It is important to note that the above findings describe what happens to age groups as a whole – however, there is considerable variability between individuals of the same chronological age. For example, Rabbitt (1984) divided a group of 600 people aged 50–79 into age decades (i.e. fifties, sixties and seventies) and tested them on a set of crystallised and fluid intelligence tests. The groups showed no difference on crystallised tests, but there was a significant ageing decline on the fluid measures. The instinctive supposition is that this means that everybody in the older groups was getting worse. However, this is not what was happening. Most people’s scores declined with age, but not all. Thus, Rabbitt found that the best and the worst scores in each age group were the same (i.e. if one found a person in the fifties group with a very high score, a person could be found from the seventies group who could match it). The age difference was coming from a downward shift in a majority but not all of

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the people tested. In more technical language, there was an increased skew in the older groups’ scores. Rabbitt estimated that between 10 and 15 per cent of older adults were retaining their youthful level of intellectual skills. Salthouse’s review a few years later (Salthouse, 1992a) found smaller proportions of ‘well preserved’

older adults. Whatever the precise figure, the important point is that a decline in fluid skills is not inevitable for everyone.

Subsequent research by Rabbitt (e.g. Rabbitt, 1993) and others (e.g. Barton et al., 1975) has demonstrated that variability in test scores is greater for older than for younger people on a variety of cognitive measures, such as reaction times (see below) and measures of memory. A literature review by Morse (1993) also records similar findings on changes in variability in later life. This means that amongst themselves, older adults differ more in their performance than do younger people, and hence, in this context, it is harder to justify talking about a ‘typical’ older person than it is to talk about a ‘typical’ younger person. Furthermore, it appears that some fluid skills may be better preserved than others, and that the pattern of preservation varies between individuals (thus, one person may have skills A,B, and C well preserved, and D, E and F may be declining, whilst for another person the opposite pattern may be true). Rabbitt observes that these changes might be linked to physical changes in the brain (e.g. they may reflect disproportionately heavy losses of neurons in particular lobes, in the hippocampus, etc). This theory echoes that of ‘critical loss’ discussed in the ‘terminal drop’ model below.

The general findings on ageing changes in intellectual skills are not disputed.

However, the potential distortion from cohort effects, and the fact that individuals do not necessarily behave as one, means that it is harder to determine the precise size of

‘genuine’ ageing effect than might first be supposed. In theory, practically any cohort effect can be resolved by use of a longitudinal study. However, this is usually an impossible course of action for obvious practical reasons. The length of time needed properly to run a longitudinal study means that, problems of drop-out effects aside, they are expensive, and (obviously!) take decades to run. This is too long to wait every time one wants the answer to a simple question (forget H.G. Wells or Back to the Future – the best use of a time machine would undoubtedly be to run longitudinal studies on an economic footing). To all intent and purposes, researchers are ‘stuck’

with cross-sectional studies and the attendant problems of controlling for cohort effects and other confounding variables.

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The terminal drop model

So far (with the exception of Rabbitt’s work), changes in intelligence have only been considered in terms of the average performance of different age groups. How representative of the individual is this group performance? It is known that if the average scores for age groups are taken, then these inexorably decline with increasing age, but the rate of decline is fairly gentle. Is this true for individuals as well – in other words, if we were regularly to measure the intelligence test scores of an older person, and plot them on a graph, would we see a similar gentle decline? The answer in some cases appears to be ‘no’. Some older people display a very rapid decline in scores in the months before they die. This phenomenon has the moribund title of terminal drop (Kleemeier, 1962; Riegel and Riegel, 1972). The terminal drop model argues that individuals maintain the same level of performance until a few months or years before death, when their abilities plummet, as if their minds suddenly ‘wind down’ in preparation for death.

An immediate counter-argument to this is that if the individual decline is so sudden, why does the group decline appear relatively gentle? The answer is quite simple.

The probability of dying rises from middle age onwards. Therefore, the older the age group, the greater the proportion of its members in the terminal drop stage, and hence the lower the average intelligence score for the group as a whole. However, because the proportion of ‘drop’ individuals rises fairly gently across age groups, the overall group average likewise only declines gradually. Thus, the terminal drop will not reveal itself in group averages, but only when individuals are examined.

Kleemeier (1962), working on longitudinal data, found that if on retesting, a participant showed a large drop in intellectual performance, then there was a high probability that he or she would be dead within a short space of time. Similar evidence was provided by Riegel and Riegel (1972). They tested a group of middle-aged and older volunteers, and then retested them 10 to 20 years later. The researchers found that the volunteers who had died before they could be retested had had significantly lower scores at the initial test session. Every longitudinal study has similarly reported the terminal drop phenomenon (Jarvik, 1983), although the magnitude of the effect varies from study to study and to a certain extent is dependent upon the method of statistical analysis used (Palmore and Cleveland, 1976).

Jarvik and colleagues developed the terminal drop model to include the concept of critical loss (e.g. Jarvik and Falek, 1963; Jarvik, 1983). This argues that if over a period of time (10 years in the original study) there are declines in abilities on intelligence tests which exceed certain boundaries, then the probability of dying within a short period of time is dramatically increased. The extent to which a skill

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may decline before it is considered critical very much depends upon the skill in question. For example, Jarvik argued that the ability to detect verbal similarities can decline by up to 10 per cent without cause for concern. However, any decline in vocabulary size was counted as a critical loss. Blum, Clark and Jarvik (1973) conducted a longitudinal study on 62 older volunteers, and found that 15 of them had suffered a critical loss. Within five years of retesting, 11 of these were dead (compared with 5 of the other volunteers). Whilst accepting the general concept of critical loss, other researchers have disagreed with Jarvik et al. regarding what constitutes a critical decline. For example, Botwinick, West and Storandt (1978) found that changes in verbal abilities did not predict terminal drop, whilst worsening abilities on paired associate learning (remembering which items have been previously seen together) and psychomotor skills (very loosely, mental skills with a physical skill component) did. In complete contrast, Siegler, McCarty and Logue (1982) found that verbal skills were the best predictors of the probability of imminent death. To complicate matters further, Reimanis and Green (1971) found that the total score on the WAIS was the best predictor. In other words, although researchers agree that something must be declining in the terminal drop phase, nobody seems quite sure what it is.

A further problem with the terminal drop model is that it only appears to apply to younger older people (i.e. those aged under about 75). For example, Jarvik (1983) and Riegel and Riegel (1972) reported that the deaths of participants who had reached their mid-eighties or more were not predicted by their test scores. Similarly, White and Cunningham (1988) demonstrated that a drop in intellectual performance (in this case, of vocabulary scores) only predicted death if: (a) the person was aged under 70, and (b) he or she had been tested within two years before their death. Why should this curious state of affairs occur? The reason is probably as follows. Death in younger old age is usually due to a specific illness or to an accident (often in part cause by a physical decline, such as sensory impairment). Such a precipitous decline presumably has a similarly deleterious effect on psychological functions. Older elderly people (i.e. those aged over 75) have (obviously!) survived these events, but have considerably frailer bodies, and death may occur not so much from disease, as a steady decline in everything, until one physiological system reaches the point of col-lapse. However, this decline occurs slowly and reasonably randomly, and thus is unlikely to be reflected in a sudden drop in psychological skills. For example, Berkowitz (1964), in a longitudinal study of older men, reported that acute illness leading to death caused bigger declines in intellectual scores than chronic conditions.

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Hence, terminal drop certainly exists, but interpretations of it must be cautious, since researchers are undecided on which skills are involved and also, the phenomenon is probably restricted to relatively young older people.

Disuse theory

Several researchers have found that physical exercise can improve certain aspects of ageing intellectual performance. For example, Hawkins, Kramer and Capaldi, (1992) demonstrated that a ten week exercise programme resulted in a significant improvement in attention tasks, and that in some instances, this was disproportionately greater for older than younger participants. Powell (1974) found cognitive improvements in older institutionalised patients given an exercise regime. Again, people who maintain a reasonable level of physical fitness appear in general to change less over time on indices of intellectual performance, particularly fluid intelligence (Bunce, Barrowclough and Morris, 1996; Emery et al., 1998). There are many reasons why physical exercise might have a beneficial effect on the intellect. A healthy body is likely to function more effectively (particularly the cardiovascular system) and, as was seen in Chapter 1, a healthy body can enhance neural and hence intellectual functioning. Again, an older person who feels fit and healthy is also more likely to have greater confidence in what they are doing, and hence have a higher motivation to do well at mental tasks. Physical exercise and well-being is thus probably a ‘good thing’. However, what of mental exercise?

A commonly-used expression is use it or lose it’. The more refined psychological term is disuse theory – the belief that age-related declines are attributable to a failure to use skills, so that eventually they fall into a decline (see Milne, 1956). The theory is not easy to prove or disprove. Finding that older people practise a skill less, and that the level of performance on that skill is lowered is ambiguous. The skill may be worse because of lack of practice. However, the skill may have worsened, causing the older person to lose the motivation to continue practising it (motivation is known to adversely affect older participants in a variety of tasks – see Perlmutter and Monty, 1989). Or, the skill could have worsened by itself, in spite of practice. Studies of older very well practised individuals have almost always found that there is a decline in at least some related skills spite of regular practice. For example, architects and airline pilots have shown age-related declines on spatial tasks in spite of using spatial skills every day of their working lives (Salthouse, 1992a). Before readers panic that older architects are therefore unsafe to design buildings or older pilots unsafe to fly, it

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should be stressed that these declines are relative to younger architects or pilots – in absolute terms, their skills are still high.

However, it would be wrong to draw too bleak a conclusion from these findings.

The experiments cited above use relatively abstract laboratory tests. If one considers more realistic situations, then the age difference is often less. Although older people may be slower and less accurate at some ‘basic’ skills, their experience may be able to compensate for this. For example, Charness (1981) studied older chess players and found that they were able to play chess as well as younger adults. However, what was remarkable was that the older players often showed quite serious declines in skills which should be essential to good chess playing, such as memory. Charness found that the older players compensated for this loss by having a greater fund of experience. Because they had played (literally) thousands more games than younger opponents, they were able to tap a greater store of knowledge. Thus, when faced with practically any sort of game, they had probably been in the same situation many times more often than younger players. Greater experience thus compensated for loss of more basic skills. The same researcher found analogous results in an earlier study of habitués of bridge (Charness, 1979). Similarly, Salthouse (1984) compared older and younger typists. He found that the older typists generally had slower finger movements and reaction times, but showed no difference in typing speed. This was because the older typists planned longer sequences of finger movements than younger typists (with less experience) could manage. Thus, although it took an older typist longer to move a finger to a key, the move towards that key started earlier because they looked further ahead (in essence, younger typists were starting later in their sequences of finger movements and then catching up with the older typists). Bosman (1993) adds that this only applies to older typists who regularly practised their skill.

A caveat to this is provided by a study by Westerman et al. (1998) of older and younger participants who were all practised in word processing. The researchers found evidence for a compensatory strategy, but also noted that amongst the more skilled older participants, their abilities were associated with possession of high levels of basic cognitive capacities rather than integration of sub-skills into an overall strategy.

This implies a bigger role for basic skills than other compensation studies have suggested, but it should also be noted that Westerman et al.’s sample was of people who had ‘over 100 hours of experience in using a word processor’ (p. 583) as opposed to the years or decades of experience of participants in some other studies.

Practice may not only preserve existing skills, but also revive supposedly lost or declining ones. For example, Plemons, Willis and Bates, (1978) demonstrated that training in taking fluid intelligence tests could boost the test scores of older partici-

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pants. Furthermore, this seemed generally to enhance performance of intellectual tests, suggesting that the training made participants more test wise. These findings are echoed by other researchers (e.g. Baltes and Willis, 1982; Kermis, 1983; Rebok, 1987). Salthouse (1992a) criticises these studies because often there have been inadequate control groups, and/or the success of the training has been judged on too narrow a range of tests. Again, he (and other commentators) has suggested that training may not affect the root skill, which remains in decline, but instead may offer new strategies to cope with the problem. This is analogous to taking a painkiller to mask the pain of toothache – it does not cure it, but it enables one to cope. From a practical viewpoint, this argument may seem relatively unimportant (why worry if it helps older people cope?), but the theoretical considerations are of course not trivial.

Reaction times

The reaction time or RT is a measure of how long it takes a person to respond to the appearance of a stimulus: the lower the reaction time, the faster the person is responding (and vice versa). Obviously, having lower reaction times is advantageous.

Faster reactions will aid a sports player and may mean the difference between life and death to a car driver. Other examples of reaction times are less dramatic but more central to everyday life. For example, the speed at which one can think of the answer to a question is an example of a reaction time, as is the time taken to recognise a voice, a face or a familiar picture. Wherever there is the perception of something and a response to it, there is a reaction time. Thus, in one sense, the reaction time is the measure of the time gap between reality and one’s perception of it. Most research on reaction times has confined itself to rather more mundane considerations, such as the time taken to make a simple response to a simple stimulus. Classical reaction time experiments adopt two basic formats. The first is the simple reaction time (SRT) study. This is a measure of how quickly a person responds when there is only one stimulus and only one response allowed. This is typically tested by requiring a person to press a button every time a light flashes (or an analogous condition). The delay between the signal and the response is the reaction time. The second measure is the choice reaction time (CRT). In this instance, the participant is presented with an array of stimuli and a choice of responses. For example, there might be three lights and three buttons, and the participant is told to press button A if a red light flashes, B
if a green light, or C if a blue light. Participants have to give more consideration to what they see in a choice reaction time experiment, and thus responses tend to be

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slower than in a simple reaction time paradigm. Similarly, the more choices which have to be decided between, the slower the responses become.

It is very well established that reaction times get slower as people get older. According to the review by Birren and Fisher (1995, p. 329), it is ‘one of the most reliable features of human life’ (see also Lindenberger, Mayr and Kliegl, 1993; Rabbitt, 1996). This is not doubted. Nor is it questioned that if people are tested on a single occasion, older people are disproportionately slower on choice than on simple reaction time tasks. Furthermore, the age difference gets proportionately larger the more choices that must be discriminated between in a choice reaction time task (see Botwinick, 1973; Kermis, 1983; Salthouse, 1985). The simple explanation for these phenomena is that older people’s nervous systems are slower and less efficient at conducting signals, and the disadvantage imposed by the extra choices is another manifestation of the age x complexity effect (see Chapter 1).

However, beyond this fairly superficial level lie some deeper and fascinating problems. It should first be noted that much of the disproportionate age difference on choice reaction time tasks disappears if people are allowed to practise for several days; older adults remain slower across different versions of the task, but the difference becomes a constant (Rabbitt, 1980). In other words, if an older person is x milliseconds slower on a simple reaction time task, he or she will also be x milliseconds slower on a choice reaction time task. This implies that a significant proportion of the age difference may be due to ‘settling in’ to the task. Once it has become sufficiently rehearsed to be automatic (in psychological terms, this generally refers to a skill rehearsed to the point where it requires no conscious control), then age differences are less important than when the task required conscious monitoring. Hasher and Zacks (1979) argue that automatic processes are relatively unaffected by ageing, although more recent commentators (e.g. Burke, White and Diaz, 1987; Myerson et al., 1992) have found some instances where this is not the case.

A further consideration is that many researchers have only considered age difference in mean reaction times. Rabbitt (1980, 1988a,b) argues that this is misleading, since it presented the impression that older people are incapable of the fast responses of their youth. In fact, if the distribution of response speeds is considered, then the fastest reaction times of older and younger people are the same. The age differences lie elsewhere. In part they are because older adults make fewer very fast responses.

They are also due to older people making a much wider variety of response speeds, which increases the mean reaction time. This is particularly the case when reactions to errors are concerned (an error occurs when, e.g. in a choice reaction time task, the participant presses button B when the correct response was A). Participants are usu-

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ally aware they have made a mistake, and respond by slowing down on the next trial.

Younger adults then pick up speed relatively quickly, whilst older people take several more trials to return. This means that relatively speaking, younger adults ‘shrug off’ their mistakes quickly, whilst older adults are overcautious. Younger adults thus can find an optimal response speed (i.e. as fast as they can go without making too many mistakes) and stick to it, whilst older people seem to lack this level of control and oscillate far more. When the average performances are considered, this age difference expresses itself more simply as a difference in mean response times. In a more recent study, Smith and Brewer (1995) have provided similar evidence.

It is well established that reaction times correlate well with measures of intellectual performance (e.g. Ferraro and Moody, 1996), and from this emerges another interesting phenomenon. Rabbitt and Goward (1986) found that if groups of older and younger adults are matched for intelligence test scores, then there is no difference in their choice reaction times. Hertzog (1991), Salthouse (1991a) and Schaie (1989) similarly report that when the effect of speed of response is statistically controlled for, differences between age groups on intellectual tasks are significantly lowered, or disappear altogether. This implies that slowing reaction times are measuring the cause of declining intellectual skills (e.g. Eysenck, 1985; Salthouse, 1985). If two items such as intelligence test score and reaction time are correlated, there is no simple mathematical way of proving which causes the other. However, it can be logically argued that reaction times are measuring a more fundamental process (and hence an earlier stage in the chain of causation) than are intelligence tests. Very crudely, reaction times measure the speed with which neurons send messages, intelligence tests measure what is done with those messages. If older people have slower reaction times, then they have slower mental processes, and this in itself could explain much of the decline on timed intelligence test scores. However, there is more to this issue than just simple speed. In tandem with the slowing comes a lowering in the general accuracy and efficiency of the system. In part this is because some mental processes may have to be executed within a certain number of milliseconds or they decay beyond recovery – a slower system means that some processes will take longer to complete than this critical limit, and so a particular mental process cannot be completed (see Salthouse, 1996). Again, a decline in speed is the result of the general physical decline of the nervous system, such as a depletion in the number of interconnections between neurons, lowered efficiency of neurotransmitters, increased neural noise (see Kail, 1997) and so forth. The reaction time may thus be not only gauging the speed of transmission, but also giving a general indication of the efficiency and health of the nervous system.

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Older
time
eaction

Younger

R

Complexity

Figure 2.1 Illustration of the age x complexity effect er

Young

Older

Figure 2.2 Illustration of a Brinley Plot, Plotting younger v. older means on same data as Figure 2.1

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Attributing the ageing decline in intellectual skills to a slowing in the speed of neural transmission (and all the related phenomena this implies) is known as the general slowing hypothesis (or, rather confusingly, the speed hypothesis). At a general level, this argument is not greatly disputed: low speed typically equals low test scores.

The debate is principally about the degree to which general slowing alone predicts intellectual performance. As mentioned several times in this and the previous chapter, the age x complexity effect states that as the task gets harder, so older adults become disproportionately more disadvantaged. Underlying this may be an even simpler explanation. The impetus for this came from Cerella (1985; 1990), following earlier research by Brinley (e.g. Brinley, 1965).

If we consider the response times for harder and easier versions of the same task, we find that the times increase as the task complexity increases. Furthermore, the rate of change is bigger for older than younger adults. Thus, a graph plotting task complexity against response time shows that a younger group has a line rising less steeply than that an older group’s (see Figure 2.1). However, what if we plot the response times for older and younger adults on the same tasks against each other? What we will usually find is illustrated in Figure 2.2, and is known as a Brinley plot. What this shows is that the underlying difference between older and younger adults is linear (note that real data rarely do not show a perfect straight line, but allowing for experimental error, a straight line is the best description of the results). For those not mathematically minded, what this means is that the apparent disproportionate difference between older and younger people illustrated in Figure 2.1 is illusory; older adults appear to be disproportionately disadvantaged the more complex the task, but in fact they are not – the real underlying difference remains the same size. This means that complex formulae used to predict changing age differences across different levels of complexity (see Rabbitt, 1996) can be jettisoned; instead, all age differences can be expressed by a simple formula: find the mean reaction time of a younger adult on a task, multiply it by a constant, and that will be the mean reaction time for older people on the same task.

Because of the beguiling simplicity of this theory, the general slowing hypothesis has understandably attracted a lot of attention in the past few years. It has been established that the phenomenon is widespread: across a wide variety of tasks, where average older and younger response speeds can be compared, a linear relationship has been found (e.g. Cerella, 1990; Lindenberger et al., 1993; Maylor and Rabbitt, 1994; Sliwinski et al., 1994; Verhaeghen and De Meersman, 1998). Myerson et al. (1992, p.

266) make the important point that, within a particular domain, ‘the term general slowing would appear to capture the fact that the degree of slowing does not appear to

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depend on the nature of the task or the specific cognitive processing components involved’. In other words, slowing must involve something more basic, such as changes at a neural level (Cerella, 1990).

However, there are several important caveats which limit the extent of general slowing’s applicability. For example, it does not stop the old-young speed relationship being influenced by other factors, such as compensatory strategies by older people:

‘Because of the compensatory effects of lifelong knowledge accumulation, for instance, some domains of cognitive functioning may be less affected by slowing than others. Recent evidence showing that slowing is less pronounced in tasks requiring lexical decisions as compared with analogous tasks requiring nonlexical decisions is consistent with this assumption’ (Lindenberger et al., 1993, p. 207).

This indicates that some caution must be taken in reading too much into the shape of the line. It would be unwise to assume too much about ageing change on the basis of one type of task. In addition, there are some questions about the statistical and mathematical validity of the technique. For example, Perfect (1994) suggests that similar linear relationships can be generated using essentially random data.

Again, Rabbitt (1996) notes that when data increase in variability with task complexity, a linear relationship can still be obtained. This is a mathematically difficult argument, but it essentially means that a considerable amount of the young-old difference may be due to more than just a simple slowing process, but the Brinley plot is masking this. Sliwinski and Hall (1998) observe that in many cases the statistical method used to demonstrate Brinley plots (the ordinary least squares multiple regression, or OLS) is too simplistic and that a hierarchical linear model (HLM) is more appropriate.

When the two techniques are compared on the same sets of data, the OLS produces Brinley plots, whilst HLM identifies rather greater variability. From an empirical rather than a statistical viewpoint, an assortment of disparate findings have indicated that general slowing may not be as strong a predictor as was first assumed (see Bashore et al., 1997 for a review). For example, Sliwinski (1997) reports that cognitive slowing did not seem to be a good predictor of counting speed in tasks of different levels of complexity. Instead, different counting tasks seemed to be mediated by different mechanisms. Again, Shimamura et al. (1995) demonstrated that decline in skills may be offset by use of what is in effect compensation in some individuals. Furthermore, the use of reaction times as an index of mental processing has also been criticised, on the grounds that it is essentially a simplification of what are probably a series of complex and very rapid mental processes, and may thus overlook important subprocesses (Bashore, Ridderinkhof and van der Molen, 1997). In other words, the

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reaction time may be like a camera set at too slow a shutter speed for taking a picture of a particular fast event, such as the finish of a race. The picture which emerges may give a general outline, but there is too much blur to see what is really going on.

Bashore and colleagues argue that EEG measures (see Chapter 1) of brain activity during mental activity may be a more fruitful way forward.

Thus, like many theories in Psychology, the general slowing hypothesis provides a good general description, but is relatively weak on details. Before leaving this topic, one further caveat should be raised. Because reaction times are such a ‘basic’ measure, there is a tendency to assume that they are measuring an inevitable, genetically-ordained change. In fact, whatever the validity of the general slowing hypothesis, changing reaction times are not necessarily predestined to decline. Although the most parsimonious explanation is that declining processing speed results from the physical decline of nervous tissue in tandem with other physical ageing changes, decline may also in part be due to lack of appropriate practice. For example, Goldstein et al. (1997) demonstrated that older people who were given practice on video games improved their reaction times. Again, reaction times are strongly linked to level of health – the greater the number of serious illnesses a person has experienced, the greater the decline in their speed of response (Houx and Jolles, 1993). The same report also found significant effects of level of education. This implies that at least a proportion of the decline in speed may be due to probabilistic ageing (e.g. older people tend to have fewer activities which stretch their reactions, and they tend to have more illnesses) rather than ageing per se.

Given the above arguments about their utility and even allowing for counter-arguments, it is perhaps surprising to find that reaction times seem at first to be fairly weak predictors of ageing performance. Although they are statistically significantly linked to changing intellectual skills, Salthouse (1985) found an average correlation of 0.28 between age and simple reaction times and 0.43 between age and choice reaction times. For those unfamiliar with statistics, this means that ageing can only account for about 8 per cent of the variability in simple reaction times and about 19 per cent in choice reaction times. At first sight, this seems to indicate that the interest in reaction times is unmerited given that they have a relatively peripheral role to play. However, this would be an inaccurate conclusion. Salthouse has provided an ingenious, if mathematically complex rejoinder, which demonstrates that changes in intellectual skills are mediated by the decline in processing speeds (Salthouse, 1985; 1991b; 1992b). In a similar manner, the chains connecting the carriages of a railway train are relatively unimportant in comparison with the power of the engine, but try

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pulling a train without the chains. For further consideration of this issue, see Salthouse (1992b).

The related issue of semantic facilitation, which uses the reaction time technique, is dealt with in the Word Recognition section in Chapter 4.

Thus, reaction times, an expression of speed of neural processing, slow in later life, and this has an influence on the decline in g. The magnitude of this difference can be influenced by practice and by the complexity of the task involved. At one level, this can be described as the age x complexity effect, at another by the general slowing hypothesis. Evidence for either theory is currently equivocal, and whether one wishes to see disproportionate slowing or a constant lag largely depends upon how one chooses to interpret the data. However, to place matters in perspective, it should be noted that reaction times, whilst important, are not the sole arbiter of intellectual change, in spite of some of the more enthusiastic claims by their supporters.

Other physical correlates with intellectual skills

The relationship between reaction time and intellectual performance is a complex one, but nonetheless a relationship exists. It is reasonable to assume that the measure of reaction times is gauging the relationship between the physical state of the body and particularly the brain and the workings of the mind. Indeed, not only the research on reaction times, but also studies of the effects of physical and exercise and health noted above, point to a good correlation between physical status and intellectual functioning. Not surprisingly, therefore, researchers have examined the relationship between physical status and intelligence in older adults. Some of this is relatively piecemeal. A large assortment of researchers have noted that healthy older people tend to have a higher level of cognitive skills. However, without further controls, this is a fairly meaningless statement. For example, people who have good intellectual skills might be more likely to look after themselves and take regular exercise. Therefore, finding a relationship between health and intelligence need not be exactly revolutionary. However, some researchers have been more specific in their activities and some examples of their work will now be assessed.

The first topic concerns the unsurprising relationship between the status of the brain and intellectual functioning. As noted in Chapter 1, the brain loses volume with age (see also Coffey et al., 1999). The same phenomenon has been observed for many subsections of the brain, such as the hippocampus, parahippocampal region and the amygdala (e.g. Jack et al., 1997; Kaye et al., 1997). Given such findings, one might reasonably expect these changes to have psychological correlates. In recent years,

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considerable interest has focussed on the role of ageing changes in the frontal lobes (see Chapter 1) and their effects on intellectual functioning (see Rabbitt, 1997, for an overview). It is known that the frontal lobes are relatively prone to age-related physical decline, and it is also well established that the frontal lobes are heavily involved in many forms of complex thought processes, particularly those involving planning sequences or remembering the order in which events occurred. Evidence that older people show a decline at skills known to involve the frontal lobes is considerable (e.g. Chao and Knight, 1997; Isingrini and Vazou, 1997). Some commentators have argued that the age change in intellectual skills is principally the result of changes in the frontal lobes. For example, Duncan et al. (1996, p. 257) have argued that g may in fact be ‘largely a reflection of the control functions of the frontal lobe’. However, other research has qualified or even contradicted this argument. For example, where

‘frontal lobe’ deficits are reported, not all of the frontal lobe may be involved. Phillips and Della Sala (1998) persuasively argue that many of the supposed ‘frontal’

changes are in fact confined to one region of the frontal lobes (the dorsolateral prefrontal cortex), rather than the whole of the frontal area. Again, it might be intuitively expected that if frontal lobe decline was a major feature of the intellect in later life, then older people would perform in a manner qualitatively similar to patients with damage to the frontal lobes, but at least in some circumstances, this is not the case (Phillips, 1999). Tangential to this, Robbins et al. (1998) found that frontal lobe functions were certainly an important predictor of cognitive skills in later life, but they were not the sole factor, a finding echoed by Whelihan et al. (1997). . Again, Foster et al. (1997) note that many executive/planning functions are not the sole preserve of the frontal lobes, but may be shared between several brain areas. Parkin and Java (1999) demonstrated that a considerable degree of the difference supposedly due to frontal lobe deficits was removed if the scores on a digit-symbol substitution test and a fluid intelligence test (the AH4) were taken into account. Removing the influence of scores on crystallised tests had relatively little effect. In other words, much of the frontal lobe deficit may be a manifestation of a general change in fluid intelligence-related skills. This may apply not just to the frontal lobes but to many supposedly ‘localised’ effects. Salthouse, Fristoe and Rhee (1996) studied age changes in skills associated with the frontal, parietal and temporal lobes, and found that an average of ‘58 per cent of the age-related variance in a given variable was shared with that in other variables’ (p. 272). In other words, although different areas of the brain may each contribute something unique to the pattern of age-related decline, a great deal of what they do is in tandem with other ageing changes.

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These findings must be put in perspective. Arguing that frontal lobes do not have the overwhelming influence which some commentators supposed does not deny the existence of frontal lobe problems. To make an analogy, a naturally clumsy man might break his leg. Seeing him struggling to get around on crutches may be ultimately part of the manifestation of his clumsiness, but that does not mean that the specific problems associated with a broken leg have gone away. In other words, whether frontal lobe problems are a cause of age-related decline, an effect, or a bit of both, does not stop them being a significant factor in considerations of ageing decline in intellectual skills. Likewise, it would be breathtakingly naive to assume that changes in brain structure might have no effect on psychological functioning (see Woodruff-Pak, 1997, for a comprehensive introduction to neuropsychology and ageing). However, it is also important to remember the caveat raised above that an apparently ‘basic’ decline in neural functioning is not necessarily uncontrollable. For example, Coffey et al. (1999) observed that brain volume was relatively preserved in people with higher levels of formal education. Again, Kramer et al. (1999) demonstrated that aerobic exercise (though not simple stretching and toning) had a significant improving effect on performance of frontal lobe-related tasks.

Another aspect of physical decline which has been strongly associated with intellectual change is the worsening sensory system. As was noted in Chapter 1, there are logical grounds for assuming that as sight, hearing etc. decline, the information the brain has about the surrounding world will be compromised, and this will have an effect on mental processes. Furthermore, a decline in the senses may be a general gauge of the body’s and hence the brain’s physical fitness. This may be of greater relevance than might first be supposed. In recent years, considerable attention has been paid to empirical evidence of a strong correlation between measures of sensory functioning and intelligence. For example, Lindenberger and Baltes (1997) found that under certain conditions, measures of sensory and sensorimotor skills predicted the majority (59 per cent) of variance in intelligence test scores in older adults. This relationship appears to grow stronger through adulthood. Baltes and Lindenberger (1997) found that the variability in intelligence test scores explained by the status of sensory functioning (as measured by auditory and visual acuity) rose from 11 per cent in a group of adults aged under 70, to 31 per cent in adults aged 70–103. In both age groups, sensory functioning was correlated with fluid intelligence. The authors conclude that the status of the senses is a good index of biological ageing, and that this may be the main factor influencing intellectual skills in later life. The influence of good sensory functioning may stretch further. For example, Marsiske, Klumb and Baltes (1997) found that older people’s perceived level of basic competence and the degree to

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which they participated in social activities were both correlated with their sensory acuity (and particularly their vision). There is little dispute that these are robust findings, and that the status of the senses is a good gauge of physical and mental functioning. Once again though, caution must be exercised before one interprets this phenomenon as genetically preordained. For example, older people with high IQs are likely to be better at looking after their health (e.g. going for regular eye tests) and may have had occupations which did not expose their senses to potential damage (e.g. working in a quiet office rather than on the factory floor). For example (with tongue only slightly in cheek), good senses and high IQ may be part and parcel of a more general factor of good self-preservation skills. However, whatever the cause, Lindenberger and colleagues have provided a very useful gauge of ageing intellectual change.

Intelligence level and its relationship with specific intellectual skills A great many intellectual skills (particularly those reliant on fluid intelligence) decline in later life (Horn, 1982) by becoming slower and/or less accurate. For example, the following have all shown an age-related decline: memory for word lists, identifying briefly presented visual images (Walsh et al., 1979); pattern recognition (Walsh, 1982); finding solutions to anagrams (Witte and Freund, 1995); everyday problem solving (Diehl, Willis and Schaie, 1995; Sorce, 1995); and speed of planning a driving route (Walker et al., 1997). About the only skills found to be unrelated to ageing are arguably rather less cerebral, such as finding solutions to social problems (e.g. Heidrich and Denney, 1994) and time taken to give up trying to solve an insoluble puzzle (Stuart-Hamilton and McDonald, 1998). The cause of the age-related decline is usually easy to find. In a review of the literature, one author concluded that:

‘Such changes in intellectual competence as may occur with ageing are much better picked up by a simple, brief, timed test of general intelligence, than by any single specific cognitive measure we have yet explored.’ (Rabbitt, 1984, p. 113).

Rabbitt is probably deliberately overstating the case, but certainly most intellectual changes in later life are strongly tied to, if not uniquely explained by, the decline in general intelligence. This raises a serious problem for some researchers. Suppose that an experiment discovers that older adults are significantly worse at mental arithmetic and suppose also that this is explained by a general fall in intelligence. If one is interested in discovering what makes older and younger people different from each other, then this finding is dull, because it tells one nothing new about ageing – the

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drop in arithmetic skills has been shown to be nothing more than yet another manifestation of a general decline in intelligence which is already thoroughly documented. It is about as earth-shattering as the finding that elephants have big toenails.

This is not to say that the experiment is of no value at all. For example, the researchers may be able, from their results, to construct a detailed model of how ageing affects mental arithmetic (i.e. explain why the changes take place). If the findings are not used for model-building, then the study might still be of value from a practical viewpoint. Thus, the study might lead one to exhort older adults to use a calculator when they go shopping. Throughout this book there are examples of tests of intellectual ability, many of which demonstrate that the decline in a skill is attributable to general intellectual decline, and their value must be weighed against the above considerations. It is the instances where the decline in a skill is not in tandem with the general pattern of changes which are often more interesting.

There are a variety of ways in which the effect of general intelligence on performance can be assessed. The two simplest are matching and partial correlation.

The former involves comparing groups of people who are known to have the same level of ability at a certain skill. Thus, any difference between the groups cannot be due to that skill. For example, suppose younger and older people with the same intelligence test scores are compared on a task, and an age difference is found. This cannot be due to differences in intelligence. Matching is a useful technique, but it is often difficult to get good matches between people, especially in different age groups. In such circumstances, partial correlation may provide a solution. This is a statistical technique which is quite complex to perform, but relatively easy to explain. It assesses whether the relationship between two variables is due to the common influence of a third. To take a standard example. Suppose some strange passion drove a researcher to measure schoolchildren’s feet sizes and to compare these with their scores on a maths test. It is highly probable that there would be a good positive correlation between the two measures – that is, on average, the bigger the foot size, the bigger the test score. There is obviously not a causal connection between the two measures, so why the correlation? The answer lies in a third factor – age. Older children have bigger feet and also will perform better on maths tests. Therefore, the feet-maths correlation is the coincidental effect of the influence of a third variable (i.e. age). This can be demonstrated mathematically using the partial correlation technique. The children’s feet sizes, test scores, and ages are fed into the equation, and the coincidental effect of age is removed mathematically – that is, age is said to be partialled out. If, after this has been done, there is no longer a significant correlation between feet size and test scores, then it is valid to assume that the effect was at-

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tributable to the coincidental effect of age. The partial correlation technique is an important one in gerontology, because it enables researchers, amongst other things, to test if an ageing decline on an intellectual skill is solely due to the coincidental effect of a general fall in g. Further information about the mathematical rationale behind the method can be found in any general statistical textbook.

Another important caveat concerns the cohort effect, which can manifest itself in several forms, and can skew results either to exaggerate or diminish ageing effects.

For example, there is evidence that some cognitive skills are well preserved in later life because, although some aspects of performance (such as memory) decline, the older person’s greater experience can compensate for this, as was seen in Charness’s studies of bridge and chess players and the training studies in intellectual skills cited above.

Attentional deficits in ageing

Attention is the ability to concentrate on and/or remember items, despite distracting stimuli (which may have to be simultaneously mentally processed). Attention manifests itself in several forms. The ability simply to concentrate on the task at hand without being distracted is known as sustained attention. A typical test of this might be to require a participant to respond every time a particular letter appears in a continuous stream of letters presented on a computer screen. Ability on sustained attention tasks is known to be quite well preserved in later life: there is some decline, but it is not appreciable (Salthouse, 1982). It is also notable that older adults prefer visual attention tasks to occupy a small rather than wide visual field (Kosslyn, Brown and Dror, 1999).

Selective attention refers to the ability to concentrate on the task at hand whilst there are other distracting stimuli present. A popular method of testing this is the visual search task. Participants are shown a display of (for example) letters, and are told to find a particular letter. Rabbitt (1979) showed that older people are much slower at this task. Furthermore, the older people did not take advantage of a feature of the experiment: namely, that the target appeared more often in some positions than others. Older people’s responses were the same speed whether the target was in an often- or rarely-used position. Younger participants, on the other hand, were faster for the frequently-used positions. This was not because older people were unaware of the phenomenon: at the debriefing after the test session, they could accurately identify where the target was most likely to appear. Hence, they could accrue the information but not act upon it. Furthermore, repeated practice did not seem to

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improve their performance (Rabbitt, 1982). Other researchers, however, have failed to replicate Rabbitt’s findings. For example, Gilmore, Tobias and Royer (1985) found that older people can use information conveyed by a visual array, and Nissen and Corkin (1985) showed that, in their experiment, older adults responded relatively faster to a target appearing repeatedly in the same position. Other studies have shown that the presence or absence of an effect depends upon relatively peripheral features of the experimental design, such as the size, shape and brightness of the stimuli (Albert, 1988). Where age differences are found in visual search tasks, Walsh (1982) has demonstrated statistically that the slowing and loss of accuracy in older people cannot be solely due to a general slowing in neural transmission.

In another test of selective attention, McDowd and Filion (1992) gave participants the task of listening to a tape of a radio play, whilst a number of tones were played.

In the key experimental condition, participants were told to ignore the tones and concentrate on the play. The degree to which participants succeeded in this task was measured by testing skin conductance and heart rate – if the tones were being ignored, then neither measure should show a change when they were played. After the first few tones were played, younger participants successfully ignored them, but older people could not, and their responses remained at the same high level throughout the experiment. Again, Friedman, Hamberger and Ritter, (1993) found that brain potentials (electrical activity produced by the brain) were far more pronounced in older than in younger participants when presented with a repeated stimulus. Comparable results on EEG patterns have been reported by Amenedo and Fernando (1999). These findings reflect the studies of Bergman et al. (1976) and Dubno et al. (1984), which found that older people are disproportionately disadvantaged when trying to follow auditory messages played against noisy backgrounds. This is evidence of a more serious attentional problem than has been found in many visual attention tasks. However, Murphy, McDowd and Wilcox (1999) demonstrated that many aural attention experiments failed to allow adequately for hearing loss in the older participants. When the sound volume of the stimuli was adjusted to allow for this, the researchers found identical patterns of response for older and younger adults. At the time of writing, this is a recent finding, and it will be interesting to see how this affects future empirical work in this area. However, it implies that many of the age differences in auditory attention studies may at least be inflated, if not created, by a cohort effect.

Divided attention refers to the ability to attend simultaneously to and process more than one source of information. Many working memory tasks (see Chapter 3) fall into this category. The best-known method of assessing divided attention is

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probably the dichotic listening task. Using stereo headphones, the participant is presented with a different message in either ear. Typically, the participant must report what he or she heard in either ear separately. Many researchers have shown that older people are bad at this task (e.g. Horn, 1982; Salthouse, 1985). More generally, researchers have found that there is an ageing deficit on tasks requiring the sharing of attention between two or more sources (e.g. Lajoie et al., 1996; Vaneste and Pouthas, 1999). Various theories have been advanced to explain this phenomenon. Salthouse (1985) argues that the effect is yet another manifestation of the age x complexity effect. This is for two main reasons. First, because on simpler attention tasks (e.g. sustained attention), the age difference is less pronounced. Second, if the information load is lessened, then the age difference is also diminished (Albert, 1988). Why the age x complexity effect should manifest itself is harder to explain.

For example, it is resistant to being comfortably explained as another manifestation of general slowing (Brink and McDowd, 1999; Lowe and Rabbitt, 1997; Wickens et al., 1987). Salthouse (1985) showed that older people are as able as younger people at shifting and allocating attention in a divided attention task, and thus it can be concluded that both age groups are using the same working methods. The most parsimonious explanation is that older people suffer from a general loss of processing resources: in other words, through general neural decline, they no longer have the ‘mental capacity’ to attend to as much at one time as they could in their youth.

This explanation seems to fit the available evidence. Salthouse (1985; especially Chapter 7) provides more detail and a lengthy technical argument supporting this.

At a neurological level, the decline of the frontal lobes (strongly linked with attention) may also play a role (see Lowe and Rabbitt, 1997; Woodruff-Pak, 1997) and more generally a failure within the brain to screen neural signals effectively from each other (see Woodruff-Pak, 1997, for a review).

Conceptual organisation

As reaction times measure the mind’s immediate reactions to stimuli, so conceptual organisation describes the ability to treat items at an abstract level, in order to uncover basic rules and principles. For example, a man, a gerbil and an elephant are visually dissimilar, but at an abstract level they are all examples of mammals. Again, a proverb such as ‘people in glass houses shouldn’t throw stones’ is of value only to greenhouse owners unless it is treated at a symbolic level. Researchers have shown that, in many instances, older people have difficulty in moving from the concrete to the abstract. Perhaps most surprising is the finding of Albert, Duffy and Naeser (1987) that older people were worse at interpreting the meaning of proverbs. This

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applied whether participants were left to provide their own answers unaided, or were given a multiple choice test. This is at first sight a contradictory finding, because one would suppose that proverb interpretation is part and parcel of wisdom and crystallised intelligence, and thus age-invariant. It is possible that Albert et al.’s results are attributable to a cohort effect. However, as has been remarked above, it is also possible that crystallised intelligence is less ‘ageing proof’ than most commentators believe.

Another test of conceptual abilities is the ‘twenty questions’ type of task. This is a version of the parlour game in which the participant is told that the experimenter is thinking of an object, and by a series of questions, to which the experimenter can only answer ‘yes’ or ‘no’, the participant tries to elicit the name of the object. Clearly, the optimal strategy is to narrow down the field by asking questions which progressively constrict the choice of alternatives (e.g. ‘is it an animal?’, ‘is it a mammal?’, ‘is it a household pet?’). This is called a constraint seeking strategy, because the choice of possibilities is increasingly constrained by each question. Eventually, when the list is down to a small number, it is best to switch to a hypothesis scanning question, where a specific item is named (e.g. ‘is it a dog?’). If a hypothesis scanning question is asked when the list is still large, then this is a foolish strategy, because the chances of hitting on the right name are too remote (e.g. asking ‘is it a dog?’ having only established that the animal is a mammal). Denney and Denney (1974) found that older people are far less efficient at the twenty questions task. They had to ask more questions before getting the right answer, largely because they asked fewer constraint seeking questions. Older people are disadvantaged in an analogous fashion when they are given a range of items, and asked to divide them into groups. Clearly a good strategy would involve the grouping of items into superordinate categories (e.g. ‘animals’, ‘items of furniture’). However, older participants tend to produce more groupings where the linkage between items is illogical to an observer (Denney and Denney, 1973). It might be argued that the decline in categorisation skills is due to an artefact of declining memory (i.e. older adults cannot simultaneously keep in mind everything they need to sort through). However, varying the memory load by varying the number of items to be categorised has no appreciable effects on performance (see Rebok, 1987). Neither can differences in education level provide a total explanation (Cicirelli, 1976; Laurence and Arrowood, 1982). Nor again can a cohort difference in knowledge of how to deal with this sort of task, since even after being shown the best strategy, older adults failed to use it as extensively as younger controls (Hybertson et al., 1982).

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Another explanation (and perhaps the most parsimonious) is that declines in classification skills are tied to a general decline in g. Laurence and Arrowood (1982) compared the performance of (Toronto) university students, elderly alumni from the same university, and hospitalised older adults, on a classification task. No significant difference was found between the alumni and students, but both groups were significantly superior to the hospitalised group. Although no IQ data are provided, it is reasonable to assume that the alumni’s intelligence levels were ‘well-preserved’ (this would accord with studies of similar groups). Hence, classification skills probably only decline when intelligence begins to fall, as in the case of the hospitalised older adults. Laurence and Arrowood also noted that the error made most often (43 per cent) by the hospitalised group was sentential grouping – items were linked together because they fitted into a sentence (e.g. ‘the bunny ate the carrot’). This was rarely if ever done by the other two groups, who made errors, but these were usually due to relatively minor slips of logic. Thus, deleterious ageing can result in quantitative and qualitative changes in classification skills. Furthermore, Arenberg (1982), in a longitudinal study, showed that younger participants’ performance on a conceptual formation task improved on subsequent test sessions, whilst the older participants got worse.

However, it may be observed that when people make ‘errors’ in a classification task, they are only ‘wrong’ because their classifications do not conform with what the experimenter wanted. Grouping a carrot with a rabbit is perfectly sensible; although, in a wider scheme of things, it is not the most elegant solution, it is perhaps more fun (that participants might seek amusing solutions does not seem to occur to many experimenters). Denney (1974) argues that older people make grouping mistakes, not because of any ‘decline’ but because they forget the accepted ‘correct’ way of grouping things as defined by educational practice, and instead adopt an arguably more

‘natural’ method of grouping. This may be coincidentally related to education level and intelligence, because higher education and intelligence people tend to enter professions and have leisure activities more demanding of formal grouping practices, and thus maintain these methods longer than other people.

If a ‘failure’ of grouping does occur, then the change need not be as bad as it may first appear. For example, the decline observed by Arenberg was not appreciable until the participants were in their seventies. More encouragingly, Labouvie-Vief and Gonda (1976) found that older people can under some circumstances improve their classificatory skills with practice. Also, older adults perform better if the tasks have an obvious practical slant rather than being purely abstract. For example, Arenberg found that older people were better at working on problems where items of food

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were grouped to produce ‘safe’ and ‘poisonous’ combinations than when given structurally identical problems of set formation using abstract shapes.

Critics might argue that the studies reported above are relatively ‘gentle’ classification tasks. Where there is added difficulty (e.g. being required to transfer between categorising items in one way to categorising them in another), then age differences become more pronounced, and there is good evidence that this is attributable to differences in frontal lobe functioning (e.g. Kramer et al. , 1995; Levine, Stuss and Milberg, 1995). However, these more difficult tasks may also be more demanding of other cognitive processes, and it is doubtful if they are testing the same genre to skill.

Creativity in later life

Running in tandem with general intelligence is creativity. Researchers are divided on how best to describe the skill, but most would agree that for an act to be creative, it must be novel, and it must be appropriate to the situation. The best way to demonstrate what is meant by this is to consider a typical creativity test. The participant is presented with a house brick and is asked to think of as many uses for it as possible. There are two types of responses which are classified as being

‘uncreative’. The first is appropriate but conventional (e.g. ‘use it in building a house’). The second is novel but inappropriate (e.g. ‘use it to cure insomnia by knocking yourself out with it’). A creative answer would be something like ‘scrape the surface of the brick to make rouge’ (i.e. something both novel and feasible).

People who produce a lot of creative answers are said to be good at divergent thinking (i.e. given a simple situation they can produce answers which diverge from mainstream thought). Studies have found that older people are poorer at divergent thinking tasks. It might be argued that this is because the older also have depleted intellectual skills in general. However, the age difference persists even when older and younger participants are matched for intelligence and education level (Alpaugh and Birren, 1977; McCrae, Arneberg and Costa, 1987). Among individuals who have always been very creative, this difference may be lessened or even not be present (e.g. Crosson and Robertson-Tchabo, 1983). Again, Sasser-Coen (1993) has argued that divergent thinking becomes generally less important in the creative process as people grow older, with greater emphasis placed on items generated from personal experience. An important caveat to the findings of the above studies is raised by Simonton (1990) and separately by Hendricks (1999), which is simply that the applicability of divergent thinking tests, along with other psychometric measures, is

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debatable, and that they may not be reliable indicators of ‘real life’ creative abilities in all cases.

Another way to consider creativity is the biographical approach. By this method, the lives of acknowledged leaders in fields of activity where originality of thought is highly prized are examined, to see what made or makes them ‘better’ than others.

Some generalisations can be gleaned from such studies. Artists and musicians tend to display their talents early in life (e.g. Mozart), whilst scientists are usually in their twenties before they show signs of outstanding ability. In addition, scientists are often competent, but not outstanding students, until the area of specialisation in which they will become pre-eminent grips their imagination (Hudson, 1987). Charles Dar-win was a classic example of this. Thereafter, most eminent persons make their major contributions to their field before the onset of old age. Most have a peak of creative output before they are 40. This applies to disciplines as diverse as mathematics, chemistry and musical composition. It is important to note that ‘great’ and ‘routine’

pieces of work tend to be produced in tandem. In other words, in a prolific period, a creative person will produce the same ratio of good to indifferent work as he or she will during relatively unproductive periods – in other words, the quality ratio stays fairly constant (Simonton, 1990). Creativity has for most people died away by their sixties (see Rebok, 1987). However, this is not universally true, and Butler (1967) has made a spirited counterattack to this view, citing numerous masterpieces produced late in their creators’ lives. Titian, for example, continued to paint into his nineties, and most critics agree that his later work far surpasses his earlier output. However, Butler cites notable exceptions. For the majority of creative people, ageing is associated with a decline.

It can be argued that the sensory and physical declines of ageing will affect creative people especially badly, because above all others they need a precise, accurate, and untiring view of the world (Rebok, 1987). Undoubtedly in some creative fields, where physical fitness is de rigeur, this is true. Opera singers and ballet dancers are never at their peak in old age (but equally, there are few ballet dancers over 35 who still perform on the stage). However, for the majority of creative persons, another explanation must be sought, since there is a long list of innovative people who have succeeded in spite of, or even because of, physical incapacity. For example, it is well known that Beethoven was deaf in his later years, and this fact may account for some of the innovations in his later works, when he had to rely on an imagined world of sound. Mahler suffered from a crippling heart condition, which probably contributed to the angst-ridden nature of his later work (indeed, the irregular rhythm of his heart beat is incorporated into the opening of his ninth symphony). Stephen

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Hawking, perhaps the most famous of contemporary theoretical physicists, is nearly completely paralysed by motor neuron disease, a condition, which by his own admission, has encouraged him to think about his work. In short, there is plenty of evidence that creativity need not be affected by physical declines far more severe than those experienced in normal ageing. Similarly, attribution for the effects of ageing cannot be laid upon a general intellectual decline, for two main reasons. First, because as was seen from Alpaugh and Birren (1977) cited above, age differences in creativity exist even when intelligence levels are matched. Second, intelligence is in any case a poor predictor of creativity (Hudson, 1987). Therefore, another explanation must be sought.

One possibility is that creative people are victims of their own success. Scientists who achieve pre-eminence in their field are likely to find themselves quickly elevated to headships of departments or research groups. Once in this position, much of the running of experiments and ‘hands on’ experience is passed on to research assistants, whilst the head of department finds him- or herself embroiled in an increasing quantity of administrative duties. Thus, the eminent scientist’s reward for success at a particular endeavour may be to have his or her future activities in the field restricted, thus causing a decline in creative output. A different set of values probably applies to people pre-eminent in the arts. First, far more than scientists, artists (of any type) rely for their success on critical and public opinion. Accordingly, the worth of an artist depends upon what is fashionable at the time, and to be considered creative, the artist must be seen as a leading interpreter of the fashion and/or to have been the creator of that fashion. A second consideration is that few artists are able to support themselves if their craft does not pay. Accordingly, if they do not achieve success in early life, they are likely to withdraw from full-time creative activity and seek other employment. It follows from these two premises that the creative person usually becomes noticed for being a skilled exponent of a current fashion at an early stage in his or her career. Obviously, the artist seeks to capitalise on this, and accordingly becomes increasingly identifiable with that fashion. However, opinions change, and almost inevitably the artist becomes a representative of a movement which is now unfashionable. The more successful he or she was, the more strongly he or she is now identified as being unfashionable. In short, successful artists are hoist by their own petard (for a brilliant fictional account of this, see the shamefully under-regarded novel Angel by Taylor, 1957). The only solution for most artists is to move with the fashion. Since this probably involves a radical change of style, their output is likely to suffer. The speed at which these changes occur vary from discipline to discipline.

Anyone keen on pop music will know that a cycle such as the one described occurs

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every three or four years. However, in any field, there are very few artists who produce ‘timeless’ works which rise above the mercurial changes of fashionable opinion.

For example, a quick perusal through a second-hand book shop or a musical dictio-nary will readily reveal how many ‘geniuses’ of literature and music from previous generations are now completely forgotten. Thus, the reasons behind the changes in creative output across the lifespan may be due far more to the lifestyles and job demands of the gifted than to ageing per se. Older people may have ‘lost’ their creativity because they were too good at their job earlier in life.

The above arguments apply to people who are outstanding in their field, but they do not deny a role for creativity in everyday life. In fact, there is considerable evidence that engaging in creative activity (e.g. painting, writing, and so on) is of considerable value to older participants, and is reported as enhancing feelings of well-being and general self-esteem (e.g. Hickson and Housley, 1997).

Piagetian conservation

Papalia (1972) demonstrated that older people are bad at some of the Piagetian conservation tasks (named after their inventor, Piaget). This is a surprising finding, because most seven-year-old children can successfully perform them. The tasks in question test participants’ knowledge that two items of equal volume remain of equal volume even when one of them changes shape. The participant is shown two balls of modelling clay of equal size and shape, and agrees that each is composed of the same amount of clay. The experimenter then rolls one of the balls into a sausage shape, and asks the participant if the two pieces have the same amount of clay in them, to which of course the answer is ‘yes’ (pedants note that one ignores the minuscule amount lost on the hands and table surface during rolling). It is surprising that ageing should cause people to fail what appears to be such a simple task (and indeed, Piaget thought it impossible). The decline is not limited to conservation of matter and may be demonstrated on a surprising range of Piagetian tasks, such as moral reasoning (McDonald and Stuart-Hamilton, 1996), and animism – the erroneous belief that some inanimate objects are alive (McDonald and Stuart-Hamilton, in press).

Certainly, older people who fail Piagetian tasks are not incapable of performing them, since they can be easily retrained to do them correctly (Blackburn and Papalia, 1992). Hooper, Fitzgerald and Papalia (1971) suggest that skills necessary to perform Piagetian tasks may be lost in the reverse of the order in which they were acquired during childhood, and may also be strongly linked with changes in fluid and crystallised intelligence. However, more recent research by McDonald and

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Stuart-Hamilton (e.g. Stuart-Hamilton and McDonald, 1996, 1999) suggests a more complex tale. If older people’s performance on a wide variety of Piagetian tasks is measured, then it is possible to create a ‘Piaget score’ (i.e. the total number of tests correctly performed). This is a better predictor of participants’ ages than their intelligence test scores (Stuart-Hamilton and McDonald, 1996). In turn, the best predictor of Piagetian score is a personality measure called need for cognition (Stuart-Hamilton and McDonald, 1999). This is a measure of the drive a person feels to pursue intellectually-demanding tasks as part of their lifestyle, as opposed to their actual level of intelligence. Overall, this implies that the changes in Piagetian performance may reflect an older person’s level of involvement with intellectual tasks and (for want of a better expression) an ‘intellectual lifestyle’. As a person gets older, they may become less committed to certain intellectual pursuits, and their methods and styles of thinking shift (no value judgement is implied in this, see Chapter 7). Such changes will correlate reasonably well with performance on intelligence test scores, but this is in part coincidental.

To some extent this echoes the argument by Labouvie-Vief (1992), who proposed a concept of postformal thought. This is a stage of intellectual development, which, it is argued, occurs in adulthood, after the stage of formal operations (the final stage of Piaget’s theory of development in which people begin to think in genuinely abstract terms). Formal operations is very systematic and relies on logical processes. However, it can reasonably be argued that people do not spend their lives being logical, and that many important decisions are made by not only cold logic, but also considerations of emotions and other subjective feelings. Accordingly,

‘postformal thought’ refers to this ability to weigh up and balance arguments created by logic and emotion, and is similar in some respects to the discussion of wisdom earlier in this chapter. However, whilst this is a useful operational distinction, it is debatable whether formal and postformal thought are intrinsically different, since arguments created from an emotional source and arguments created from a logical source can be combined logically, without the need for a ‘new’ kind of thinking. A cynic might argue that a further danger is that the theory might be used to excuse some age-related declines in intellectual performance by relabelling failures to perform tasks as examples of alternative strategies. It is also hard to justify a stage of postformal thought when there is evidence that a significant proportion of older adults are jettisoning earlier stages of Piagetian development. More probably, some older adults lose skills because they are no longer important in their lives (see Chapter 7 for further discussion of this point). This raises potentially awkward questions for more general studies of intellectual change in later life. Many studies have as-

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sumed that participants, both younger and older, are using the same set of mental skills, albeit with varying efficiency. However, if a significant proportion of older adults are using different logical systems, then is such a comparison fair or meaningful?

Summary

Older people have traditionally been seen as retaining crystallised skills and increasing their wisdom, whilst showing a decline in fluid intelligence. Research has generally backed this conclusion, but only at a relatively broad level. Inter alia, it should be noted that: (a) some older people preserve their youthful level of fluid intelligence; (b) the size of the difference is in part an artefact of the experimental and analytical methods used; (c) the ‘preservation’ of crystallised intelligence relies on tests not being timed. Where an age change is noted, it can be considerable, being on average nearly two standard deviations below the mean of a younger group.

However, in all of the above cases, the cohort effect exaggerates the effects.

Longitudinal studies lessen age differences, but they are also expensive and (obviously) time consuming to run. There is some evidence that in younger older people, a sudden decline in intellectual abilities is a harbinger of death (though commentators are divided on which intellectual skills need to decline). Various models of ageing change have been proposed, including the disuse theory (that skills decline because they are insufficiently practised) and the general slowing hypothesis (that the changes are due to a slowing in neural conduction). The former has some validity (particularly through the related issue of compensation), but has difficulty in explaining why certain well-practised older people still display a worsening of skills.

The latter theory is backed by some intriguing evidence (particularly Brinley plots), but evidence also suggests that at least some variability in skills is left unexplained.

Declines in more specific intellectual skills, such as attention, conceptual organisation, creativity and Piagetian task performance, have all been well documented. However, in all instances, cohort effects or lifestyle changes may strongly colour the results. Indeed, in general, it would appear difficult if not impossible to decide how much of ageing change is due to cohort effects rather than

‘pure’ ageing.

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Suggested further reading

There are innumerable textbooks on intelligence and intelligence testing. However, the issues they raise are technically very complex, and the writing sometimes reflects this. Some knowledge of psychology and basic maths is often required. This should not deter the interested reader, but he or she has been warned! Perhaps the best (and most readable) summaries of the issues pertaining to ageing are provided by Rebok (1987) and Perlmutter and Hall (1992). More specialised texts by Bergeman (1997) and Woodruff-Pak (1997), with a genetic and neurological emphasis respectively, may also prove useful. Salthouse (1991a;b; 1992a;b) provides a suitably exhaustive (and exhausting!) critical review of the ageing and intelligence literature. A more critical consideration of problems with testing older adults is provided by the present author in Chapter 7 of this book and in another work (Stuart-Hamilton, 1999b). For a discussion of the fluid-crystallised dichotomy, Kausler (1982, pp 584–598) is recommended, as is Rabbitt (1984, 1993). Regarding the declines in more specific skills, Craik and Trehub’s edited collection (see Horn, 1982 reference) is a collection of thoughtful, well-written papers, as is Poon et al. (1989) (see reference for Perlmutter and Monty, 1989). Butler (1967) gives a detailed consideration of the creative arts in later life, whilst Simonton (1990) provides an intelligent and interesting summary of the recent literature on the subject. For readers wishing to gain an overview of changes in intellectual skills across the whole lifespan, Turner and Helms (1995) is warmly recommended. A shorter overview is provided by Stuart-Hamilton (1999a).

chapter 3

Ageing and Memory

Introduction

The study of the psychology of memory has generated a large number of concepts and technical terms, and a brief survey of at least some of these is necessary before an examination of the effects of ageing on memory skills can begin. A belief held by many lay people is that memory is a homogeneous skill: that is, everything is memorised in the same way. This is erroneous, simply because physiological research has demonstrated that different types of memories (e.g. for word, pictures, physical skills) are stored in anatomically different sections of the brain (see Chapter 1).

Furthermore, psychologists have found that these memory systems also behave in different ways. Accordingly, when researchers talk, for example, of ‘verbal’ or ‘visual’

memories, they can be confident that they are discussing anatomically and functionally distinct systems.

One of the simplest ways of categorising memories is by the length of time over which they are retained, and this usually means a division into short term memory (STM) and long term memory (LTM). Short term memory is the temporary storage of events and items perceived in the very immediate past: that is, no more than a few minutes ago, and usually a much shorter period (i.e. the last few seconds). The classical test of short term memory requires the experimenter to read out a list of letters, numbers or words, and get the participant to repeat it back. The longest length of list of these to-be-remembered (TBR) items which can be repeated back reliably is called the participant’s span. Spans vary according to the nature of the TBR items and thus, there is usually a prefix denoting the materials used in the test. Hence, digit span denotes memory for numbers, word span memory for word lists, and so forth.

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One of the problems with the classical span experiment is that it is not very realistic: people simply do not spend very much of their time learning arbitrary lists. Another point is that short term memory is impermanent: unless an especial effort is made, the memory fades within a brief time. A popular explanation of why there is a short term store, and how it might function, is provided by Baddeley and Hitch’s (1974) working memory model. Working memory is defined as:

‘the temporary storage of information that is necessary for such activities as learning, reasoning, and comprehension’ (Baddeley, 1986).

Thus, typical tasks involving working memory:

‘are those in which the person must hold a small amount of material in mind for a short time while simultaneously carrying out further cognitive operations, either on the material held or on other incoming materials.’ (Morris, Graik and Gick, 1990, p.

67).

This is a form of short-term memory which most people can intuitively appreciate that there is a need for. For example, in listening to speech, it is necessary to keep in mind what a person has just said in order to make sense of what is currently being said. Another example of working memory in action is mental arithmetic. All the figures of the sum have to be retained (in the right order) while the arithmetic transformation is performed on them. Note that in both these instances something has to be remembered whilst another mental operation takes place.

Full details of how the working memory model is presumed to operate are still far from finalised. However, in its basic form the system is said to be controlled by the central executive. This is in part a memory store (though with a limited capacity) and in part a controller of several slave systems. These have larger memory capacities than the central executive, and each specialises in only one type of memory. Thus, there are separate systems for verbal material, pictures, and spatial position. The verbal material system is called the phonological loop (in some older texts it is called the articulatory loop). This deals with words in the broadest possible sense, and thus not only memorises letters and words, but also numbers. The central executive controls the depositing and retrieval of memories to and from the slave systems.

When concurrent processing is required (i.e. maintaining a memory and doing another attention-demanding task at the same time) the central executive helps to co-ordinate these. It is important to note that if there are too many TBR items to fit in the slave systems (i.e. the slave systems by themselves cannot remember everything

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sent to them), then some or all of the items can be transferred to long term memory, which thus acts as a backup.

Memory traces quickly fade from short-term memory for the simple reason that the vast majority of information taken in is only of value at the time, and afterwards is highly redundant. To return to the example given above, remembering the numbers in a mental arithmetic problem is necessary at the time, but to keep remembering them afterwards would be both an irritation and a waste of memory space. However, there is obviously some information which does need to be remembered more permanently, and this is the role of long-term memory.

Long-term memory seeks to be a permanent store of information. Whether it has a maximum capacity, and how much information is lost from it are unanswerable questions. However, it is certainly the case that for people not suffering from amnesia,

‘essential’ and ‘everyday’ information is never lost. For example, people do not forget their native language, their names, the name of the capital of France, or toilet training.

In all probability, this is because such information is either very important to them and/or it is so frequently rehearsed (i.e. the memory is recalled and thus ‘practised’) that they form strong, unshakeable memory traces. Some information is lost from long-term memory, however (e.g. old addresses, telephone numbers, etc., tend to be forgotten when friends move). These lost memories tend to be either information which is now irrelevant and has been superseded, or is unimportant, so it is infrequently rehearsed. The classical test of long-term memory is the same as the short-term memory ‘span’ procedure, except that the participant is required to hold the TBR items in memory for a longer time (typically, anything from 30 minutes up to several days). If the reader is wondering why participants do not forget the TBR
items as with the short-term memory experiment, the simple answer is that the participants are encouraged to rehearse them.

Another method of categorising memory is into episodic and semantic memories (Tulving, 1972). Episodic memories are of personal experiences (a deceptively similar concept is autobiographical memory, referring to memory for events specific to one’s personal life). Semantic memory is for items independent of personal experiences and is a store of facts, such as general knowledge, or academic learning.

A further system divides memory into explicit and implicit memories (Graf and Schachter, 1985). This refers to the distinction between a memory which is consciously sought (e.g. trying to recall the date of the Battle of Waterloo) and one which can be gleaned from memory, but which has not been deliberately stored. For example, one method of testing implicit memory is to expose a participant to a list of words in the guise of a psychological task (e.g. grading words for the level of visual

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images they provoke). At a later time, the participant is given a word completion task, in which a word must be provided, having been given its first letter or letters (e.g. ‘complete FOR_ _ _’). The participant is more likely to provide a word he or she has encountered in the previous list (e.g. ‘FOREST’ rather than ‘FORGET’), even though he or she may be unaware that these memories are being drawn upon. In other instances, implicit memory may refer to inferences which may be drawn from memories, even though the inferences themselves have not been explicitly stored.

For example, people can readily answer the question ‘does Elton John have two legs?’ by extrapolating the information from the memory that Elton John is a pop singer, pop singers are humans, and humans are bipedal. In short, people can have a

‘memory’ that Sir Elton has two legs, even though it is not stored as an explicit statement of fact.

Tangential to the above domains of memory are the skills of planning and overseeing. One of the commonest uses of memory is to remember to do something in the future, or prospective memory. Conceptually related to this is metamemory, which is knowledge about one’s own memory – what its capacity is, how best to remember things, and so forth.

Memory systems can also be considered in terms of how they work: for example, how memories are created for storage (encoding) and how they are retrieved. There is a considerable debate within psychology as to whether memories are lost through inefficient coding or inefficient retrieval. The inefficient coding hypothesis can be likened to a library where an incompetent librarian puts books on the wrong shelves, so that when a search is made for a book, it cannot be found in its rightful place. Similarly, memories that are inefficiently encoded will be lost because they cannot be retrieved. The inefficient retrieval argument is that memories are lost because although they are stored properly, the search for them is inefficient. To return to the library analogy, it is as though a person with severe dyslexia were sent to find a book. This issue is of especial importance in discussing the memories of people with dementia (see Chapter 6).

Memory can be tested in a variety of ways. The commonest distinction is between recall and recognition. The former requires a participant to report as much as possible of a list of TBR items. In an ordered recall task, the participant is only marked correct if all TBR items are repeated in their exact order of presentation (e.g. TBR
items are 17654; participant must recall 17654; 71546, for example, is not sufficient).

In a free recall task, the order of recall does not matter (thus, 71654, 71546 , 56147, or any other permutation of these numbers would be equally acceptable). A recognition task is considered to be easier than a recall task. Both begin with a presentation

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of the TBR items. However, in a recognition task, the participant’s memory is tested by having to select the items he or she has seen (the targets) from a list which also includes items which were not on the original list, the distracters). Participants tend to remember more items in a recognition than in a recall task, because the memory load is lighter (it is also worth noting that the recognition and recall processes are almost certainly controlled by different mental mechanisms). In a cued recall task, the participant is in effect given a hint about the answer (e.g. he or she might be given the first letter or letters of the TBR word).

Having thus briefly considered some of the technical terms, theories and techniques employed in memory research, attention will now shift to how ageing affects memory.

Ageing and short-term memory (STM)

If a basic STM span test is administered (where the participant simply repeats back what the experimenter has just said or shown), then several studies have demonstrated a statistically significant, but nonetheless rather small decline in later life (Craik and Jennings, 1992; Craik et al., 1995). However, when any extra demands are placed on participants, then age effects generally become very much more pronounced (Cohen, 1996; Craik, 1986).

One method of making a STM task more complicated is the backward span procedure, where the participant is required to repeat the items back in reverse order of their presentation (e.g. TBR items are 75123; participant must reply 32157). This is clearly harder than straightforward recall, since participants must keep in store the items in their correct order whilst simultaneously working out what they are in reverse (in essence, this is a test of working memory). Bromley (1958), among others, has shown that older people are significantly worse at this task. Several causes have been suggested. One is that because the items in the forward and reverse lists are identical, it is easy to confuse the two, and thus form a garbled amalgam. Again, the older participants might lack the mental processing capacity of younger people, and simply not have the ‘processing space’ necessary to manipulate the TBR items. A refinement of this is to argue that the items are transferred to LTM for re-arrangement, because the slave systems’ memory capacity is too inadequate. Either items are lost during the transfer process, or the LTM in some manner fails to store the items efficiently. There is an important caveat to this. Some researchers use the difference between forward and backward spans as a gauge of ageing decline. However, Ryan, Lopez and Paolo (1996) argue that this is too variable between test sessions to be of

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value (whilst Gregoire and Van der Linden (1997) go further and argue that there is no age difference in the size of the effect).

The argument above that the decline of STM is due to a failure to use LTM as an effective backup is supported by the findings of Morris et al. (1990). They gave younger and older participants a conventional working memory task, in which they had to remember a short list of words whilst simultaneously deciding if a simple sentence was true or false (e.g. ‘sparrows can build nests’). The older participants’ subsequent recall of the words was significantly worse than the younger participants’, and the magnitude of this difference increased the more words had to be remembered at one time. Morris et al. argue that this age difference occurs because the younger participants not only encode information in their working memory, but also send a copy of the memory trace to a LTM store. If the memory trace is lost from working memory, the younger participants can retrieve a spare copy from LTM. Older participants, however, are less able to make a copy, either because they lack the ‘mental capacity’ to do it, or because their LTM is in some manner inefficient (see next section). Thus, if the memory cannot be retained in a working memory store, it either cannot be retained at all, or at best it is retained inaccurately. Note that the logical consequence of this argument is that it is possible that older and younger people may have equally efficient STM stores – the difference lies in the fact that older people may have poorer encoding and/or retrieval strategies.

Baddeley (1986) cites the central executive as the prime cause of this age-related decline. As evidence for this, one can consider the experiments on backward span and concurrent processing discussed above. Other studies have shown that increasing the complexity of the distracting task in a working memory task disproportionately affects older people’s recall (e.g. Morris, Gick and Craik, 1988). According to the working memory model, these processes are overseen by the central executive, which in older people is failing to combine memory and concurrent processing. Given that the central executive’s functions have been linked to the frontal lobes (see Baddeley, 1995), and given that frontal lobe problems are known to be a feature of cognitive ageing (see Chapter 2), this provides a plausible explanation. It is strengthened by the consideration that another problem with ageing STM is a failure to distinguish between redundant memories and TBR items (see e.g. Craik et al. , 1995; though see Jenkins et al. , 1999 for a possible criticism), also linked to declining frontal skills.

Again, Maylor, Vousden, and Brown (1999) present an ingenious model linking STM for serial order to a combination of frontal decline and response slowing. Findings such as these imply that a principal component of age-related decline in STM is in the processing of information, rather than the storage per se. It is thus not surprising

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to find that ageing changes in STM ability are strongly correlated with fluid intelligence (Salthouse, 1991b), speed of processing (Bryan and Luszcz, 1996; Byrne, 1998; Fisk and Warr, 1996), and more broadly, with other indices of central nervous system functioning, such as visual acuity (Salthouse et al., 1996). To this extent short-term/working memory decline may be seen as little more than part and parcel of general intellectual ageing.

However, this is not the only problem besetting older people’s memory skills. A study by Belmont, Freeseman and Mitchell (1988) suggests that older people may encode information in STM using less efficient strategies. This concerns a memory process called chunking. Given a long string (>4) of TBR items, a better strategy than trying to remember them as one long string is to think of them as a series of groups of 3 or 4 items. For example, instead of trying to remember 345172986142 as 345172986142, a better strategy would be to think of it in chunks of three as 345 172

986 142. Precisely this principle is used in the presentation of credit card and telephone numbers. Belmont et al. demonstrated that older people are less likely than younger people to chunk long digit lists when trying to encode them. However, it is worth noting that some older participants did chunk, and their spans were as good as the best of the younger participants. Other researchers have also noted that older people do not arrange TBR items, and that without prompting, they do not pay as close attention to them. In other words, they do not process the items ‘deeply’

enough (e.g. Craik and Rabinowitz, 1984; though note Salthouse, 1991b argues that evidence of age differences in depth of processing is equivocal because of methodological flaws in the studies concerned). Furthermore, older adults may at a broader level change their memory strategies. For example, Brebion, Smith and Erlich (1997) argue that when given a working memory task in which a set of TBR
items had to be remembered in tandem with performing a sentence comprehension task, the older participants tended to place greater emphasis on the comprehension than the memory task.

Perlmutter and Mitchell (1982) concur that older people have an especial problem in encoding material, but also note that ageing affects the retrieval and/or storage process. In support of this argument, they note that on some STM tasks, the older participants were disproportionately better on the recognition than the recall tasks.

Recognition is easier than recall, because the participant does not have to possess as clear a memory of the TBR item in order to get the right answer. This can be explained conceptually as follows (though no claims that this is actually what takes place in the brain are intended!). Suppose that older and younger participants are given the following list of TBR items:

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DUCK, CLOCK, TABLE, GLASS, PHONE, PACK

Suppose also that the younger and older adults encode the items equally well, and that any problems which arise occur after this stage, in either storage or retrieval (experimentally, it is difficult to distinguish between the two processes). Finally, suppose that any errors that occur consist of forgetting letters in the words (indicated by X s below). If the storage/retrieval of the older participants is worse than the younger participants’, then the memories they retrieve may be something like this: Younger participants: DXCK, CLOCK, TABLE, GXASS, XHONE, PACK

Older participants: DXCK, CLXCK, TABLE, GXASS, XHONE, PACK

In a recall task, only those items completely clearly retrieved can be recalled. Thus, the recall scores for younger and older participants would be 3 and 2 respectively.

However, in a recognition task, the participants can compare their ‘fuzzy’ memories (e.g. DXCK) with the items in front of them. If there is a strong correspondence between the fuzzy memory and a possible answer (e.g. DXCK and DUCK), then either the participants’ memories may clear (thereby recognising the X as a U) or they may make an educated guess. Either way, the older people’s performance should match the younger people’s, because a crystal clear memory is no longer de rigeur.

Following this argument a step further, it should be apparent that older people’s memory for items is not so much less, as slightly, but critically, more inaccurate.

Recognition cannot aid participants if they have no memory trace of a TBR item, or at best a very poor one (e.g. the memory trace of DUCK was XXCX). This is supported by a study by Parkin and Walter (1992), in which participants were asked to state if a word they claimed to recognise was one which they could distinctly remember, or if they ‘knew’ it was on the list, but had no clear recollection. The researchers found that the proportion of ‘definitely know’ to ‘just know’ answers shifted towards the latter with increasing age of participants. Furthermore, this shift was related to evidence of a decline in the functioning of the frontal lobes, thereby providing further evidence for a central role of this section of the cortex in ageing psychological change (see Chapter 2).

Belmont et al. and Perlmutter and Mitchell provide evidence that older people can encode and retrieve as well as younger adults, but they do not do so spontane-

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ously. If not deliberately prodded or aided into such strategies, then they choose less efficient methods of encoding and retrieval. Waugh and Barr (1982) also note that older people are less good at encoding if TBR items are presented quickly in succession (rather than slowly). This indicates that the encoding processes of older people are slower and less efficient. However, by Perlmutter and Mitchells’ own admission, the ‘younger participants’ used in their (and indeed most other researchers’) memory studies are college/university students, who are likely to be better versed in memory tasks (and hence using mental aides memoires) than community resident older people.

This places a question mark over these studies – are older people worse because of their age per se, or because of a cohort effect? The debate surrounding this issue has yet to be resolved, but from the combined longitudinal and cross-sectional research by Schaie and others (see Chapter 2), which have included memory measures, it appears that there are genuine age differences, but that these are in part the result of a cohort effect.

However, there is evidence that, with training, at least some age deficits can be overcome. One method is to train older people in the method of loci technique.

This involves memorising a series of mental pictures of familiar scenes, such as the rooms in one’s house. Each TBR item is mentally placed in a scene, and then the list is recalled by making an imaginary journey, recalling what was stored in each picture.

Suppose that one was given the list 15794 to recall. One might imagine entering one’s house. A 1 is sticking through the letter box, a 5 is in the umbrella stand. Entering the living room, 7 is sitting on the sofa, whilst next door 9 is helping himself to a large scotch. Going into the kitchen, 4 is peeling potatoes. The purpose of the technique is to make each image as vivid as possible, and accordingly, more memorable.

Smith et al. (1984, cited Rebok, 1987) using native Berliners as participants, found that they could increase their digit span by using familiar Berlin street scenes as loci.

Herrman, Rea and Andrzejewski, (1988) have also reported improvements in the memory of older participants after training, but noted that training only aided the particular memory task involved – the advantages did not transfer to other forms of memory. Improving digit span, for example, does not automatically aid recall of pictures. This effect has been noted in all age groups (i.e. it is not just a phenomenon of ageing). It must also be borne in mind that the method of loci technique is also used more efficiently by younger than older adults. For example, Lindenberger, Kliegl and Baltes (1992) found that older participants performed less well than younger controls on a method of loci task, even in comparisons of older experienced graphic designers (with good spatial skills) and younger people with no especial spatial skills.

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Ageing and long-term memory (LTM)

As mentioned in the Introduction, the ‘basic’ LTM and STM tasks are identical, save that the time gap between presentation of the TBR items and the request for their recall differs. Whereas the age differences in basic STM tasks are significant but quite small, there is a very pronounced effect in the case of LTM (Albert, 1988). This may not be very surprising, since much of the information passing into LTM must first be processed by STM, and any defects in STM may be magnified over the time items and stored in LTM prior to recall. Much of the recent work on ageing, however, has moved beyond the rather arid ‘laboratory studies’ of long-term retention of arbitrary lists of words and digits, to more realistic everyday memory tasks, and the chapter will concentrate on these.

Remote memory

Remote memory is for non-autobiographical events which have occurred within a person’s lifetime. It is usually tested by giving participants a list of names and/or descriptions of events which have been ‘in the news’ over the past fifty or so years, and asking them to indicate which they can remember. Several obvious precautions are taken by test designers. First, to prevent people getting full marks simply by saying ‘yes’ to everything, a few fictitious names and/or events are included in the list (‘Prince Babylon’, ‘The assassination of King Marvo of Ruritania’, etc). A more pressing problem is ensuring that the participants are genuinely recognising a remote memory, and not a more recently stored piece of information. To take an example: Most English people aged over 40 can remember England winning soccer’s World Cup in 1966 (they beat West Germany in the final by four goals to two). Therefore, asking a question such as ‘Did England beat Germany 4–2 in the 1966 World Cup final?’ might seem to be a sensible item to include in a remote memory test. However, it is very improbable that people responding correctly do so by consulting a memory laid down in 1966 and not consulted since. This is simply because highlights of the event have been replayed very frequently on television ever since. Hence, a participant could answer ‘yes’ to the question based on seeing a broadcast the previous week. Likewise, a participant aged under twenty, who could not possibly have seen the match as a live event, would also be able to answer correctly. By analogous reasoning, any event which is ‘too famous’ must be excluded from a remote memory test, because it is more properly part of general knowledge.

To escape this problem more obscure names and events must be chosen. If too obscure items are chosen, then one has the reverse problem that nobody has heard of

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them. Luckily, the media has an agreeable habit (as far as experimenters are concerned) of making some people very famous for a brief while, after which they sink back into obscurity once more. This is in no way to belittle their achievements – often they are considerable – but the inevitable hunger for news of the arrival of new champions in their field of endeavour causes a shifting of attention. The Famous Names Test, or FNT (Stevens, 1979) is a test which uses these ‘briefly famous’

names. It comprises a list of names of people such as John Conteh, Sid Vicious, Issy Bonn, and Reggie Whitcombe. Any reader aged over forty may recognise the first two names, but unless he or she is over seventy, it is improbable that they will recognise the final two (John Conteh was a boxer, Sid Vicious a punk rocker, Issy Bonn a music hall ‘comedian’, and Reggie Whitcombe was a golfer). The argument is made that since their period of fame, the above names have not been frequently mentioned in the media. Thus, if people recognise a name, it is because they are recalling a genuinely remote memory, and not just recalling the name being mentioned in a recent media presentation. To assess the depth of a person’s remote memory, the names on the FNT can be divided into categories: namely, those famous in the 1970s and 1960s, the 1950s, the 1940s and the 1930s (plus a group of very famous names such as Winston Churchill, whose non-recognition might indicate dementia). A number of fictitious names are included to prevent cheating.

Stuart-Hamilton, Perfect and Rabbitt (1988) tested participants aged 50–80 on the FNT, and found that for all ages, memory of recent names was better than for distant ones. This phenomenon has been observed by many other researchers (e.g.

Craik, 1977; Perlmutter, 1978; Poon et al., 1979), and contradicts the once popular Ribot’s hypothesis (Ribot, 1882). This argues that in older people, memory for recent events should be worse than for remote ones. A useful analogy is to think of the brain as a long deep tank, into which memories, in the form of water droplets, are deposited. Obviously, it takes a long time for the tank to fill, but when it does, water starts to flow over the edge of the tank and is lost. This overflow is likely to be composed of recently deposited water which is lying on or near the surface: the older deposits deeper in the tank are unlikely to be much disturbed and hence are not lost. In a similar manner, Ribot’s hypothesis argues that recently-deposited memories are more likely to be displaced because they are not sufficiently ‘bedded in’. However, experimental evidence indicates that it is the remote, not the recent memories which are lost.

In terms of the number of names correctly recognised, the FNT is a rare example of a psychological test in which older outperform younger participants. Having acknowledged this, there are problems in accurately interpreting what the findings

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mean. The most serious difficulty is that the youngest participants in the Stuart-Hamilton, Perfect and Rabbitt study were in their fifties when the experiment was run ( circa 1987), and thus would be hard pressed to remember the earliest names on the FNT (from the 1930s). In a second experiment by the authors, the FNT was given to twenty year olds, who could not possibly know the older names except as

‘historical’ figures. However, they could still accurately recognise about 25 per cent from each decade group (the participants correctly rejected all or most of the false names, so they were not simply guessing). This means that a proportion of items on remote memory tests are probably recognised from semantic memory rather than as genuine ‘only experienced at the time’ remote memories. In short, remote memory tests may in part assess remote memory, but the answers are heavily contaminated with recollections from a store of general knowledge. Furthermore, the relative likelihood of a particular name on the FNT being recognised was relatively similar for participants of different ages. In other words, if ‘Miss X’ was the tenth-most recognised name amongst participants in their seventies, Miss X was likely to be at or around tenth position amongst sixty-, fifty- and twenty-year olds (Stuart-Hamilton, Perfect and Rabbitt, 1988). This suggests that supposedly ‘remote’ names may be rather more frequently aired in the media than researchers suspect, and the similar

‘league tables’ of popularity for different names implies that the impact of media coverage is remarkably consistent for different age groups. Thus, whilst remote memory may exist, testing it remains fraught with difficulties, and measuring it in a

‘pure’ form, uncontaminated by general knowledge, is probably impossible.

Eyewitness testimony

As the title suggests, eyewitness testimony refers to the ability to remember information about an incident which has been seen once. In ‘real life’, eyewitness memory forms the basis of many legal cases, and experimental measures of eyewitness testimony have tended to present participants with an enacted incident (either ‘in the flesh’ or on video tape). Generally, older people are found to be as good as younger adults in remembering the main points of an incident, but to show some worsening of recall of relatively minor points, such as details of the clothing of the protagonists (e.g. Adams-Price, 1992). If a simple ‘score’ of overall information recalled is made, then there is an appreciable age difference (e.g. Yarmey and Yarmey, 1997). This does not bode particularly well for the credibility of older adults as eyewitnesses. Such a feeling is not enhanced by the findings of Coxon and Valentine (1997). They directly compared the responses of older and younger adults and

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children to a series of misleading and non-misleading questions about a crime video they had witnessed. It was found that both the older adults and children performed less well than the younger adults. Furthermore, the older adults answered fewer correct questions than the children. In compensation, they gave fewer incorrect answers, and were as relatively immune to the misleading questions as were the younger adults. In part, the problems of older people’s eyewitness memories may be perceptual deficits. Certainly, when these are controlled for, then at least some age differences are reduced or removed (see Searcy, Bartlett and Memon, 1999).

Specific features of eyewitness recall also show age differences. For example, one of the key features of eyewitness testimony is remembering the source of a particular event or utterance (e.g. who said what). Ferguson, Hastroudi and Johnson (1992) demonstrated that older people have greater difficulty in remembering the source of an item. The participants listened to sets of spoken words played over a stereo system, and had to remember which speaker produced particular words. The older participants found this harder to do when both speakers played voices of the same sex, and although advantaged by having different sex voices in either speaker, other permuta-tions worsened recall (although they improved the recall of younger participants).

This implies that the older participants cannot make use of the same range of information as the younger adults. Although not an eyewitness memory experiment, these findings have an obvious link to issues of recall of detail from different locations and persons. Again, in a review of the literature, Cohen and Faulkner (1989) note that older people are more prone to believing that an interpretation of an event is the actual memory of the event (see also Kensinger and Schachter, 1999). This means that there may be a greater danger of the memory of an event being distorted to fit a subsequent interpretation, thereby removing the objectivity of an eyewitness account.

Such considerations paint a grim picture of the status of an older person as a witness in a courtroom. Even if he or she is correct in the main points of their testimony (which arguably may be all that matters), a lawyer may quickly discredit this by playing on weaknesses over (what are after all irrelevant) recall of details (thereby reducing the older person’s self-esteem as well). Brimacombe et al. (1997) found that generally older eyewitnesses’ testimony was rated as less credible by observers (though they did not regard older people as being any less honest).

However, if people read statements in which the age of the witnesses had been manipulated (i.e. there were statements which were really by younger adults ostensibly provided by older adults and vice versa) then judgements of accuracy tended to go with the perceived accuracy of the statement rather than the perceived age of the witness. In other words, it is the content rather than the stereotype of older

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people’s eyewitness accounts which may provoke a negative judgement. Although this presents a rather gloomy picture, it should be stressed that the effects reported are only average and not applicable to all older adults.

Text recall

Because recall of text is strongly linked with linguistic skills, this topic is dealt with in detail in Chapter 4. A summary of the findings is that, essentially, there are no or relatively few age differences in the recall of the main points of a story (the ‘gist’ of the text) but that memory for details may worsen, especially in older people who are also low scorers on intelligence tests. However, there are a number of occasions when this rule breaks down, and interested readers should consult the appropriate section in the next chapter.

Semantic memory

Semantic memory might be expected to survive ageing in a fairly robust state, because memory for facts and information is part of the definition of crystallised intelligence, which is known to be relatively age-invariant (see Chapter 2). Indeed, this appears to be the case – in general, older adults are as good as, if not better than, younger adults at recalling facts and information held in semantic memory (e.g.

Camp, 1988; Fozard, 1980; Sharps, 1998). However, there are some caveats to this.

First, Craik et al. (1995) in a review of the literature concluded that whilst this is true for existing memories, storage of new semantic memories may be somewhat worse.

Again, ability to retrieve items from semantic memory may not be as fluent in later life. For example, Kozora and Cullum (1995) found that producing examples of particular semantic categories was less efficient in older adults. In a similar vein, it was noted in Chapter 2 that many older people’s definitions of words, whilst correct, were less exacting. Furthermore, Hultsch et al. (1992), in a three-year longitudinal study, found a significant decline in general knowledge for world events (along with declines in other memory and intellectual measures). However, this may in part have been a cohort effect.

Perhaps of greater interest to researchers is how older people gauge the accuracy of their responses, a process known as metaknowledge, or feeling of knowing (FOK). A typical FOK experiment might require participants to look at a question and then declare how confident they are that their answer is correct. For example, a participant might be confronted with the following:

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QUESTION: What is a pangolin?

HOW CONFIDENT ARE YOU ABOUT GIVING THE CORRECT

ANSWER TO THIS QUESTION?

1. Complete guess

2. Educated guess

3. Fairly confident

4. Completely confident

PLEASE GIVE YOUR ANSWER

Several researchers have shown that participants are quite accurate in their judgements. Namely, the more confident they are that they are right, the greater the probability that they are right (though a curious exception is eyewitness memory, where FOK scores are uncorrelated with accuracy – Perfect and Hollins, 1999).

There appears to be no age difference in FOK accuracy (e.g. Fozard, 1980; Perlmutter, 1978). However, although this may be the case, older people do not necessarily believe it. For example, Camp (1988) reported that older adults thought their semantic memory had declined. Other researchers have similarly found low self-confidence in older participants (e.g. Botwinick, 1967). How justified these feelings are will be examined further in the section on metamemory below.

Implicit memory

Evidence on implicit memory points to there being no significant age difference, or, at worst, only a slight decline (Craik and Jennings, 1992; Gaudreau and Peretz, 1999; Light and Singh, 1987; Salthouse, 1991b). Park and Shaw (1992) argue that in studies which have found an age difference, it has not been established if the younger participants had realised that they were taking part in a memory test, and so deliberately concentrated harder on the TBR items. Park and Shaw cite the work of Light and Albertson (1989) which found that, if aware participants were excluded from the analysis, an age difference in implicit memory performance disappeared.

Park and Shaw’s own study found no evidence for an age difference on a word completion task ‘regardless of whether [participants] aware of the memory test were

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included or excluded’ (Park and Shaw, 1992; p. 632). Jennings and Jacoby (1993) demonstrated that implicit memory was preserved, even when a distracter task was employed (though explicit memory worsened).

Some manipulations of implicit memory tasks do induce age differences, however. For example, Harrington and Haaland (1992) gave participants the task of performing various hand movements. These were either performed in a repetitive set sequence or were done in random sequences. It was anticipated that the regular repetition should aid implicit memory far more than the random sequences. The researchers found that this was true for younger participants, but older adults showed no difference between the two conditions. This implies that older people are less able to make use of implicit information, although note that another study showed that placing an explicit order on a physical act through list organisation improved older participants’ explicit memory for the act (Norris and West, 1993). Again, as was seen in Chapter 2, although subject to experimental artefacts, it has been found that older people are less capable of implicitly learning that a target will appear with greater frequency in some locations than in others in a visual search task. However, countering this is the finding that older people are disadvantaged to the same extent as younger adults when a regular predictable sequence of stimuli in a reaction time task is replaced with a random sequence (Howard and Howard, 1992).

Another caveat is raised by McEvoy et al. (1992), who found an apparent worsening of ability to use implicit information. In one of their experiments, they gave participants a set of words to remember, and then tested recall using cues (in this case, words related in meaning, e.g. if the TBR word was ‘butter’ then the cue might be

‘bread’). For the younger participants, recall was worse if the TBR word had a lot of potential associates (e.g. ‘car’ has lots of associates, ‘basilisk’ very few). This was also true for the older participants, but the size of the effect was significantly diminished.

This, it is argued, indicates that older people are less able to make use of implicit associations. It is probable, however, that the older participants took longer to respond (no response latencies are recorded by McEvoy et al.). Therefore, the effect of the implicit associations may be diluted by the extra processing time.

Although implicit memory may in many instances be unaffected by ageing, there would appear to be other occasions where it is not (although this is not true for every instance of the same general experimental paradigm). This may provide support for Salthouse’s (1991b) suggestion that age differences may be found in implicit memories for some materials, but not for others (see also Cohen, 1996). However, it may also be the case that implicit memory is better preserved where the participants simply have to receive information passively, and that a decline occurs only when

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some additional processing has to be done to make use of the implicit information. In other words, an age difference only appears when processing demands increase beyond a certain level, which is a familiar refrain in psychogerontology. However, until more evidence is gathered, this is a moot point.

Autobiographical memory and ageing

Several major problems beset autobiographical memory research. The most often-cited of these is the issue of reliability. For example, an older participant may reminisce about a picnic in 1936, held with her now dead parents. How can one possibly verify the accuracy of this recollection? This is not to say that the participant is deliberately lying but usually, reminiscences have been recalled many times over a person’s lifetime, and with each retelling, details alter to improve the flow of the narrative (Bartlett, 1932). Thus, the recounting of a story five years after the event in question may have the same basic plot as a retelling fifty years on, but the details of the two narratives are likely to be different. This argument is supported by the findings of a longitudinal study by Field (1981). Comparing reminiscences of the same events 30 and 70 years, on, there was a reasonably high correlation for points in the basic plot (r = 0.88), but only a 16 per cent concordance for recall of more peripheral details (r = 0.43).

Another serious methodological flaw concerns how the memories are elicited.

Asking participants for their most vivid memories produces a glut of reminiscences from the early part of their lives. So does giving participants a cue word, and asking them to produce a reminiscence associated with it (e.g. JAM - ‘Oh yes, I remember helping my mother make jam when I was a child’), provided the participant has to put a date to each memory after producing it. However, if the participant is allowed to produce a whole list before any dating of memories is done, then the bias shifts in favour of a preponderance of memories from the recent past (Cohen, 1989). To further muddy the waters, words which are rated high in imagery-provoking properties tend to generate older memories (Rubin and Schulkind, 1997b). Thus, how the participant is asked determines the age of memories produced, and there is certainly no evidence to support the cliché that older people live in the past. Indeed, many studies have shown that younger and older adults produce equal numbers of reminiscences from childhood (e.g. Cohen and Faulkner, 1988; Rubin and Schulkind, 1997a). This is not necessarily due to participants wallowing in nostalgia. Rabbitt and Winthorpe (1988) found that, when memories are divided into ‘pleasant’ and ‘unpleasant’, reminiscences from early life fall predominantly into the latter category. Another problem

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is that participants may censor their memories. It is a reasonable assumption that, human nature being what it is, people’s most vivid memories include a largish proportion of sexual experiences. Curiously, these seem to be rarely mentioned by participants.

Notwithstanding the above considerations, the reminiscence peak (a.k.a. reminiscence bump) has been reported by many researchers. This is the phenomenon that when due allowance is made for testing methods, most autobiographical memories are likely to come from the period when the individual was between 10 and 30
years-old (e.g. Rubin, Rahhal and Poon, 1998). This is not surprising, since this is the time when most of the key life events (first forays into sex, employment, exams, marriage, parenthood, and so forth) occur (see Jansari and Parkin, 1996). However, the largest proportion of memories tend to be from the most recent decade of a person’s life (Rubin and Schulkind, 1997a). In contrast, autobiographical memories from the very early years are scarce or non-existent (childhood amnesia). Freud and his fol-lowers believed that this was due to suppression of unpleasant memories and psychoanalytic conflicts, but it is now felt to be because young children lack the mental facilities to encode retrievable autobiographical memories.

An issue related to what is remembered is the vividness of the recall. Introspection shows that some memories are clearer than others, and generally, earlier memories are perceived as ‘dimmer’ than later ones (Cohen and Faulkner, 1988). This was also demonstrated by Nigro and Neisser (1983), who found that distant memories are usually perceived as if watching the events taking place as a bystander (i.e. as though watching oneself ), while more recent events are remembered from one’s viewpoint at the time. Furthermore, the reasons why an event is perceived as vivid change across the lifespan. Cohen and Faulkner (1988) found that younger and middle-aged adults were affected by how emotionally charged the event was - the greater the feelings, the greater the vividness. For older adults, the biggest cause of vividness was how often they had thought about the event subsequently. Cohen and Faulkner suggest that, because ageing blunts the vividness of memories, it is only by rehearsing them that their details can be retained (rather like taking pieces of silverware out of the cupboard to polish them, to prevent them tarnishing). Why memories lose their perceived vividness is still open to debate. However, given that ‘vividness’ is a subjective measure, it is possible that as people become more world-weary with advancing age, so they become more jaded in their reminiscing. Another possibility is that a decline in LTM causes people to forget details of a memory, and it becomes less clearly focussed as a result. In turn, this is interpreted subjectively as a loss of vividness.

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Rabbitt and Winthorpe (1988) note that older people are generally slower to produce reminiscences. Indeed, in general, older people give poorer quality responses in autobiographical memory tests. For example, they provide vague rather than specific answers (e.g. ‘I remember going on a picnic when I was a child’ as opposed to ‘I remember going on a picnic on Salisbury Plain on my seventh birthday’).

However, Winthorpe and Rabbitt (1988) demonstrated that this was not due to ageing per se, but to the coincidental decline in fluid intelligence and working memory (which is used to keep track of what has been said and what needs to come next in the narrative). In a subsequent study by the researchers, it was found that detail in the reminiscences was determined by age, fluid intelligence and crystallised intelligence (Holland [nee Winthorpe] and Rabbitt, 1990; Phillips and Williams, 1997 report analogous results). This was interpreted as meaning that although the ageing process and the fall in fluid intelligence cause a decline in reminiscence skills, the age-invariant crystallised skills may to some extent compensate for this.

Moving away from consideration of quantities of autobiographical memories, it is worth noting that reminiscence can have a therapeutic effect. Some commentators believe that ‘reminiscence therapy’ for older people should be encouraged, since it enables them to come to terms with their lives (Kermis, 1983). However, for many older people, reminiscence may be a response to boredom:

‘Older people may experience an increasing contrast between an unmemorable present and an eventful past. Remote events may be more often researched and rehearsed in memory as the theatre of the mind becomes the only show in town.’

(Rabbitt and Winthorpe, 1988; p. 302).

Prospective memory

As many recent textbooks have noted, one of the principal functions of memory is not to remember the past but to plan for the future. In part this means learning from one’s experiences and mistakes in order to cope better with situations when they next arise. This can be considered as part of wisdom/crystallised intelligence. Another, more literal aspect is prospective memory, or the ability to remember to do something in the future. It might be supposed that prospective memory is simply another form of LTM, since it involves retaining information over a long time period. However, there is ample evidence to disprove this notion. First, on theoretical grounds, the two memory types are distinct. In retrospective memory, it is sufficient to recall an item or event for the action to be considered a success. In prospective memory, however, the item can be recalled any number of times, but it is only successful if the person

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remembers to do it at the right time and acts upon it (West, 1988). A second consideration is that the memory types are empirically distinct, with little correlation either in accuracy or in types of mnemonic strategies used (Jackson, Bogers and Kerstholt, 1988; Kvaviloshvili, 1987; Wilkins and Baddeley, 1978).

Methods of recall in prospective memory vary greatly between individuals, but, broadly speaking, they can be divided into two classes – internal and external strategies/cues. External cues are such familiar things as entries in a diary or the knot in the handkerchief. In other words, prompts which the person places in the external environment. Some experiments test the use of these strategies through event-based tasks (where the participant must retrieve and act on a memory when given a particular prompt). Internal cues, on the other hand, are purely mental strategies, where the person hopes to prompt him– or herself at the appropriate time. This may be measured through time-based tasks (the participant must respond at a particular point in time). This division is not as clear cut as some commentators seem to suppose, however. For example, a common strategy is to remember to do something in conjunction with a familiar daily routine, such as the habitual breakfast coffee (Maylor, 1990a, Appendix A). Is this an internal strategy (simply remembering to add another action onto the end of a familiar sequence) or an external one (the sight of the coffee acting as an aide memoire)? Similarly, an external cue such as a diary entry requires an internal strategy to remember to look in the diary. Therefore, the functional distinctions between the mnemonic methods are blurred, and certainly are too ambiguous to bear deep analysis. Therefore, for the rest of this section, internal and external methods will be treated purely as practical strategies, avoiding the question of how they work.

In certain kinds of prospective memory tasks, there is either no age difference or even an ageing superiority. For example, a ‘traditional’ prospective memory task requires participants to remember to phone the experimenter at prearranged times.

Poon and Schaffer (1982, cited West, 1988) and Moscovitch (1982) found that the older participants remembered to phone more often and they were more punctual.

However, this could in part be a cohort effect. Older people may lead more sedate lives and thus have less to distract them from making phone calls. Again, they might have been brought up to place greater emphasis on punctuality and keeping appoint-ments than younger people and thus were more motivated to make the calls. This latter supposition is supported by Poon and Schaffers’ finding that increasing the monetary reward for making a call improved the older people’s performance, but not the younger people’s. One method of minimising the cohort effect is to take participants in their fifties as the younger adult group. This age group will still intellectually

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perform more or less on a par with adults in their twenties (the age of a typical ‘younger adult’ group) but are more similar to older adults in their upbringing. Maylor (1990a) did this, and furthermore selected participants who had similar lifestyles.

The participants had to phone once per day for five days, either at a specific time (the

‘exact’ condition) or between two specified times (the ‘between’ condition). Maylor found no significant difference between age groups in punctuality nor in number of calls remembered. She also found no age difference in the cues used to remember to make the calls. This contradicts earlier findings that older adults tend to use more external cues (e.g. Jackson et al., 1988; Moskovitch, 1982). Possibly this reflects a cohort effect. Studies other than Maylor’s have often used students as younger participants, who may be forced to take part in experiments as part of their degree programme (much psychological research takes place under the guise of practical classes). Given the typical undergraduate enthusiasm for practicals, the younger participants may be apathetic, and they may use internal cues because it is less effort than creating external reminders. Maylor’s study used younger participants who were all active volunteers in an ongoing large scale programme into the effects of ageing, and thus they were probably more motivated.

Maylor did find an age effect, however, in the efficiency with which participants used external and internal cues. Namely, internal cue users who made errors were significantly older, and external cue users who made errors were significantly younger.

Thus, those participants who continue to rely solely on their memories worsen, whilst those who turn to external aids improve (probably because they become more practised). However, to some extent participants use strategies according to the task at hand. Maylor found that the ‘between’ condition generated greater use of external cues than did the ‘exact’ condition. She suggests that this is because of the perceived difficulties of the two tasks (i.e. the condition thought to be harder demands a more positive response in the shape of preparing an external cue). West (1988) has reported similar links between cue use and task demands.

However, under other circumstances, there are considerable age differences in prospective memory. For example, Cockburn and Smith (1988) found that older participants were worse on tests of remembering an appointment and remembering to deliver a message. Again, West (1988) demonstrated that older participants were significantly worse at remembering to deliver a message during a test session. Indeed, in general, if participants must remember to do something as part of other measures, then there is an age difference. Furthermore, age declines tend to increase with the increased complexity of the task (e.g. Einstein, McDaniel and Guynn, 1992) and/or its attentional demands (Einstein et al., 1998). Why older people should be better at

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some prospective memory tasks than others remains an open issue. It has been suggested that older adults are better at event-based tasks than time-based tasks. However, ignoring the criticism of this classification presented above, the findings of Maylor (1998) militate against a simplistic interpretation of this. Maylor found significant age differences in a task requiring participants to identify pictures of famous people, with a prospective memory component requiring participants to identify those people wearing spectacles. Thus, the experiment provided strong event-based cues, but there was an age difference. Again, Park et al. (1997) has plausibly argued that under some circumstances, time-based tasks may be measuring time monitoring rather than memory per se.

Perhaps a more satisfying explanation is derived from Craik et al.’s (1995) observation that prospective memory tasks tend, perversely enough, to be most prone to age differences over relatively short time frames. Thus, if asked to do something as part of a fairly complex ongoing task, then this is more likely to be forgotten than, for example, remembering to do a single act in a week’s time. It is questionable whether the relatively long-term and naturalistic and relatively short-term and laboratory-based paradigms are assessing the same types of prospective memory. For example, suppose a person is asked to play a particularly taxing video game of the ‘shoot

‘em up’ variety, and told that every time they shoot a red monster, they should shout out ‘bananas’. If they forget to call out every time they kill a red monster, is this due to forgetting to do something in the future, or a lapse in performing just another component of the ongoing task (akin to forgetting that, e.g. shooting the yellow monsters gets double the points of shooting the blue monsters?). In comparison, forgetting to phone the experimenter at a particular time on a particular day is more likely to be a memory lapse rather than distraction by a large number of demands competing for the participant’s attention at precisely the same moment in time. It should be noted that the demands of the short-term prospective memory tasks need not (in subjective terms) be onerous to induce an age difference. For example, Maylor’s (1998) task could not exactly be described as difficult. Again, Maentylae and Nilsson (1997) found older people were significantly less likely to remember to do the even simpler task of asking an experimenter to sign a paper at the end of a 2- hour test session. Another consideration is that longer-term tasks, such as remembering to phone someone on a particular day and time can be integrated into the general routine of daily life and thus become part of a well-practised procedure. However, doing concurrent tasks or delivering messages during meetings with researchers is not something at which older adults have had much practice. In short, current research on prospective memory in ageing may be encompassing two rather different phenomena under a

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blanket heading. Intelligence, however, is not a particularly strong predictor for either type of study (Cockburn and Smith, 1988; Maylor, 1993; 1998).

Metamemory and ageing

To what extent can older people gauge their mental abilities? The answer to this question seems to depend very much on the type of memory being considered. In a FOK study, the participant is required to judge the suitability of an item he or she has already retrieved from memory: in other words, passing judgement on a memory act already completed. In this case, it appears that ageing has little effect (see the Semantic Memory section above and Perlmutter, 1978). Likewise, there is little effect of ageing when judging relatively abstract features of memory, such as deciding on which types of TBR items are easiest to remember and the best mnemonic strategies to use (Perlmutter, 1978). However, other aspects of metamemory do show an age-related decline. Principally, age differences occur when: (a) judgements are asked on a memory act which is incomplete, or (b) global judgements on past and future performance are required. Furthermore, as will be seen below, methodological problems with the test of the latter in any case make much of the research literature uninterpretable in any case.

A prime example of an incomplete memory act is the tip of the tongue (TOT) state (for readers pursuing matters further, note that some commentators classify TOT as part of semantic memory rather than metamemory). This is a familiar experience for most people. The word one is searching for cannot quite be recalled, yet one can remember some features of it, such as the first letter, the number of syllables, words which sound like it, and so forth. Brown and McNeill (1966) were the first to investigate this phenomenon intensively, by giving participants definitions of obscure words, and asking them to provide the words. Often, participants either knew the word or simply had no idea, but on some occasions a TOT state was generated.

Typically, participants could indeed provide details of the word (e.g. 57 per cent of the time they could identify the first letter). The TOT state is nothing more than an annoyance when confined to defining rare words. However, if it creeps into everyday speech, then it is a potential handicap. Burke, Worthley and Martin, (1988) decided to study the TOT state in older people, in part because older volunteers in a study the experimenters were running had complained about it being a problem. Indeed, in general older people can be bad at remembering words, and especially names (Crook and West, 1990). Burke et al. asked their participants to keep diary records of all TOTs over a four-week period. They were asked to record all the details of the word

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they could remember whilst in the TOT state, and whether they ever discovered what the word they were searching for actually was (i.e. whether the TOT resolved itself). Burke et al. found that the older participants reported significantly more TOTs, although there was no age difference in the proportion of resolved TOTs (over 90 per cent of the time both age groups eventually found the word they were looking for). However, whilst in the TOT state, the younger participants could report significantly more details of the word (a finding echoed by Maylor, 1990b).

There was also an age difference in the types of words which generated TOTs. Both younger and older participants has the greatest difficulty with proper nouns, but for the remainder, older people had the greatest difficulty with the names of everyday objects and younger people with abstract nouns. A final difference the researchers noted was that younger volunteers tended actively to search mentally for the desired word, or even ask someone else for help, whilst the older participants usually simply hoped that the word would ‘pop up’ (though some did try the same strategies as the younger participants).

In a similar study, Cohen and Faulkner (1986) had participants complete a two-week diary of TOTs for proper nouns (i.e. names). Surprisingly, the majority of these (68 per cent) turned out to be for names of friends and acquaintances. Perhaps, as Cohen (1989, p.104) notes, ‘there are more opportunities to forget names that are in frequent use’ (though it seems unlikely that memory for names is disproportionately disadvantaged in later life, as a careful analysis by Maylor, 1997, demonstrates).

Again, older people seemed to rely on a strategy of waiting for the name to ‘pop up’.

Given these findings, one can surmise that older people have a problem with retrieving faint memory traces. This can be seen in the facts they have more TOT states and that when in a TOT state, they have fewer details of the word. Because they lack many details of the target word, it is probably not worth their while to search for it on the basis of the little information they have available (the product of a metamemory strategy?). Conversely, younger people, who can identify more about the word in a TOT state, and thus have more information to act upon, will probably find it worthwhile to indulge in a search of their memories.

A further aspect of metamemory is what a person knows about the general state of his or her memory. Typically, this is assessed by requesting participants to complete a self-report questionnaire. This includes assessments of everyday memory competence (e.g. from 1 for ‘poor’ to 5 for ‘excellent’), and asks participants to estimate how often they forget things from the important (such as an appointment) to the trivial (such as going into a room to fetch something and forgetting what one went in for). Results from such studies have been conflicting. Some studies have found older

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people reporting a decline in their abilities and a concomitant rise in acts of absent-mindedness, and so forth (e.g. Perlmutter, 1978). Other researchers have found the reverse – namely, it is the younger participants who report a greater number of memory lapses (e.g. Baddeley, 1983; Rabbitt and Abson, 1990). To gauge the accuracy of participants’ metamemories, scores on questionnaires are often correlated with a battery of tests of memory spans and often other psychological measures as well. The relationship between questionnaire scores and memory spans is similarly muddled. Many researchers report a poor correlation between self-predicted performance and actual memory skills (e.g. Herrman, 1984; Rabbitt and Abson, 1990; Zelinski, Gilewski and Schaie, 1993). However, others have found a correlation (e.g.

Maylor, 1990a). Taylor, Miller and Tinkleberg, (1993), in a longitudinal study, found a correlation at a group level between some memory scores and self-report (but not with a measure of fluid intelligence). However, when individuals were considered, then no significant effect was found.

Why is there this confusion? The answer lies in the methodologies used. First, people are notoriously bad at quantifying their abilities (hence the need for professional psychologists!). Rabbitt (1984) observes that a person can only judge how his or her memory is by comparing it with that of other people. But whom? Younger people (or him–or herself when younger)? Contemporaries? An idealised hyper-intelligent being? Participants may differ markedly in their value judgements because they are using a variety of models to form their judgements, and hence, they are not being gauged against a common scale.

A related problem concerns self-image. Older people often expect to be forgetful, younger people do not. Accordingly, older people may be more sensitive to memory lapses, and so unrealistically downgrade their abilities. It is not surprising to find there is a correlation between older people’s self-ratings of forgetfulness and their level of depression (Collins and Abeles, 1996; Cipolli et al., 1996; Rabbitt and Abson, 1990; Thompson et al., 1987). Another frequent criticism is that, perversely, questionnaires may still overestimate the memory skills of the least mnemonic participants. Information about a participant’s memory comes only from them; there is usually no corroborating evidence. However, with the self-confessed forgetful, how can they remember all that they have forgotten? This is an ingenious and untestable argument. However, there are some indications that it is overly-pessimistic, since several studies involving the spouses of participants have found a good correlation between self-reported memory skills and spouses’ estimates of the same (Cohen, 1989). However, even the most fervent supporter of the questionnaire method would admit that there will inevitably be some inaccuracies in self-ratings.

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The generally poor correlations between self ratings and actual memory spans probably arise because usually questionnaires ask participants how their memories are in real life, whilst spans are taken from tests run under laboratory conditions. For example, most ‘standard’ memory tests assess a single type of memory in quiet unstressful conditions. In real life, such opportunities rarely arise (Cohen, 1989; Rabbitt and Abson, 1990), and Jonker, Smits and Deeg (1997) have noted that for many older people simple anxiety about taking a memory test may be as important a predictor as metamemory.

It is also worth observing that, under realistic conditions, many memory lapses may not be due to memory at all. For example, Tenney (1984) found that a frequent cause of older people misplacing items that they had literally overlooked the said items in a systematic search for them. In other words, the problem is often one of misperception rather than memory per se (though note that memory for spatial location is significantly worse in later life – Uttl and Graf, 1993). Rabbitt and Abson also note that in general, the correlations between memory tasks are poor anyway. For example, training participants to be good at one type of memory task in no manner improves their performance on others, as noted above. Therefore, expecting to find a general all-embracing metamemory measure which will simultaneously predict all types of memory is a misplaced ideal: there is no memory equivalent of intelligence’s g. In studies such as Maylor (1990a), which have reported a correlation between self-report and degree of failure, the effect is usually due to specific items on the questionnaire, rather than overall score.

Summary and overview – how does ageing affect memory?

Alas, the familiar complaint of many older people that their memories ‘aren’t what they used to be’ seems in the main to be justified. Memory does decline in later life, and despite a few areas of relative preservation (e.g. ‘basic’ STM span and some aspects of metamemory), the outlook is downwards. However, although there is a general trend, a general principal does not seem to underlie it, since there is a poor correlation between different types of memory. For all these considerations, it seems plausible that some factors must be more important than others in predicting age-related memory loss. For example, emotional state, socio-economic background and level of education have been suggested as plausible determinants of intellectual skill (see Chapter 2). West et al. (1992), in an impressively large study of nearly two and a half thousand participants, assessed performance on a wide variety of ‘realistic’

memory tasks (remembering people’s names, face recognition, and so on). The

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researchers also took measures of chronological age, ‘vocabulary, education, depression, gender, marital status, and employment status’ (West, Crook and Barron, 1992, p. 72). Perhaps not surprisingly, vocabulary level (also indicative of general intelligence, and crystallised intelligence in particular) accounted for a measure of prose recall, and also generally accounted for some of the variability in performance of other memory tasks. Gender proved a significant predictor of memory tasks in which participants had to memorise a grocery list. Women participants were better, though given traditional gender roles, this is not surprising (note that Larrabbee and Crook, 1993 found that memory for such stereotypically ‘female’ tasks showed a gender bias across the lifespan, and was not disproportionately altered in later life).

However, with these exceptions, chronological age was the best predictor of memory performance, and overall was unquestionably the best.

In a three-year longitudinal study, Zelinski et al. (1993) took a rather smaller sample (508 men and women, of whom 227 were available for retesting) and assessed the relationship between memory, vocabulary, and tests of ‘higher reasoning’ (essentially, fluid intelligence). Measures of length of schooling and other biographical data were also taken. The researchers found a less clear-cut picture than West et al. Although age was a good predictor of performance on some memory tasks (especially for participants who displayed a very marked decline), ‘higher reasoning’ also had a significant effect independent of any influence of age. This should not be surprising, if one recalls Rabbitt’s caveat, cited in Chapter 2, that practically any intellectual decline can be linked to a fall in fluid intelligence (as Zelinski et al. acknowledge). However, the authors found that age had a strong relationship with memory decline which could not be attributed to the coincidental effects of changes in fluid intelligence. Probably the most parsimonious explanation of the results is that there is no parsimonious explanation of the results. It would, however, be surprising if ageing and fluid intellectual decline were not at least in part responsible for memory decline. However, this begs the question – what is the nature of the link?

It has been suggested that memory decline may in part be due to the selective physiological changes in the brains of ageing people, and that the decline in neural functioning is reflected in a concomitant decline in both fluid intelligence and memory. On a priori grounds, this is a reasonable assumption. The decline in both numbers and efficiency of neurons (see Chapter 1) means that the physical memory storage system is inevitably compromised, leading to the possibility that this will have psychological consequences (see Rosenzweig, 1996). For example, using PET
scans, Cabeza et al. (1997) and Madden et al. (1999) found significant differences in the patterns of activity in the brains of older and younger adults during memory

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tasks. This could be the product of different strategies using different areas of the brain rather than a physical decline. However, at a more fundamental level, animal studies of ageing rodents have demonstrated that older neurons often show a decline in efficiency in learning and memory tasks (e.g. Russell, 1996; Shen et al., 1997), and statistical modelling indicates that there is probably more neural noise in older human brains, interfering with accurate processing of signals (Allen et al., 1998). At a broader anatomical level, studies have related ageing memory decline to anatomical and functional changes in the frontal lobes (e.g. Haenninen et al., 1997; Purcell et al., 1998; Stuss et al., 1996) and the hippocampus (e.g. de Leon et al., 1997; Golomb et al., 1996). Decline in these areas can neatly explain many of the memory deficits experienced by older adults. Since the hippocampus, amongst its other roles, acts as a

‘relay station’ between STM and LTM, a deficit in its functioning will have particularly severe consequences. Likewise, a deficit in frontal lobe functioning may severely disrupt planning and ordering of memories.

Taking a slightly different approach, it can be observed that memory skills which do not decline are very much part of crystallised intelligence (knowledge of facts, procedures, and so forth). Problems tend to occur when participants have to process novel information and concurrently deal with other tasks (this is most clearly seen in working memory tasks). Thus, it is not surprising to find that such tasks are strongly correlated with fluid intelligence and general neural efficiency, as was noted above.

Similarly, Rabbitt (1988b) noted that scores on various tests of STM and LTM did not correlate with each other if intelligence test performance was partialled out. This indicates that declines in memory, like declines in intellectual performance, tend to occur in processes which are especially sensitive to the status of neural functions.

However, it is once again important not to assume automatically that these changes are inevitable or totally physically-based. For example, Rabbitt (1988b) is at pains to point out that not all of the memory decline can be attributed to changes in fluid intelligence (nor in participants’ choice reaction times, which were also measured).

Again, it is possible that at least in part, lack of practise of mental skills causes some neural systems to decline through disuse. Furthermore, general lifestyle may have serious consequences. For example, long-term stress elevates some hormone levels which may accentuate hippocampal atrophy (Bremner and Narayan, 1998).

Suggested reading

Baddeley (1983) provides an immensely readable introduction to the general psychology of memory, and the book is warmly recommended. Baddeley (1995) is a

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more advanced text, but is still reasonably accessible to a non-specialist. Good introductions to studies of ageing and memory are provided by Chapter 11 of Schaie and Willis (1991), Chapter 8 of Perlmutter and Hall (1992), Cohen (1996), Craik et al. (1995) and Rabbitt (1998). A discussion of the neurological aspects of memory change is provided by Woodruff-Pak (1997).

chapter 4

Ageing and Language

Introduction

The effect of ageing on linguistic skills is rarely given much consideration in general gerontological texts, beyond a cursory glance at changes in the physical characteristics of the voice and the decline in the ability to recall stories. This is a pity, because there is a considerable research literature on the subject – not as vast as that on ageing and memory or on dementia, perhaps, but nonetheless sufficient to merit more than a passing nod. ‘Language’ comprises not just speech production and comprehension, but also, of course, writing and reading. This chapter will concentrate on the last of these skills, because it is the one for which perhaps the best developed theories are available, and upon which most research has concentrated.

Introspectively, reading is perceived as being a fairly automatic and instantaneous process but in fact it involves the co-ordination of a variety of different skills, from the very basic to the very complex. On a priori grounds, normal reading must involve at the very least the following processes. First, there must be a mental mechanism for identifying individual letters, to distinguish them from, say, random splodges of ink, or items from a foreign alphabet. Furthermore, there must be a method of identifying whether sequence of letters form real words or whether they are merely nonsense strings (e.g. aslkdhf), and also of judging how to pronounce the word (i.e. of converting the printed into a spoken representation). Following from these stages must be a skill of judging if sequences of words form meaningful phrases. These have to be judged for both their syntactic and semantic acceptability. For example, the phrase: goldfish make suitable pets
is sensible, if banal. The phrase:

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hypotheses make sensible pets
is more interesting, but is obviously nonsense, and is said to be semantically unacceptable (loosely, semantics is the expression of meaning). However, the phrase’s syntax (loosely, its grammar) is acceptable. Conversely, a phrase such as: goldfish makes suitable pets
is syntactically unacceptable (because it is grammatically incorrect), but it could be argued that it still conveys a meaning, and thus is semantically acceptable. A final stage in the reading process must involve extracting meaning from the phrases.

Introspection shows that one does not remember every word of what has been read –
instead, one recalls the gist of the story. Thus, readers must possess a method of extracting the key features of a piece of text.

It must not be supposed that all the processing is in one direction from the basic skill of letter recognition to the relatively complex one of meaning extraction, since the latter operations can send information back down the processing chain to speed up reading. For example, suppose one is reading a passage of text written in an appallingly untidy hand, and suppose that some letters are completely unrecognisable, represented below by x s:

Ix is xoutful if anx moxe axxixtance is rexxired. Remxmbxr the xroverb: txo maxy coxks xpoil the xxxxh.

Most readers should have little difficulty in decoding this message. There are several reasons for this. First, some words like xoutful and xroverb can only be doubtful and proverb. Thus, the reader makes use of knowledge of which letter combinations make real words to work out what the indecipherable letters stand for. In other instances, semantic knowledge is used. For example, Ix alone could be If, It, In or Is. However, Ix is only makes sense if Ix is It. The final word of the passage ‘ xxxxh’ is unrecognisable by itself, but is easily recognised as broth because it is the last word of a well-known saying. This is an example of semantic facilitation, where the semantic content of a passage enables one to predict the words coming up. This does not just apply to reading sloppy handwriting. For normal print, one uses one’s expectations to facilitate word recognition, and it has been demonstrated that words which are logically linked to what has just been read are read faster than less predictable words. Thus, if one had been reading about animals, then one would read tiger faster than armchair. In formal experimental situations, the phenomenon is tested by presenting participants with a word or sentence (the ‘prime’) and then presenting them with a word which may or may not be semantically related to the prime.

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Participants are usually asked to decide if the word is a word or not, or to say the word out loud. In both instances, responses are faster if the prime is semantically related. How facilitation occurs is still hotly contested, but generally it appears that the mind in effect places mental representations of semantically related words on

‘standby’ so that if they appear in print, their meaning is accessed faster.

A final consideration is the role of memory. Obviously, without LTM (long term memory), it would be impossible to read a story and understand it, simply because one would keep forgetting the plot. Less obvious is the need for working memory (see Chapter 2, or the Glossary), but one must be able to keep in mind what has just been read, otherwise by the time one reaches the end of the sentence, one would have forgotten the point of it, and this would be especially true of long convoluted sentences such as this.

Thus, reading involves the active integration of a number of perceptual, cognitive, linguistic and memory skills. It will not have escaped some readers’ attention that the processes involved in the comprehension of spoken language are similar.

There must be the capacity for recognising individual letters or words; for identifying they are correctly pronounced; for identifying meaning and whether phrases are syntactically acceptable; and finally, for extracting the gist of a spoken message. Obviously, there are differences – reading is accessed visually, speech acoustically, so readers can (and do) look back at something they have not understood, whilst listeners usually have fewer opportunities to do an analogous thing, and ask a speaker to repeat something they have difficulty with. Speech and writing also have different conventions. Writing, for example, tends to be more formal and grammatically correct. Indeed, there is a considerable debate whether speech and writing share any processes in common (Olson, Torrance and Hildyard, 1985). In this chapter, the debate will not be addressed, but given that reading and listening have functionally analogous processes, examination of the effects of ageing on the two skills will be conducted in tandem, with reading examined first and then listening skills (where research evidence is available). It is not necessarily implied, however, that a change in a reading sub-skill is automatically linked to a change in the analogous listening sub-skill. It should also be noted that the effects of ageing on the skills of speech production and writing have received relatively little attention, but such experimental findings as there are will be placed at appropriate points in the commentary.

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The role of reading in older people’s lifestyles

Because reading is a sedentary activity, it is often assumed that older people spend more time engaged in it than younger people. In fact, some evidence points in the opposite direction (e.g. National Council on Aging, 1975). Despite worthy intentions, people generally do not read more once retirement presents the opportunity to do so through increased leisure time. Older adults who read a lot were almost invariably voracious readers when they were younger. If solely those older adults who are active readers are considered, then there are some intriguing differences between them and their younger counterparts. The older active readers spend more time reading (e.g. Rice, 1986a), but significantly more of this time is spent on reading newspapers and magazines (e.g. Ribovich and Erikson, 1980; Rice, 1986a). This means that the reading ‘practice’ older people obtain may be of a poorer quality, because the content of newspapers may be facile compared with the demands of, for example, a ‘heavyweight’ novel. In the same manner that failure to train strenuously reduces an athlete’s performance, so a failure to read sufficiently demanding texts may cause a decline in reading skills. Why this change in reading habits should occur is open to debate. Reduced mental resources may mean that some older people no longer have the intellectual rigour to plough through Dostoevsky et al. Alternatively, when old age is reached, many people may feel that they have read most of the fiction they wanted to read, and have no desire to reread works for which they already know the plot. A more cynical view is that older people feel that there is too little time left to waste it on wading through tedious ‘classics’. Younger adults may read ‘heavy’ works to ‘improve’ themselves. Older people may no longer have this competitive urge. For whatever reason, older people select ‘easy’ reading over 90
per cent of the time, be it periodicals, newspapers or ‘light’ fiction. Furthermore, they appear to get the same level of enjoyment out of reading as do younger adults (Bell, 1980; Rice, 1986a).

Physiological constraints

As was noted in Chapter 1, the eyesight of most older people worsens, and visual acuity (‘focusing power’) is reduced. One study (Bell, 1980) estimates that about 23
per cent of community resident older people are incapable of reading normal print. A solution to this problem is to print books in a larger typeface (for the technically minded, 18–20 point, which is about the size of the main chapter titles in this book).

Perhaps the best known example of this in the UK is the Ulverscroft series. The larger print makes easier reading for those with poor sight, but a study has shown that in

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the UK at least, there are disadvantages. The first arises from the fact that large print books have a relatively small market. Younger visually handicapped adults tend to use magnifying equipment, enabling them to cope with normally sized print.

Therefore, the principal market is older people. This is further restricted by the fact that few readers buy large print books – most borrow them from the local library.

These considerations mean that publishers tend to stick to fairly ‘safe’ lightweight fiction, which will appeal to the largest readership, such as that by James Herriot, Agatha Christie, Catherine Cookson, and so forth. Whilst there is nothing wrong with these authors per se, this policy means that an older person with eyesight problems is restricted in his or her choice to texts which are unlikely to stretch his or her reading abilities. An additional consideration is that many older people are limited in the amount they can read. Large print books are heavy, and older people may take fewer books home from the library than when they were younger, simply because they cannot carry more (Bell, 1980). Furthermore, there is some evidence that while large print size may increase the rate at which words can be read aloud, it may decrease the speed with which they are read silently (Bouma et al., 1982).

However, Lovie and Whittaker (1998) found limited evidence that print size had an effect on reading rate. As noted in Chapter 2, adjusting print size of intelligence tests lessened, but did not remove, age differences (Storandt and Futterman, 1982), whilst Rosenstein and Glickman (1994) found increased print size had no effect on performance of a personnel selection test. The font face used can also affect reading speed (Vanderplas and Vanderplas, 1980), although note that Cerella and Fozard (1984) found that making print harder to read did not differentially affect older people relative to younger people.

It should be noted that many older people are unaware that they have problems with their vision. Holland and Rabbitt (1989) noted that all participants from the age of 50 onwards gave near-identical subjective ratings of their vision, though in reality there was a marked deterioration in the older participants. A decline in perceptual abilities does not just mean that older people need larger print and/or hearing aids, however. A sensory loss can directly affect the efficiency with which information is processed. For example, Rabbitt (1989) noted that older people with mild hearing loss (35–50db) had great difficulty remembering lists of spoken words, even though they were earlier able to repeat them all perfectly as they were spoken to them. It appears that hearing impaired older people can perceive words, but it takes greater effort to do this, leaving fewer mental resources to encode and remember them. That there is nothing especially wrong with their memories can be shown by the fact that if the participants were shown printed lists of words, then there was no difference be-

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tween their and normal hearing controls’ performance (i.e. the effect was confined to when hearing was part of the processing chain). Schneider (1997) presents evidence that many of the ageing problems with speech perception may lie in relatively peripheral rather than cognitive processes, and demonstrates that, for example, cochlear degeneration and relatively small changes in the fidelity of signal transmission can have much broader effects on, for example, following conversations in a noisy environment or rapidly-spoken prose.

The voice also undergoes changes. The obvious superficial alterations, in a raising of pitch and a weakness of projection, arise from a variety of factors, including muscle wastage and a reduction in lung capacity. Other changes may result from relatively modern phenomena, such as (ill-fitting) dentures and smoking (Thompson, 1988).

This loss of vocal efficiency also shows itself in a slowing of articulation rate, for normal impromptu speech, reading a passage of prose, and reaction times to pronouncing words (e.g. Laver and Burke, 1993; Oyer and Deal, 1989; Ryan, 1972). However, it should also be noted that slower speech rate correlates significantly with memory span (Multhaup, Balota and Cowan, 1996) implying a cognitive connection as well.

Handwriting undergoes changes (see Miller, 1987) largely tied to physical deterioration. Aside from the effects of conditions such as the early stages of dementia (Slavin et al., 1999) and Parkinson’s disease (e.g. Contreras-Vidal, Teulings and Stelmach, 1995), ‘normal’ ageing too presents its problems. For example, fine control over the spatial co-ordination of finger and wrist movements involved in handwriting declines in later life (Contreras-Vidal, Teulings and Stalmach, 1998) and generally older writers are less efficient in using visual feedback (Slavin, Phillips and Bradshaw, 1996). However, not all age differences are necessarily due to physical factors. For example, it is worth noting that many older adults who are ‘naturally’

left-handed use their right (i.e. less efficient) hand for writing, simply because until relatively recently, many schools forced all children to write with their right hands (see Beukelaar and Kroonenberg, 1986). This may distort findings on some age differences in handwriting skill. The effects of these changes, other than in the aesthetic appearance of the writing itself, are mixed. Dixon, Kutzman and Friesen (1993) found that overall, writing speed decreases with age across a wide variety of writing tasks. However, to some extent this is shaped by the level of familiarity of the tasks: the more familiar the task, the less the age difference. In addition, the more tasks were practised, the less the age difference became (recalling Rabbitt’s findings on the effect of practice on reaction times reported in Chapter 2).

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Word recognition

There are a variety of ways to test the ability to read single words, but two of the commonest are the lexical decision and the naming latency tasks. The former requires participants simply to decide if a group of letters forms a word (note that the participants do not have to identify what the word ‘says’). A naming latency task measures how quickly a participant can read a word aloud. Generally, older people are no worse at these tasks than younger adults when the task is presented in its conventional form (e.g. Bowles and Poon, 1985; Cerella and Fozard, 1984).

However, if the tasks are made harder or more complex, then often an age decrement appears. For example, Bowles and Poon (1981) found this when participants were given a modified lexical decision task. Participants had to judge pairs of letter groupings, both of which had to form real words for a ‘yes’ response to be given.

Allen et al. (1993) manipulated the difficulty of the words used in a lexical decision task in ways likely to strike at relatively peripheral (such as altering the ease with which stimuli could be encoded) and relatively central (such as word frequency) aspects of processing. The researchers concluded that age differences tend to arise in peripheral rather than central mental processes (e.g. there were no age differences induced by word frequency). This is echoed in the findings of Madden (1992) who found age differences were greater when the visual appearance of the words (likely to be a fairly peripheral effect) was manipulated. Evidence of lack of differences at a central level is provided by amongst others Karayanidis et al. (1993), who found no differences between the EEG patterns of older and younger adults during a lexical decision task (though there were some differences when encountering words seen earlier, this is essentially a memory rather than word recognition effect). Generally, as task difficulty increases, then so does the size of the age difference. However, Myerson et al. (1997) demonstrated that this can be reduced to a Brinley plot – in other words, the general phenomenon may be explained in terms of the general slowing hypothesis (for further discussion, see Chapter 2).

In semantic facilitation experiments, older people are generally slower (as with many reaction time experiments – see Chapter 2). However, older participants gain a disproportionately greater advantage from this, when compared with recognising words seen in isolation (Laver and Burke, 1993; Myerson et al., 1992; though note that earlier commentators, such as Craik and Rabinowitz, 1984, found no difference). At one level the explanation for this phenomenon is simple – ‘a slow horse will save more time than a fast horse when the distance is reduced by a constant amount’

(Laver and Burke, 1993; p. 35). If one horse runs at 40 kilometres per hour, and another at 20 kph, then cutting the race distance from 40 to 20 kilometres will save 30

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minutes for the faster horse and an hour for the slower one. In a similar manner, if older people are reacting less quickly, then facilitation (which in effect decreases the computational ‘distance’) will be of greater benefit to older participants (see also Bennett and McEvoy, 1999).

Knowledge of pronunciation of words might also be expected to be preserved in later life, and indeed this would appear to be generally the case (though note that the speed with which words can be pronounced may decrease – see above). Typically, pronunciation is tested by presenting participants with a list of irregularly spelt words (e.g. yacht, dessert), and asking them to say them out loud. Because the words do not obey conventional spelling rules, their pronunciation cannot be calculated from first principles. For example, pronouncing dessert by conventional spelling rules would yield the spoken presentation of desert (and vice versa). Those readers who have already read Chapter 2 will appreciate that pronunciation abilities are therefore part and parcel of crystallised intelligence (loosely speaking, general knowledge), which is largely ageing-proof. It follows from this that pronunciation ability should remain stable in later life. Nelson and O’Connell (1978) examined the pronunciation abilities of 120 adults aged 20–70 years, and found no significant correlation between test score and chronological age (Nelson and McKenna, 1973). This word list was developed into the National Adult Reading Test, or NART. A subsequent study by Crawford et al. (1988) found a slight negative correlation between age and NART
score, but this disappeared when either length of education or social class was partialled out of the equation. Hence, concluded the authors, ‘age has little or no effect on NART performance’ (p. 182). Because of such arguments, the NART has become widely used as a quick assessor of crystallised intelligence, particularly where older participants with dementia or some other kinds of brain damage have retained the ability to read whilst being incapable of some other intellectual tasks (e.g. Brayne and Beardsall, 1990; Carswell et al., 1997; O’Carroll, Baikie and Whittick, 1987; O’Carroll and Gilleard, 1986; however, this is now disputed – see Chapter 6). The NART is not necessarily a totally accurate guide, however. When words from the NART are placed in the context of a sentence, then performance generally improves (Conway and O’Carroll, 1997, who developed this format into a new test – the Cambridge Contextual Reading Test (CCRT) – see Beardsall, 1998). In other instances, the NART may overestimate intelligence levels (Mockler, Riordan and Sharma, 1996), whilst researchers using an American version of the NART (called, not surprisingly, the American NART or AMNART or ANART) found somewhat different patterns of results within groups of White-American and African-American older people who were either non-demented or suffering from dementia (Boekamp, Strauss and Ad-

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ams, 1995). It is difficult to get a clear overall picture from these and similar studies simply because different samples of people have been used (e.g. some have dementia, some have not; amongst studies of dementia, different grading criteria have been used, and so forth). The general conclusion of many researchers is that the NART is a fair general predictor of intellectual status (and breakfast consumption: cereal eating and test score are positively correlated; Smith, 1998), even if the shortened (and quicker) format arguably lacks accuracy (Bucks et al. , 1996) and the full test is not absolutely precise (see Law and O’Carroll, 1998).

On a related topic, spelling skills in later life might be supposed to experience the same fate as word recognition. Knowledge of spelling rules is a crystallised skill, and as such should be relatively immune from ageing effects. However, there is evidence that this is not the case. MacKay, Abrams and Pedroza (1999) observed that older participants were as adept as younger participants at detecting misspellings in a list of words. However, there was an age difference in being able subsequently to retrieve the correctly and incorrectly spelt words from memory. MacKay and Abrams (1998) also found that misspellings increased in later life, as did Stuart-Hamilton and Rabbitt (1997). These age-related deficits are not directly attributable to general slowing, crystallised intelligence or education level. Stuart-Hamilton and Rabbitt found fluid intelligence to be a good predictor of spelling skills, whilst MacKay and co-researchers are (at the time of writing) developing an intriguing theory linking the decline to a more specific linguistic coding deficit (see MacKay, Abrams, and Pedroza, 1999). In part it is predicated on the transmission deficit hypothesis (MacKay and Burke, 1990) which argues that concepts are stored in interconnected

‘nodes’. Ageing weakens these connections and the ease with which nodes may be activated, though this can be compensated for by regular practice, and/or stimulation by more prompts. Hence, inter alia, new pieces of information are more prone to inefficient processing than older pieces, and recognition is easier than recall.

Syntactic processing

Relatively little research has been conducted on semantic or syntactic processing independent of the concurrent considerations of text recall. However, one notable exception is a series of excellent papers and articles by Susan Kemper on changes in syntactic processing in older people. Kemper (1986) requested younger and older adults to imitate sentences by creating new ones with the same syntactic structure.

She found that the older participants could only reliably imitate short sentences: long sentences, particularly those containing embedded clauses, were the hardest to

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imitate. Baum (1993) likewise found that increasing the syntactic complexity of sentences resulted in age group differences in a sentence repetition task; this also occurred when the sentences were used in a lexical decision task. Obler et al. (1991) found similar effects of syntax on sentence comprehension. This syntactic decline is also reflected in spontaneous everyday language. Kynette and Kemper (1986) noted that the diversity of syntactic structures declines with age, whilst there is an increase in errors such as the omission of articles and the use of incorrect tenses. In a similar vein, Kemper (1992) found that older and younger adults had the same number of sentence fragments in their spontaneous speech. However, the younger adults’

fragments tended to be of ‘better quality’, being false starts to statements, whereas older adults tended to produce these incomplete statements as ‘filler’ during a pause.

Kemper and Rash (1988) reported other examples of this decline. For example, the average number of syntactic clauses per sentence fell from 2.8 for 50–59-year-olds to 1.7 for 80–89-year-olds. The researchers also assessed the Yngve depth of the syntax. This is a fairly complex technique which gives a syntactic complexity ‘score’

to a phrase or sentence (the higher the score, the more sophisticated the construction). Yngve scores declined with age, but more intriguingly, they correlated well (r = 0.76) with digit span. Thus, the better the memory, the better the syntax. There is an attractively simple explanation for this finding. Syntactically complex sentences are almost invariably longer than simple ones, and to construct or comprehend them, greater demands are placed on memory. Or, put simply, more words have to be remembered at one time. This is a plausible explanation of why older people simplify their syntax – they know that their working memory no longer has its youthful capacity, so sentences are simplified and shortened to cope with this.

However, as Kemper herself has acknowledged, this is an over simplistic explanation. More probable is that declines in spans and syntax are both manifestations of a general intellectual decline.

Comparable results are reported by Gould and Dixon (1993). They asked younger and older married couples to describe a vacation they had taken together, and analysed their descriptions for linguistic content. The general finding was that the younger couple produces a greater amount of detail. The researchers attributed the older couples ‘failure’ to do this to a decline in working memory. However, they also acknowledge it is possible that the age-related change is due to a shift in attitude –

‘the younger couples ... May have given less consideration to being entertaining than did the older couples’ (Gould and Dixon, 1993; p. 15). Perhaps all those extra details were simply superfluous tedium. There is little more irritating than a person continuing to repeat the same point after it has already been made. The extra details, whilst

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perhaps showing off greater memory stores, also irritate when they hold up the flow of the narrative. Thus, they are superfluous. Related to Gould and Dixon’s findings is a study by Adams (1991), which noted that compared with a group of younger controls, older adults’ written summaries of stories tended to interpret the text at a more abstract level, and placed emphasis on a précis of the story’s structure. This qualitative difference may arise because of a loss of processing capacity. For example, if the older participants cannot remember as much about the story, then talking about it in abstract terms might be a wise option. Kemper and Anagnopoulos (1993) likewise argue that older people may use various discourse strategies to circumvent deficiencies or discrepancies in their syntactic processing skills. An alternative response is that the older people are deliberately using a different mode of thought, and Adams cites the emerging work on developmental models of change (see Chapter 2) as a possible theoretical framework by which to judge these changes.

Kemper (1987a and b) examined six diaries kept by people for most of their adult lifespans. Drawn from museum archives, the diaries commenced between 1856 and 1876, and finished between 1943 and 1957. Kemper found that the language used became simpler over the writers’ lifespans. Sentence length decreased, as did complexity of syntax. For example, the number of embedded clauses declined, and there was an increase in the failure of anaphoric reference (e.g. referring to ‘he’ without adequately specifying which of two previously cited males is meant). At the same time, the sophistication of the narrative declined, and increasingly events were described as a catalogue of facts rather than as a ‘story’ with a plot and a conclusion.

This decline cannot automatically be attributed to an intellectual failing. As anyone who has kept a diary for some time will know, writing it can be a chore. Thus, the older they got, the less motivated the writers may have felt to write a ‘story’ (or perhaps less happened in their lives which motivated them to describe it in flowing prose). Again, rereading their attempts at creative writing might have so embarrassed the writers that they decided to resort to a less florid style. It may also be the case that as the writers grew older, general attitudes to writing styles relaxed, and thus a simpler style was deliberately adopted (e.g. when the diaries began, the massive Victorian novel was in its heyday, and when they ended F. Scott Fitzgerald and Hemingway were contemporary figures). Indeed, Kemper (1987b) could identify a cohort difference even within her small sample. The writers born earliest in her group used significantly more infinitives (‘to go’, ‘to do’, etc) than did the younger ones.

Bromley (1991) gave participants aged 20–86 years the task of writing a description of themselves. Analysing the results, he found that the syntactic complexity and

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breadth of vocabulary exhibited in the writing was related to the participant’s age, but that other factors, such as word length and readability, were affected by the participant’s educational level and level of vocabulary (as measured by the ‘Mill Hill’

test, a common crystallised intelligence measure, see Chapter 2). Interestingly, fluid intelligence did not play a significant role. However, Bromley’s findings can be criticised in the same manner as Kemper’s – namely, it is possible that the changes represent a cohort difference or a deliberate change in writing style, especially since the changes do not appear to be heavily reliant on processing skills.

A related argument concerns how the changes in older people’s language can be linked to linguistic usage in childhood. In other words, do older people regress to a childlike linguistic state? This is known as the regression hypothesis. The argument, in a strong form, does not seem plausible, because the grammatical usage of older people is still far more sophisticated and varied than that of children (see Kemper, 1992). Although language may in some sense be simplified in later life, it does not simplify itself that much. At a weaker level, the theory is more plausible, since some linguistic usage may be superficially similar to children’s language, in that both use simplified forms, but this does not prove much beyond the fact that older people at times use simpler language (Hemingway used simpler language than Thomas Hardy, but nobody thought Hemingway had regressed). However, beyond general considerations such as this, it is difficult to make very firm statements.

The results may also reflect a worsening of working memory. Kemtes and Kemper (1997) found that processing of syntactically complex sentences was correlated with working memory performance both at the ‘on line’ level of reading the text and the ‘off line’ level of comprehending the text. From this, it is plausible to extrapolate and more broadly link syntactic change to alterations in the general intellect. However, there is also evidence that the effects are confounded by crystallised skills, cohort effects, and possibly a deliberate change in linguistic style (though whether this is a response to a lowered mental processing capacity is a moot point).

Story comprehension

Story comprehension has attracted more research than any other linguistic topic in gerontology. This is not surprising, because ultimately the efficacy of listening and reading must be judged by how much information can be absorbed and comprehended. Because of the large number of studies, it is perhaps most convenient to itemise this field of research.

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General aspects

The basic ‘story comprehension’ paradigm is simple – a participant listens to or reads a short passage of text (usually 3–400 words long) and then in one form or another either repeats back as much as possible, or is given a multiple-choice recognition test.

Most studies have shown that older people remember less (e.g. Byrd, 1985; Light and Anderson, 1985; and Petros et al., 1983 in cross-sectional studies; Zelinski and Burnight, 1997 and Zelinski and Stewart, 1998 in a longitudinal study) and may generalise more (e.g. Zelinski and Hyde, 1996). However, whilst this is a general finding, it is not a universal truth, and varying the types of experimental participants and/or test materials can have a crucial effect, as will be seen below.

Choice of participants

Some experimenters, using groups of ‘old’ participants with an average age in their sixties, have failed to find a younger-older age group difference (e.g. Mandel and Johnson, 1984). Age differences are only reliably found when the ‘old’ participants are in their mid seventies or older (Meyer, 1987). Another important consideration is the education level of the participants. Studies have sometimes found no age difference when older people with a high verbal ability (and hence high IQ/education level) have been used as participants (e.g. Taub, 1979). Thus, as has been noted in previous chapters, those with a well-preserved intellect can maintain a youthful level of performance. The findings of Rice and Meyer (1986) criticise this assumption, however. They found that the quantity of reading practice declined in later life, and tended to concentrate on simpler reading materials. Rice and Meyer, (1988) demonstrated that although quantity and quality of reading practice were important in determining level of text recall, chronological age per se and intelligence were still the best predictors. Holland and Rabbitt (1990) found that among a battery of measures, the best predictors were age, and fluid and crystallised intelligence scores, and Brebion, Smith and Ehrlich (1997) demonstrated a correlation with working memory capacity.

Cavanagh and Murphy (1986) noted that personality type and level of anxiety also significantly influenced level of text recall. Dixon and Hultsch (1983) also found that emotion levels affected the performance of older participants. These findings are reflected in a study by Riggs, Lachman and Wingfield (1997). They gave older participants the task of repeating back a spoken passage, which they could pause when and where they wanted. In other words, they could divide the task into segments they felt most comfortable working with. The researchers found that participants who felt that their intellectual status was principally beyond their control, set them-

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selves longer segments of speech than they could remember, and were less good at predicting their memory skills than participants who felt they did have principal control over their intellectual functioning.

It is also worth noting that there may also be a considerable cohort effect in many studies. Ratner et al. (1987) observe that many studies compare a group of younger adults recruited from students, with older adults recruited from a broader demographic base. The researchers found a group of non-student younger adults matched for verbal ability with a group of students and compared the two groups with a group of older people on a prose recall task. The students performed better than the other two groups (the non-student younger and older adults performed reasonably similarly to one another). This implies that a considerable part of the age difference in many studies of story recall and comprehension may be attributable to using younger participants who not only are different in age but also radically different in skill at memorising and interpreting text.

Choice of presentation of materials

The findings within this field have been mixed. Even an apparently simple procedure, such as examining prose comprehension following simplification of the text has met with nebulous results. For example, Walmsley, Scott and Lehrer (1981) found that simplifying a passage of prose improved comprehension when the simplification was done by the subjective opinion of experienced writers. However, more objective measures, such as simplifying according to a readability formula, had no significant effect on recall.

Cohen (1981) found that older people were significantly worse at recalling spoken than written materials, whilst for the younger participants there was no difference (Zacks et al., 1987). This is what would be predicted from Rabbitt’s (1990) findings on auditory versus visual recall of word lists reported above. Presumably the decline in hearing is in this instance more disadvantageous to the older people than is the decline in their sight. Attempts to manipulate the presentation of the story itself have met with variable results. Some alterations have no effect. For example, requiring participants to read aloud versus reading silently does not affect the quantity of information recalled (Taub and Kline, 1978), nor does giving people the choice of subject matter for the to-be-read text (Taub, Baker and Kline, 1982).

Varying the speed of presentation of the story has yielded mixed results. Where participants are free to read at their own speed, usually no age difference is reported, but there have been exceptions (Meyer, 1987). Participants can be forced to read text faster by setting time limits on how long they have to read a piece of text. Auditory

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presentation rate can be increased simply by the narrator speaking faster. Obviously, the faster the presentation rate, the faster one has to process information to comprehend it, and one would logically expect older participants to be disadvantaged. Indeed, there are several studies supporting this argument, but a sizeable minority have failed to find an age difference. Furthermore, Petros et al. (1983) found that when both presentation and semantic difficulty were varied, there was no appreciable disadvantage to older participants beyond that experienced by the younger participants. Conversely, Tun et al. (1992) found that older people were differentially disadvantaged when recalling quickly-spoken passages. However, this age difference was not affected by having to perform a concurrent task of picture recognition (in other words, the magnitude of the difference remained the same).

Stine, Wingfield and Poon, (1989) demonstrated a significant age difference in recall of spoken words when they were ‘jumbled up’ so they made no sense, and this difference increased the faster the rate at which the words were presented. However, the difference diminished when the words made syntactic sense (e.g. ‘bright deep go-rillas fructate omnivorously’), and disappeared for all but the very fastest presentation rate when the words formed conventional phrases (i.e. that made both syntactic and semantic sense). This implies that older people may be limited in processing the spoken output (e.g. through poorer hearing, a lowered capacity in working memory, and so forth), but that they can compensate for this by making greater use of the semantic facilitation provided by normal phraseology. But this is predicated on the false assumption that processing jumbled prose is the normal way in which speech comprehension takes place, and that participants make use of semantic and syntactic information only as extra help when it is needed. However, the unusual combinations are the syntactic and jumbled sentences. If older people do less well on these, it may be because they normally make greater use of semantic and syntactic facilitation, but it could also be because they cannot attune to a different (and artificial) manner of speech comprehension as well as the younger participants can. It has already been noted in this chapter and elsewhere in this book that older people are particularly disadvantaged on novel tasks, but given practice at them, the age difference diminishes. Thus, it is possible that extended practice at the jumbled conditions might lessen the age difference.

Because of these issues, probably the safest conclusion is that the issue of age and presentation rates is as yet unresolved, and it is very much an artefact of the experimental method used.

Some other manipulations of text have an effect. For example, Connelly, Hasher and Zacks, (1991) gave participants short passages of prose to read. Interspersed in

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the to-be-read prose were segments of distracting prose, printed in a different font, which the participants were told to ignore. Both younger and older participants read the passage more slowly and correctly answered fewer comprehension questions, but the older group were disproportionately disadvantaged. Again, Dywan and Murphy (1996) found that when sections of italicised to-be-ignored text were interleaved with to-be-read text, older adults were more likely to make false starts and read out bits of the italicised text (before correcting themselves), and were also more likely to miscomprehend the to-be-read text by erroneously incorporating information from the italicised text. However, when later tested, younger participants were better able to recognise words from the italicised text, in spite of apparently being better at ignoring it. This implies that the younger adults were better at shutting out responses to the text rather than not reading it. It also implies that there is a difference in the degree to which readers of different ages are able to control the early stages in the reading process. This is supported by the findings of Stine-Morrow, Loveless and Soederberg (1996) that in reading text for subsequent recall, younger readers place relatively greater emphasis on the immediate features of the text, whilst older readers put greater store in contextual information.

Generally, complexity increases the age difference. For example, Byrd (1985) found older people were impaired on straightforward recall of a passage of text, but to be disproportionately disadvantaged when asked to summarise it. In other words, when the passage had to be simultaneously remembered and processed, older people were at a severe disadvantage. Again, Hamm and Hasher (1992) found that older people had greater difficulty in drawing inferences from ambiguous stories in which the text began by implying one thing before finally resolving itself in a different direction from the one initially anticipated. They attributed the age-related decline to a lessening ability to process information in working memory (i.e. to keep the initial story ‘in mind’ whilst resolving the contradiction introduced at the end of the story).

Light and Albertson (1988) found that ability to draw inferences from sentences was only marred when the sentences were complex and/or concurrent processing of another task was required. Cohen and Faulkner (1984) demonstrated that older participants were especially disadvantaged at a recognition task when they had to integrate separate facts gleaned from the story to answer correctly. Smith et al. (1989) tested memory for prose of three types: ‘standard’ (self explanatory); ‘scrambled’ (sentences with no coherent links); and ‘interleaved’ (two or more stories alternating with each other sentence by sentence). The older and younger participants performed qualitatively the same for the standard and the scrambled texts. However, for the interleaved condition, the younger participants treated it qualitatively as they had done for the

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standard prose, and the older participants treated it qualitatively as they had done for the scrambled prose. In other words, the younger participants had sufficient processing capacity to untangle the interleaved prose and treat it as a standard text, whilst the older participants could not do this.

It is tempting to ascribe the above changes to a decline in the memory skills of older people. However, it should be noted that some researchers have found a poor correlation between text recall and other memory measures, such as digit span (Light and Anderson, 1985). Other, more linguistic factors may also contribute. For example, Kemper and Rash (1988), reviewing their own and others’ studies, found that the quantity of information recalled varied directly with the syntactic complexity of the to-be-remembered passage. Given the evidence on syntactic changes presented in the previous section, this is not a surprising finding. More remarkable perhaps is the contrast between the recall of details versus main points of the text. Another reported finding is that older participants remember as many main points of a story as younger adults, but that they are significantly worse at remembering details (Cohen, 1989).

For example, in remembering a story, an older person might remember that it involved a girl entering a shop and buying a dress, but he or she might not recall the colour of the purchase. A failure of memory for details is not surprising if one argues that they require more processing to be remembered, and thus are less likely to be memorised than the main points, which are modest in their processing requirements (Cohen, 1988; Holland and Rabbitt, 1990). However, as the next section will demonstrate, this phenomenon is not universally true.

Interaction between participant type and reading materials It might be supposed that if the prior experience of participants was relevant to the reading matter, then this might have an effect, but Morrow, Von Leiner and Altien (1992) did not find this to be the case. They tested groups of older and younger participants who were a mixture of airline pilots and non-pilots, on stories, some of which had a flying theme and some did not. There was a significant age difference in ability to recall items (specifically, participants were asked which character was being referred to as ‘he’ or ‘she’ in a sentence they had just read). However, level of flying experience had no effect on the age differences.

In an excellent review of the literature, Meyer (1987), drawing principally on work by Dixon et al. (1984), observes that age differences in recall of main points and details is not as clear-cut as some commentators have supposed. Instead, the main points-details balance seems to depend upon the (verbal) intelligence of the participants and the type of text being used. Normally, well-structured prose with a clear,

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logical text is used. When younger and older adults with high verbal abilities are tested on this sort of prose, then typically age differences are small or non-existent on main points but larger for details. However, for lower verbal ability people, the reverse is true – in other words, the age difference is on main points of the text rather than the details. This whole pattern is turned on its head when unstructured text is used (i.e. where there is no clear narrative thread to the story). In this instance, high verbal participants show an age difference on main points, and lower ability participants show an age difference on details. This is summarised in Table 4.1.

Table 4.1 Relative differences in recall of main points and details (adapted from Meyer, 1987)

Prose Type

Well Structured

Ill Structured

Level of

Higher verbal

Difference bigger

Difference bigger

Participants
ability
for details
for main points

Lower verbal

Difference bigger

Difference bigger
ability
for main points
for details

Two major explanations have been proposed to account for age declines in story recall. The first, introduced above, is that it is simply due to a decline in processing capacity. This can comfortably explain why in some instances main points are better remembered, because they are less demanding of mental resources. However, without modification, the theory cannot explain the qualitative differences in performance across types of text. The second explanation is that differences between higher and lower verbal ability participants are due to different reading strategies.

Thus, the lower ability participants have chosen a strategy which is diametrically opposed to that of the higher ability participants. However, this theory in its ‘strong’

form is difficult to defend, because it implies that lower ability participants go out of their way to choose the wrong strategy (Cohen, 1988). By combining elements of the capacity and strategy theories, however, it is possible to gain an insight into why age changes affect story recall in such an intriguing fashion.

The higher verbal ability participants will be considered first. Meyer (1987) plausibly argues that they are more likely than lower ability participants to be responsive to an author’s intentions. If someone writes a passage of prose with a relatively

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obscure plot, then it is probably the case that the author expects readers to pay more attention to details. An extreme example of this is a telephone directory, but more commonly, authors of many textbooks employ this strategy when wishing to impress the reader with the range of the topics being covered. Murder ‘whodunits’ provide another example where, to resolve the issue, the details must be attended to, and the plot, such as it is, is merely a device for accruing clues. Conversely, where there is a strong narrative thread to the story, the author clearly intends the reader to attend to this, with details intended to add a little local colour, and little else. It therefore follows that in well-structured prose, higher verbal ability participants attend primarily to the main points, and details are only processed for storage if there is any spare processing capacity left over after the main points have been gathered (please note that this is an analogy – the reader does not necessarily have conscious awareness of the process). Given that the processing capacity of older people is generally less than that of younger people, it follows that older participants will have less capacity for pick-ing up details. The finding by Stine and Wingfield (1988) that older and younger adults tend to have a similar pattern of recall of text when there is a low ‘density’ of information, and that the age difference widens the denser the information becomes, supports this argument. Conversely, in ill-structured prose, the details hog the attention, and it is main points which are processed only if there is spare processing capacity.

Hence, for higher ability participants, the points-details balance shifts according to what the participants think the author is stressing as more important. For lower ability participants, a different explanation is required, which hinges on the likelihood that they have relatively inefficient reading strategies. There is some evidence from child and adolescent readers that lower verbal abilities are associated with poor or ill-coordinated general reading strategies (e.g. Fredericksen, 1978; Stuart-Hamilton, 1986), and Hartley (1988) has provided some tentative evidence that this also applies to older people. Note that it is not being argued that poorer readers have chosen a strategy which is the reverse of better readers’ – only that they are less efficient. Lower ability participants, just like the higher ability participants, know to some degree that they must concentrate on the main points in a well-structured text, and on details in an ill-structured one. However, they are less efficient at searching out and encoding information, and thus do not take in their fill. This would appear to be a fairly profound deficit. As part of a larger study, Taub (1984) gave older participants a comprehension test in which the prose they had read was in front of them, with key passages and phrases underlined. The higher ability participants made use of this, but the lower ability participants did not.

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Because structured text places greater emphasis on main points, participants tend to notice more of them. The difference in the processing capacities of younger and older adults means that the former encode more of them than the latter. For ill-structured text, the reverse applies. An objection to this argument is that in terms of numbers, there may be an equal number of details and main points in well- and ill-structured texts. However, this ignores pragmatics (the understanding of intent as opposed to explicit meaning). Thus, simply counting the numbers of details and main points ignores their relative subjective importance.

The above arguments are perhaps made clearer by an analogy. Suppose that the lower and higher verbal participants are like riflemen on a shooting range. Targets appear, and the riflemen have a limited time in which to shoot as many targets as possible. In the same manner, readers have only a limited time in which to take in as much information as possible. Suppose that some targets are worth twice the points of others (in the same manner that main points and details can be more important than each other in different types of text). Higher ability readers are like good marksmen, who pick off the high value targets first, and then in the remaining time shoot at as many of the lesser value targets as possible. The older, skilled marksmen may be slower at shooting, and thus although in the time available they hit as many of the prime targets as younger shooters, they have less time for the remaining lesser targets. The higher ability readers behave in a similar manner – each gets roughly the same number of ‘important’ pieces of information, the difference only appearing in secondary factors. The lower ability readers are like poor shooters – they will aim at anything, and hit much less often than the good marksmen. However, the law of averages means that the more prominent targets will be hit more often by chance than the less prominent ones. In a similar manner, different types of text will cause some features to be more salient than others. The younger shots will hit more targets than will the older people, not because they are better at aiming, but simply because they can fire more shots in the time available.

Ecological validity

The above findings have to be weighed against the argument that the experiments reported above lack ecological validity (in other words, they are not very realistic).

The standard story recall test – of reading a passage of 3–400 words then attempting to regurgitate it whole – is hardly an everyday activity. Rice (1986b) observes that the only activity where anything approaching this skill is required is studying for exams, an activity which few older people indulge in. The experience is probably more central to the younger participants, thus creating an experimental bias.

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However, even in hardened exam takers, attempts at verbatim recall do not consist of attempting to learn 3–400 words in one reading. A far saner strategy would be to learn such a length of prose sentence by sentence (and evidence for age differences in this activity is more equivocal). In short, the text recall paradigm is unrealistic, and much of the age difference may be a cohort effect. Another consideration is the length of the prose passage used. Experimenters have usually chosen items of about the same length as magazine or newspaper articles – the commonest items read by older people (Rice, 1986b). However, they do not accord with other reading experiences. Meyer (1987) observes that a ‘very long text’ used in only a minority of studies is about 1600 words. Given that a moderately sized novel is circa 60,000
words, even the longest texts currently being used in standard experiments fall well short of a realistically long piece of prose. The reason for this observation is that, as librarians know to their cost, older adults are often appallingly bad not only at remembering the plots of books, but also which books they have read before. Clive James, the writer and television presenter, once worked as a librarian, and describes the phenomenon thus:

‘I ran out of answers for the little old ladies who wanted to know if they had already read the books they were thinking about taking out. The smart ones used personal-ised coding systems… There were hundreds of them at it all the time. If you picked up a book by Dorothy L. Sayers or Margery Allingham and flicked through it, you would see a kaleidoscope of dots, crosses, blobs, circles, swastikas, etc.’ (James, 1983; Ch. 8)

The phenomenon seems to be widespread. The author has spoken to a number of librarians who practically gave a paraphrase of Mr James’s observations. However, this shining failure of recall for lengthy passages of prose seems to have escaped researchers’ attention.

Summary

The study of language changes in older people is currently fragmented. Some areas have been covered in depth, whilst others have barely been touched upon (e.g. there is a woeful lack of studies of writing skills). Because of this, interpretations must be guarded.

It should first be noted that declines in sight and hearing will affect linguistic skills. More generally, a decline in physical health may generally lessen access to the

‘outside world’, and with it conversational opportunities, library visits, and so forth.

Within the home, reading habits change, with a general shift towards ‘lightweight’

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reading materials. Whether this is due to declining intellectual skills or changing motivation is a moot point, but nonetheless, for many older people there is an appreciable alteration in the practice of reading and other linguistic skills. This may in part account for the more general changes in language. However, the usual suspects of general slowing and intelligence must also be cited (though surprisingly, crystallised intelligence may not play a particularly major role). Concentrating on specific skills such as word recognition, syntactic processing and story recall, it can be seen that there are age-related declines. One study (Hale and Myerson, 1995) estimates that overall, older readers may be as much as 50 per cent slower than younger adults.

However, the magnitude of the age difference is probably inflated by experimental artefacts such as the types of test materials used, cohort effects, and so forth. Perhaps the biggest criticism is that many reading tests are unrealistic – people do not normally spend their time learning very short stories verbatim, pronouncing obscure words or deciding if a string of letters on a computer screen forms a word or not.

Thus, a loud note of caution needs to be sounded over these results, since the measures used probably do not directly match on to real life experiences.

Recommended reading

Light and Burke’s (1988) edited collection of papers on ageing linguistic skills is probably the most comprehensive review currently available (see reference for Hartley, 1988). However, there is a great deal of repetition between chapters, and many authors assume a detailed prior knowledge of technical terms. Kemper (1988, 1992) provides an excellent overview of her own work. For those interested in the general mechanics of reading, Ellis (1993) is recommended. Although outside the remit of this book, there is a useful sociolinguistic study of older people’s language by Coupland, Coupland and Giles (1991) which some readers may find of interest.

chapter 5

Ageing, Personality
and Lifestyle

Introduction

This chapter considers how older people present themselves to others. This will be principally examined by considering age-related changes in personality, but the related issue of the lifestyles which older people elect to follow will also be considered, as well as the attitudes people hold about ageing and older people.

‘Personality’ can be defined in many ways, but a useful general definition is:

‘the individual characteristics and ways of behaving that, in their organization or patterning, account for an individual’s unique adjustments, to his or her total environment’ (Hilgard, Atkinson and Atkinson, 1979)

Elsewhere in this book, the efficiency of the psychological skills under discussion can usually be gauged by a simple scale. For example, how many questions are correctly answered, how syntactically complex an utterance is, or how many list items are correctly recalled. Personality assessment is less clear-cut, since how can one judge what is a ‘good’ or a ‘bad’ personality? Obviously, people who behave like Mother Theresa or, conversely, Adolf Hitler, are easily categorised, but most people fall into a ‘grey area’ in between, and exhibit a mixture of attractive and quite unappealing behaviours. To complicate matters further, what is appealing to some is appalling to others. For example, someone who is the life and soul of the party to one group of people may be seen by another group as a loudmouthed airhead.

Accordingly, a single objective measure of personality ‘goodness’ is impossible to construct. The best one can hope for is to look for qualitative differences between the 137

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personalities of individuals, and, where possible, to measure these against ‘real life’

behaviours.

Because personality measurement is relatively resistant to objective measures, much work in this field is descriptive and resistant to abbreviation. The solution to this problem is either to devote an entire textbook to the subject or to present a general overview in the form of a thumbnail sketch. For obvious reasons, the latter solution is adopted here. However, the reader should be aware that behind many of the apparently simplistic arguments presented lie often sophisticated theories and descriptions (for more detailed discussions, Turner and Helms, 1994; and Pratt and Norris, 1994 are particularly recommended). A further reason for erring on the side of brevity is that much of ageing personality and lifestyle research draws heavily on work in other areas (particularly sociology) and thus falls outside the ambit of this book.

Trait models

Perhaps the area of personality research with the strongest links to mainstream psychology is the study of the personality trait. This may be defined as an enduring characteristic of a person’s personality which is hypothesised to underpin his or her behaviour. The concept sounds complicated, but in fact it is often used in everyday life. For example, if one is told that a person is ‘very nervous’ then one can predict how he or she will behave when watching a horror film (in other words, one assumes that the trait of ‘nervousness’ will cause that person to display a characteristic behaviour pattern). A number of trait models, which seek to explain behaviour by means of a few disposing factors, have been developed by psychologists. Perhaps the best known is Eysenck’s measure of extraversion-introversion, neuroticism and psychoticism. Eysenck argued that people’s personalities are principally determined by the degree to which they display these three traits. The extraversion-introversion (E) trait measures the degree to which a person is outgoing and assertive. Someone who tends towards these characteristics is said to be an extravert, and the stronger they possess the attributes, the more extraverted they are said to be. Conversely, someone who is shy and retiring is an introvert, and again, the more shy and retiring they are, the more introverted they are. Eysenck argued that the extraversion-introversion measure is a continuum: people are never purely extraverted or purely introverted. Instead, they possess features of both attributes, although overall they tend to be one kind or the other. For example, a person who is extravert and can go to a karaoake bar without the slightest worry (even when sober)

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may nonetheless be racked with embarrassment in using a public changing room.

The psychoticism (P) trait is a measure of the degree to which a person is emotionally

‘cold’ and antisocial, and the neuroticism (N) trait gauges the extent to which a person is anxious and emotionally unstable. High scores on the P and N scales do not necessarily mean that a person is mentally disturbed, but rather that under stress, they are likely to display psychotic or neurotic characteristics. Eysenck measured the E, P
and N traits using the Eysenck Personality Questionnaire (EPQ). Participants are asked to give ‘yes’ or ‘no’ answers to a series of statements designed to elicit how strongly individuals identify with each particular trait. For example, one of the questions designed to assess the strength of extravert tendencies is ‘Are you a talkative person?’ (Eaves, Eysenck and Martin, 1989; Appendix B).

E, P and N alter as people get older, and gender also has an important influence. P
declines with age, but the rate of decline is much greater for men than women. At 16
years, male P scores are almost double those of females, but by the age of 70, this difference is practically non-existent. More curious is the change in E. Both men and women become more introverted as they get older. Males in their late teens are more extraverted than females, but thereafter, their extraversion declines at a much greater rate, so that by their sixties, males are more introverted than females (the crossover point, where the two sexes are equally introverted, occurs in the forties). The changes in N are less spectacular. There is a decline in neuroticism for both sexes, but at all ages, female scores remain higher than male scores (Eysenck, 1987; Eysenck and Eysenck, 1985). Eysenck (1987) argues these findings predict that older people should be less prone to violent swings of mood and hence calmer. Note that Eysenck was not arguing that older people should necessarily be happier in later life. If anything, people should become more indifferent about the world, with only relatively small swings in mood in either direction. At an ideal best, such indifference might be cultivated into calmness and serenity, but equally, an undesirable apathy or sloth might be produced. Eysenck argued that personality changes across the lifespan are primarily the result of physiological changes altering levels of excitation with the nervous system. This argument is disputed by many other psychologists and a plausible case can be made for changes in lifestyle being the prime causes of shifts in E, P
and N. For example, older people may become more introverted, not because of changing levels of neural excitation, but because, as they age, society becomes less geared to their needs. This causes older people to withdraw in upon themselves, and this in turn engenders feelings of reserve and hence increased introversion. Because men , more than women, define themselves by their role in society (see below), men

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will show a disproportionately bigger loss of assertiveness as they age, reflected in their declining E score.

The argument for an influence of lifestyle on personality change receives guarded support from other trait studies. Kogan (1990) reviewed a number of longitudinal studies of changes in personality traits across the lifespan. His general finding was that in many instances there were significant shifts in personality which were com-mensurate with changing lifestyles (e.g. the transition from college to paid employment). However, he also found that generally there was less change in the latter half of adult life (note also that as for IQ, individuals maintain the same general position relative to their age peers – it is the raw scores on measures which change). Other researchers have found even less change. Butcher et al. (1991) found no appreciable changes in the pattern of personality using another common measure of personality (the Minnesota Multiphasic Personality Inventory (MMPI)), and generally, longitudinal studies of self-reported personality measures have found little alteration, even though participants often feel they have changed dramatically (Perlmutter and Hall, 1992). Kogan concludes that discrepancies between studies may reflect different tests and methods of analysis.

Although it cannot be judged that one personality type is necessarily more worthy than another, there is evidence that some personality types may be more advantageous in particular situations. For example, Jerram and Coleman (1999) analysed the health behaviour of older adults using the Big Five personality model. This is predicated, as its name implies, on the assumption that personality is best described using five basic personality traits – conscientiousness (how reliable a person is), agreeableness (how compliant with others’ wishes) and openness (how willing to cope with the unfamiliar), extraversion, and neuroticism (see Stuart-Hamilton, 1999a for further discussion). Jerram and Coleman found that people possessing a higher level of openness, agreeableness, extraversion and conscientiousness and lower levels of neuroticism had fewer health problems and generally led healthier lifestyles. Other studies have tended to support this finding. For example, Lauver and Johnson (1997) demonstrated that higher levels of neuroticism may be disadvantageous in coping with chronic pain in later life, whilst Spiro et al. (1995), reporting on a longitudinal study, found it to be correlated with high blood pressure. Generally, neuroticism has been found to be adversely related to general health status in older people (Kempen, Jelicic and Ormel, 1997). Again, a higher level of extraversion appears to be advantageous in recovering from a stroke (Elmstahl, Sommer and Hagberg, 1996) and more generally in maintaining a high level of morale (Adkins, Martin and Poon, 1996) and feeling of well-being (Francis and Bolger, 1997). However, it should be noted that

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there is some danger of a chicken and egg problem with the above research. The issue will be returned to later in this chapter, but it must be remembered that whilst a person may have better health or quality of life because of their personality, equally, their personality could have shifted in response to their changing health and quality of life.

Psychoanalytic theory and the ageing personality

Some of the earliest attempts to codify the ageing personality came from psychoanalysis. It is difficult to give a concise definition of this term. However, in its usual sense, it means any treatment regime which is based upon an integrated theory of the subconscious and its effects on behaviour. Often these theories are named after their author (e.g. ‘Freudian’ after Sigmund Freud, ‘Jungian’ after Carl Jung). Strictly speaking, psychoanalysis is not part of mainstream psychology (see Stuart-Hamilton, 1999a), and many psychologists have questioned its efficacy (e.g.

Eysenck, 1952). However, from an historical viewpoint at least, a brief examination is necessary. The founding father of psychoanalysis, Sigmund Freud, was sceptical about the value of therapy being administered to older patients, because they had relatively little remaining life in which to enjoy the benefits of treatment (generally, the treatment of older people has been a minority subject within the psychoanalytic literature, though this position is changing, see Gorusch, 1998; Settlage, 1996). The crux of Freud’s theory is that personality is made up of a mixture of three components

– the id, ego, and superego. The id describes basic appetitive urges, the ego people’s rational selves, and the superego a set of moral dictums (often unrealistically harsh).

For reasons too complex to describe here, Freudian theorists felt that the id’s efficiency and strength were drawn from the state of a person’s smooth (i.e.

involuntary) muscle, whilst the ego’s strength is dependent on the state of the central nervous system (CNS). Because the CNS declines more rapidly in later life than does smooth muscle, the ego becomes relatively weaker than the id. A tenet of Freudian theory is that the ego strives to keep the id in check. To prevent the id getting the upper hand, the ego starts to conserve its energy by rationalising resources. In psychoanalytic terms, this means adopting a relatively unvarying and conservative set of attitudes and responses, even though they may not be entirely appropriate to the situations older people find themselves in. This perceived inflexibility of older people is specious, however. For example, Pratt et al. (1991) found no age differences on measures of moral reasoning, and as shall be seen below, the ageing personality varies greatly across individuals (in other words, there is no

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single typical ‘older personality’). It is worth noting that, although he did little formal work on ageing, in his private life and correspondence, Freud appears to have had a very melancholy and illogical attitude towards ageing (Woodward, 1991).

Erikson (1963; 1982; see also Wolf, 1997) felt that personality developed throughout the lifespan – unlike other psychoanalysts, who felt that it was essentially determined by childhood habits. He argued that at different ages different conflicts had to be resolved. For example, in infancy, individuals must resolve the conflicting impulses to trust or to mistrust by developing a sense of trust. There are eight of these conflicts to resolve, of which only the final one occurs in later life. The goal of this stage is ego integration: the acceptance that earlier goals have been satisfied or resolved, and there are no ‘loose ends’. A person who feels that not everything has been achieved can feel a sense of despair because, with death approaching, it is too late to make amends. Thus, the despairing individual also comes to fear death, and he or she ends life feeling anxious and depressed. Hannah et al. (1996) present evidence that ego integration is usually only attained by people who have successfully resolved the earlier Eriksonian stages of conflict. In other words, personality in later life is as much a product of early behaviour as the current situation. A criticism of Erikson’s theory might be that, taken simplistically, it portrays ageing as a passive preparation for death. However, this is not what Erikson intended. He viewed the final stage of development as a learning process, and in ‘such final consolidation, death loses its sting’ (Erikson, 1963; p. 268).

Peck (1968) expanded on Erikson’s theory, and argued that in later life, three conflicts need to be resolved. The first of these is ego differentiation versus work-role preoccupation. Many working people (particularly men) establish their status and self concept through their work. Thus, a professional person may develop a high self-esteem simply because they have an occupation which society regards favourably. However, when a person retires, this status disappears with the job. Thus, retirees must find something in themselves which makes them unique or worthy of an esteem previously conferred on them by a job title. The second conflict is body transcendence versus body preoccupation. For most individuals, ageing brings a decline in health and general physical status. If an older person overemphasises bodily well-being in extracting enjoyment from life, then disappointment will almost inevitably result. Successful ageing involves an ability to overcome physical discomfort, or at least finding enjoyable activities where bodily status is unimportant. The third of Peck’s conflicts is ego transcendence versus ego preoccupation. This essentially means that a person comes to terms with the fact that he or she will inevitably die.

This is obviously an unpleasant thought, but Peck argues that, by attempting to pro-

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vide for those left after a person has died, and continually striving to improve the surroundings and well-being of loved ones, being over concerned for the self and the self’s fate can be overcome.

Levinson’s view of ageing is akin to Erikson’s and Peck’s but concentrates rather more on the role of the older person in family and society (e.g. Levinson, 1980).

Changing physical and occupational status means that in the early to mid-sixties (the late adult transition), people must come to terms with the fact that they are no longer the prime movers in either work or in family life (this may be affected by lowering of typical retirement age, see Settersen, 1998). To remain content, older people must therefore learn to shed leadership and take a back seat (other researchers have reported similar conflicts, e.g. Settersen and Haegestad, 1996). This does not mean that all cares and duties can be avoided, since aside from assuming the role of wise coun-sellor to family and younger friends, older people must come to terms with their past (in a manner similar to that described by Erikson). Levinson refers to this process as the ‘view from the bridge’.

Do these theoretical personality types really exist outside the confines of a psy-chotherapist’s office? Reichard, Livson and Peterson (1962) interviewed 87 American men aged 55–84, half of them in retirement, and half in full- or part-time employment (note that for some jobs in the USA there is no compulsory retirement age). Many points raised by Reichard et al. support the psychoanalytic theories. For example, participants approaching retirement seemed to be particularly ‘on edge’

and self-deprecatory, indicating that the period in question was perceived as being one of change and anxiety. Overall, five main personality types were identified. Constructiveness is akin to the optimal resolution envisaged by Erikson’s and Peck’s theories – people possessing this trait had come to terms with their lives, and were relatively free from worries, while striving to interact with others. The dependent or

‘rocking chair’ type created some contentment, but individuals were dissatisfied with products of their own efforts, and relied on others to help or serve them, regarding later life as a time of leisure. The defensiveness or ‘armoured approach’ type is essentially neurotic. Participants possessing it carried on working or were engaged in a high level of activity as if to ‘prove’ that they were healthy and did not need other people’s help. The fourth type: hostility, involves blaming others for personal misfortune. Participants unrealistically attributed failures throughout their lives to factors other than themselves. In part this sprang from a failure to plan adequately. The final type identified by Reichard et al. was self-hatred. The self-hating individuals were akin to the hostile type possessors, except that they turned their hatred and resentment inwards. Reichard et al. found that people possessing the first three types

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were well adjusted towards later life, whilst those possessing one of the latter two were less successful. However, given that the researchers’ personality descriptions contain implicit value judgements of quality of lifestyle, this is not surprising.

Other personality type studies

Reichard et al. also observed that people’s personalities had developed long before the onset of later life. In other words, the types are not the result of ‘being old’ per se. It follows from this that, in order to enjoy later life, one must prepare for it. This argument is somewhat supported by the findings of a longitudinal study reported by Haan (1972). Participants were studied from their teens to the onset of middle age.

Various personality types were identified, but these can be principally divided into: the stable and secure; those akin to Reichard et al.’s defensive personalities; and the insecure who blamed others for their misfortunes and who often had disorganised lifestyles. These types are remarkably similar to those found in studies of older people, and it is reasonable to conclude that those found in later life are probably those which have been there since early adulthood (Kermis, 1986). However, this may not be entirely true. In a review of the literature, Aiken (1989) notes that while some of the more stable personality types may not alter greatly over the lifespan, the less stable types may be more labile in response to age changes. Again, it can be shown that older people become more inward looking (Neugarten, 1977). This is not necessarily surprising. Unstable personalities might be expected to change, and stable people may always have been stable because circumstances have always been consistent and relatively rewarding. Older people may become inward looking, not because of an intrinsic compulsion, but because the death of friends and a world which caters primarily for younger people leaves few attractions for previously outward-going older people.

It is interesting to note that some personality types may be better adapted to early rather than late adulthood and vice versa. Type A personalities are very hard-edged, competitive types who find it difficult to relax – in Eighties parlance, they are ideal

‘yuppie’ material. Type B personalities are the opposite – easy going, carefree, and so forth. It might be expected that Type As will be best suited to early adulthood when there are perhaps the greatest chances to exhibit competitiveness in career chasing, sport, and so forth. Later life should not suit Type As because of its emphasis on a sedentary lifestyle. For Type Bs, the reverse should hold true. Strube et al. (1985) measured the psychological well-being of a group of people aged 18-89, and found that in general Type A and B personalities fulfilled this prediction, although the

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results were mediated by factors such as the social environments of individuals.

Again, Shimonaka, Nakazato and Homma (1996) found Type B personalities to be more prevalent amongst centenarians.

Returning to studies of the measurement of personality types within older people, Neugarten, Haringhurts and Tobin, (1961; 1968) studied a sample of people in their seventies. Four principal personality types (with subdivisions) were identified, which bore great similarity to the traits uncovered by other studies already mentioned. The most desirable type was the integrated personality. People in this category were either: reorganisers (as one activity became physically impossible, another was found); focused (activities were limited to a small set of feasible and highly rewarding ones); or they were disengaged (the deliberate abnegation of many responsibilities). Another major type was the armoured-defensive personality. People in this category were either holding on types who felt that they could stave off decay by maintaining a high level of activity; or they were constricted, and dwelt on what they had lost as a result of ageing. The armoured-defensive individuals were less satisfied than those with integrated personalities. A third group possessed passive-dependent personalities. Like Reichard et al.’s dependent/’rocking chair’

types, such people relied on others to help them (the succourant seeking), or they withdrew from interaction with others as much as possible (the apathetic). The fourth and final group comprised the disorganised personalities. These unfortunate people had serious problems (possibly early dementia?) and could not be classified as functioning conventionally.

As has been noted, there is much similarity between the various type studies. All emphasise that personality is largely fixed long before the first grey hairs appear, and that essentially, older people can adjust their personalities but not alter them radically. There is more than one way to age successfully, but all essentially involve accepting limitations and renouncing responsibilities without suffering a feeling of loss. A slightly less successful strategy is to maintain a fear of the ravages of ageing, and to fight them by keeping as active as possible. However, as this involves a failure to come to terms with ageing, it is ultimately less satisfying. The worst option is to have no strategy at all and to blame all the wrong factors for one’s present state. Many commentators have arrived at the same general conclusions (e.g. Aiken, 1989; Kermis, 1983; 1986; Turner and Helms, 1987; Whitbourne, 1987). However, the argument presented is a generalisation and a potentially misleading one. Successful ageing involves accepting limitations and abnegating responsibility, but this may be because of societal pressure to hand over the reins of power. Accepting this change willingly may be akin to surrendering gracefully to a stronger opponent on the prin-

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ciple that if one is going to lose, one may as well do so with the minimum of hurt. In other words, the ‘successfully’ aged older person has not gained a philosophical insight as much as grasped a point of pragmatics. Another important consideration is socio-economic class. The ‘unsuccessful’ aged person may rant and rave about external forces precisely because their social position has yielded them fewer privileges and ‘lucky breaks’ (often researchers note that such individuals are downwardly socially mobile). In contrast, someone who has known ‘all the glittering prizes The cars, the hotels, the service, the boisterous bed’ (Auden, 1979) will be more likely to have a relaxed view of life. Accordingly, the older personality may be as much a product of social and economic circumstances as of any internally motivating factors.

This consideration does not refute the theories described, but one should be careful not to consider personality as a purely internally-driven entity.

Another approach to the above argument is to question whether ‘losing’

independence is necessarily such as bad thing. Cordingly and Webb (1997) note that the whole issue is imbued with major questions of status in many societies (particularly western ones) where individualism and ‘standing on one’s own feet’ is a key measure of societal approval. Older people are seen as being dependent and as such their status is diminished. Societal forces, though well-meaning, tend to emphasise the role of dependent older people and play down the idea of older independence. For example, Baltes and Wahl (1996) make the telling point that older people’s requests or needs for help (which of course help define their role as dependent) tend to be met, whilst independent behaviour is ignored. Baltes (1996) examined the issue of dependency in detail and argued that it can be both good and bad, depending upon the type of dependency and the circumstances in which it is acquired. Bad dependency might result from bad motives. Thus, an institutional environment in which older residents are denied any autonomy is a clear example of this. However, bad dependency can also be produced from good intentions. For example, a social worker might provide an older person not just with the specific help they need, but swamp them with lots of other forms of assistance (even though the older person has neither asked for them nor needs them), because they are seen as a generous aid package. Of course at one level they are, but this largesse is also forcing an older person to become dependent on a system to a much greater extent than they need. However, not all dependency is bad. Baltes notes that increased dependency can be good, if, for example, it liberates an older person from trivial cares or tasks which are too problematic. It should also be noted that bad dependency can be reversed or at least lessened through intervention. Thus, dependency is in itself neither good nor bad – it is how and why it is used which matters. Some researchers

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have found that increased dependency is predictive of subsequent illness (e.g. Willis et al., 1997), but the degree to which this is ‘good’ or ‘bad’ dependency is often uncertain.

It will not have escaped the reader’s attention that some researchers have argued for the relative stability of personality across the lifespan, whilst others have argued that it changes. There are several possible explanations for this. The first is that it is due to differences in measurement techniques (Kogan, 1990). This is plausible, but it hardly bodes well for research if a factor as important as personality can behave so ca-priciously when measured. However, it is worth noting that many longitudinal studies have only found personality changes when the participants are compared over several decades – relatively short periods do not yield large changes. Also, there may be a cohort effect – older participants may be less ‘open’ about their responses than younger people, not because of their personalities per se., but because they wish to be

‘polite’ (Stokes, 1992). A further factor is that different studies have measured different aspects of personality. This is a psychological facet which cannot be measured on a single scale as intelligence can be gauged by the IQ measure. Which of a wide range of measures are taken as representative of the personality and at what level (e.g. traits versus types) may lie behind many of the discrepancies between studies. Personality testing has been criticised for being inexact (e.g. Davis, 1987), and hoping to find reliable ageing changes when the measures are in such dispute may be a forlorn task.

Images of ageing and life satisfaction in later life General changes

It follows from the caveat given above that, to understand personality in later life, external forces impinging on older people’s self-image and life satisfaction must also be considered. A general consideration is the effect of the stereotype of the ‘typical’

older person. As was noted in Chapter 1, society expects people to behave appropriately for their age. Kite, Deauz and Miele, (1993) found that stereotypes of older people are stronger than those of gender differences, and that the archetypal

‘masculine’ attributes are felt to be particularly prone to decline in later life. Because the terms ‘old’ and ‘elderly’ are usually derogatory in western culture, it is small surprise to discover that in one study, only 20 per cent of people in their sixties and 51 per cent of people in their seventies labelled themselves as being ‘old’ (Ward, 1984). The author of this study also notes that, ironically, older people are often hoisted by their own petard, since when they were younger they formed the illogical stereotypes of ageing, which now haunt them. Stereotyping seems to affect older

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people’s confidence and generally, the more older people believe in stereotypes, the lower their self-esteem (Ward, 1977). However, given that many older people are likely to be more inward-looking, might it not be the case that they come to think that everyone of their age is like themselves, and thus the lower their opinion of others, the lower their self-regard? Again, perhaps self-image and stereotypes are self-reinforcing, creating a vicious circle. The exact relationship remains unclear, but for whatever reason, most studies find that self-image declines in later life in most people (Aiken, 1989). This is reinforced by a study by Ryff (1991). She asked younger, middle-aged and older adults to rate their past, present and future selves and well-being. She found that the younger and middle-aged adults tended to see themselves on a path of self-improvement – they were better than their past selves, and in the future would get even better. The older participants, on the other hand, saw the best behind them and a decline in front of them. Graham and Baker (1989) examined two groups of (Canadian) participants: a group of older people (mean age 67 years) and a group of younger adult students. Participants were asked to grade imaginary people of different ages (e.g. ‘40-year-old-man’) for their level of status within society. The researchers found that, for both groups of participants, children were graded at a low level, status then rose through the teens, twenties and thirties, and then began to decline once again, so that 80-year-olds were perceived to have roughly the same status as five-year-olds. However, although older participants gave the same relative balance of judgements as the students, the difference between the highest and lowest ratings was significantly less. Thus, although different generations have the same general pattern in their view of ageing and status, older people are apparently ‘slightly more egalitarian than the young’ (Graham and Baker, 1989; p. 255).

The above studies paint a bleak picture of ageing, both for older people’s images of themselves and younger people’s images of older people. However, it must not be assumed that such views are irrevocably fixed. For example, Guo, Erber and Szuchman (1999) demonstrated that exposing participants to positive reports about ageing can improve subsequent judgements of older people’s skills. Similarly, Stuart-Hamilton (2000) found that altering a set of five questions at the beginning of a questionnaire on attitudes from neutral to very slightly negative (the latter questions drew attention to the financial problems of some UK pensioners) was sufficient to create a significantly more negative set of judgements about older people in the latter group. The ease with which views can be manipulated implies that to some extent negative views of ageing may be a product of experimental design. Certainly in the studies which have found strongly negative views of ageing, participants have been

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asked to more or less make a direct comparison between an older and a younger person (Stuart-Hamilton, 2000). Under such circumstances, older people will be almost inevitably regarded in a negative light. It is not being ageist to say that on average, older people have more physical and psychological problems than younger people, any more than it is sexist to say that on average, women are shorter than men. However, such statements can easily predispose a person to ageist or sexist views. Thus, if participants are asked to compare younger versus older adults, the older adults will almost certainly come off the worse. This is indicated by Stuart-Hamilton (1998), who conducted a (UK) nationwide survey of women’s attitudes to ageing. Women of all ages were questioned, and were simply asked what they thought of older people on their own terms (in other words, without comparisons being drawn with younger adults). The responses were much more positive about ageing than those in many other studies. Therefore, at least some of the negative view of ageing is probably a result of how the questions have been asked.

Allowing for these criticisms, anti-ageing stereotypes are still strong. It has been argued that this is to some extent a product of particular cultures, and Japan has been cited by some commentators as a very pro-ageing society. To some extent this is true.

For example, Levy (1999) reports that Japanese people tend to have less negative attitudes towards older people than do Chinese or Americans. However, note that the view of ageing was still negative – it was merely the strength of the view’s expression which differed. Again, ageing stereotypes appear even when views are not directly measured by questionnaire. For example, Hummert, Garstka and Shaner (1997) found that participants attributed significantly fewer positive attributes to pictures of older people (there is also an interesting rebuttal of Graham and Baker’s claims of egalitarianism cited above, since photos of very old people were rated significantly less positively by older participants). Again, participants giving instructions to people of different ages tended to ‘talk down’ to older people, and although this was done less if it was emphasised that the older person was ‘competent’, nonetheless, speech was still different from when providing instructions to a younger adult (Thimm, Rademacher and Kruse, 1998).

Causes of change in image

Physical changes, from the relatively minor (e.g. greying hair) to the more serious (e.g. arthritis) can all cause a revaluation of self-concepts (Ward, 1984). Some studies have found that health and concomitant changes in mobility are the biggest predictors of satisfaction in later life, but others have failed to replicate this (e.g.

Bowling, Farquhar and Grundy, 1996) and findings may depend upon what

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measures the health gauge is weighed against. A range of treatments, from cosmetics to medical intervention can often alleviate at least some of the physical problems, but other changes – in societal roles and relationships – are irrevocable. Of these, some are chronic whilst others are significant single events. Of the latter, probably the biggest are retirement from full-time employment, and widowhood.

Work and retirement

Herzog et al. (1991) studied older adults who were working or were in semi-retirement. They found that well-being was not related to how much work they did as whether the work was what they wanted to do. This finding was the same for a group of slightly younger workers (aged 55–64 years). It is important to note that with changing employment patterns, retirement is no longer synonymous with ‘old age’ in the cut and dried way it perhaps once was. For example, Settersen (1998) found that for many people age is now an irrelevant criterion on which to judge retirement. With regard to retirement, it has been noted that people approaching retirement tend to be more apprehensive and self-deprecatory, but in most instances, once people have stopped working, the experience is pleasurable. However, there are some instances of people suffering psychological problems because they no longer feel useful. For example, Swan, Dame and Carmelli, (1991) reported in their study of American retired persons that those who felt that they had been ‘forced’ to retire had generally lower levels of well-being, and (perhaps not surprisingly) that people with Type A personalities were more likely to complain that they had retired against their will. However, it is difficult to exclude the possibility that such people would have suffered problems and complained in any case. Sharpley (1997) identified three factors – missing work, health, and relationships – and once again, it is tempting to argue that the latter two problems might have arisen regardless of retirement. For the majority, retirement brings little change in life satisfaction. However, other factors may impinge on this. For example, in couples with traditional gender roles, marital satisfaction is higher where the husband is working and the wife is retired than in the reverse situation (Myers and Booth, 1996; Szinovacz, 1996). Perhaps not surprisingly, marital satisfaction can be improved by retirement from a stressful occupation, but health problems may cause a worsening (Myers and Booth, 1996).

Again, there is generally an increase in satisfaction among very healthy retirees (Parnes, 1981). White collar workers tend to enjoy retirement more than blue collar workers, but this can probably be attributed to better health and finances (Bengston and Treas, 1980; Ward, 1984). The full picture may thus be complicated by

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individual differences and circumstances, and a fully comprehensive view has arguably yet to be created (Moen, 1996).

Widowhood

The state of widowhood (loss of one’s partner of either gender) more commonly affects women than men, because of the differing life expectancies of the two sexes.

There is some evidence that the impact of the loss depends upon how anticipated it was. For example, Eisdorfer and Wilkie (1977) found that the loss was less stressful if the deceased had been ill for some time (see also Wells and Kendig, 1997). In addition, older people tend to have a milder reaction than younger adults (Cook and Oltjenbruns, 1989), because older people are better primed to accept the death of a partner. In the majority of cases, adjustment to loss is reported as being at least satisfactory, though there are some residual signs of grief and other negative feelings 30 months after the bereavement (Thompson et al., 1991), and a sizeable proportion (20 per cent) of widowed persons report a failure to cope adequately (Lopata, 1973).

Furthermore, the number of negative aspects of personal relationships within the widows’ social circle has been found to increase in the years following bereavement (Morgan, Neal and Carder, 1997). Carey (1979) noted that men are better able to adjust than women. This may be because in traditional sex(ist) roles, a married woman’s status is determined by the presence of her husband, while the reverse does not apply as strongly. Also, a widowed man is likely to be financially more secure, and may have greater opportunities to find another partner. Other studies, however, have contradicted this viewpoint (Cook and Oltjenbruns, 1989), possibly because more men than women are inept at looking after themselves, and also because widowhood is primarily a woman’s experience. Thus, on the available evidence, the question of which gender suffers the more cannot be settled. Perhaps in any case the current social revaluation of gender roles may eradicate whatever differences there are.

Other factors

Although retirement and widowhood are the two principal acute factors influencing self-image and life satisfaction, other, often chronic factors take their toll, and monetary worries figure large in most researcher’s lists. Krause, Jay and Liang, (1991) demonstrated that financial problems (common in many older people) are a prime factor in reducing feelings of self-worth and in increasing depressive symptoms. This is true of many cultures. Krause et al.’s study found the same basic phenomenon in samples of both American and Japanese older people. Zhang et al. (1997) found financial problems to be a major negative factor amongst older people in China.

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Ferraro and Su (1999) similarly found financial problems increased psychological distress in participants from three different cultures (Fijian, Korean and Philippino, though note that Malaysian participants were an exception). However, the authors also noted that the level of social and family support can at least ease some of these problems. This is reflected in the findings of a longitudinal study by Russell and Catrona (1991), who found that the less the social support the older person experienced at the start of the study, the higher his or her depressive symptoms were one year later (and the greater his or her experience of ‘daily hassles’). Again, personality factors may play an important role. For example, a well-integrated individual can cope with stress far better than someone who is disorganised.

Conversely, a person in bad health and with poor finances may be better able to cope with the declines of health and wealth because they are already used to it (Ward, 1977; 1984). It is also worth noting that in addition to personality types, other psychological factors such as intellectual changes can dent self-esteem. For example, in Chapter 3 it was noted that a high self-report of memory lapses is correlated with level of depression. Perlmutter et al. (1987) note that this may create a vicious circle –
an older person who perceives his or her performance on a memory task to be poor may suffer a lowering of morale, which may further hamper his or her abilities.

It is also important to note that episodes in a person’s past can impinge on their attitudes to later life. Obviously, decisions about careers, relationships, whether to have children, and so forth, have a direct impact. Stallings et al. (1997) found that negative events in a person’s life tend to affect the negative aspects of the mood of a person and positive events the positive aspects with minimal crossover influences (supporting the so-called two-factor theory of well-being). Taking a different approach, Caspi and Elder (1986) examined feelings of life satisfaction in a group of older women who in their thirties had experienced the American Great Depression.

Middle class women who endured hardship at this time now had demonstrably higher ratings of life satisfaction as a result. However, the reverse applied to working class women in the same situation – they had a lower life satisfaction. Perhaps this is because the middle class women had demonstrably ‘won through’ to a better material lifestyle, while the working class women perceived themselves as being still ‘at the bottom’. In an analogous manner, people rated as high in wisdom, who experienced the Great Depression, had better psychological health in later life than people rated low in wisdom (Ardelt, 1998).

Other factors also may contribute to life satisfaction. For example, Cook (1998) found that participating in organised group reminiscence sessions improved the level of life satisfaction amongst older women in a residential home. This should not be

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taken as support for the stereotype that older people long to live in the past. Although there is evidence that at least some groups of older people would like their past achievements and status to be recognised more (Ghusn et al., 1996), when asked the question ‘looking back, what period of your life brought you the most satisfaction?’ the commonest response from older people was ‘right now’ (Field, 1997).

Generally, and perhaps unsurprisingly, social activities and friendships have been found to be beneficial by almost all researchers. An interesting twist on this is provided by Greenwood (1999), who found that where there are problems in a changing social life in later years, men are less likely to report decreased satisfaction, because in general they may have lower expectations of interpersonal relations than women. Again, it is not sufficient to group older people together and expect satisfaction to increase as a result. For example, in a telling phrase, Kovach and Robinson (1996) reported that being given a roommate in a residential home ‘predicted life satisfaction only for those who talked to their room-mates’ (p. 627). Participation in exercise activities or non-energetic leisure activities also is correlated with greater life satisfaction (and health). The authors of one study (Menec and Chipperfield, 1997) attribute this to an enhanced feeling of being in control of events (see also McConatha et al., 1998). However, although sociable activities are undoubtedly beneficial, pastimes do not necessarily have to be gregarious to enhance life satisfaction. For example, Sherer (1996) demonstrated that being allowed access to personal computers had a beneficial effect on the self-esteem and life satisfaction of older nursing home residents and day patients (it is perhaps worth noting in passing that the women in the study tended to use educational software, whilst the men played video games). Generally speaking, purposeful activity is beneficial to life satisfaction (Madigan, Mise and Maynard, 1996).

The above findings suggest that a rich tapestry of factors determine later life satisfaction. In part, this may be because many studies have an air of ‘seek and ye shall find’ about them. By asking a limited set of questions or focusing on a narrow range, then some factors can be made to appear more important than they perhaps are. For example, using a more qualitative interview technique, Glass and Jolly (1997) found that their sample of participants did not raise good health or finance as key factors contributing to life satisfaction. Not all studies are equally ‘guilty’ of this selectivity, but it is difficult to move beyond a fairly general statement that intuitively obvious factors, such as health, finance, bereavement, and retirement, have some influence on both self-esteem and general life satisfaction but these are undoubtedly not the only factors, and all of these may interact with each other and be mediated by personality

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variables. Unfortunately, this statement is not far removed from what a non-psychologist might produce if asked for an intuitive summary of the issue.

Personality and health

It is important to note that one aspect of personality is how one chooses to live, and this includes choices of diet, exercise, smoking, and so forth. The link between smoking and reduced life expectancy and the (more tenuous) relationship between diet, exercise and health are too well-known to need reiterating here. It should be noted, however, that people rarely take up ‘bad habits’ in later life (e.g. older smokers have usually been abusing their bodies for several decades) and accordingly, unhealthy lifestyles are not just a problem of later life (though Quinn et al. , 1997 note that poor eating habits tend to increase with age and are exacerbated by lowered finances and being male). It might be supposed that older people would find it harder to change their habits than younger people but in fact the two age groups respond to health education equally well (see Elias, Elias and Elias, (1990) for further discussion). Another important caveat is exercise – undoubtedly peak physical performance declines with age, and this is more pronounced for activities requiring sudden bursts of energy (e.g. athletics throwing events) than for activities requiring lower, but sustained, levels of energy (e.g. middle- and long-distance running).

However, several (though not all) studies have found that older people who follow an exercise regime have faster reaction times and better psychomotor performance (Spirduso and MacRae, 1990). This is not surprising, but of greater interest is that well-exercised older people’s performances would put many people in their twenties to shame (see the excellent review by Spirduso and MacRae, 1990, for further details). Thus, if an older person chooses to, they can considerably improve their life expectancy and physical and (in part) psychological well-being.

Considering a more direct relationship between personality and health, there appears to be a positive link between mental health and physical well-being. Studies have found a high correlation when people’s self-reports are considered, and a somewhat weaker correlation when objective measures of physical health are taken (Whitbourne, 1987). Whether physical well-being actually causes a person to feel content, or vice versa, is open to debate. Kermis (1986) raises the point that depression and/or stress can cause a worsening of health (e.g. by suppressing the immune system). Taking the reverse direction, it is clear on a priori grounds that physical disability can have a bad effect on a person’s psychological state. However, an important caveat needs to be raised. Maas and Kuypers (1974) observed that many illnesses of

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later life are preceded by related physical complaints earlier in life. This means that in many instances if there is a change in personality in response to illness, it may not just be the illness in later life which is causing this, it could be an effect accumulated across the lifespan.

Following from this argument, one can raise the hypothesis that physical and mental changes can exacerbate each other, forming a vicious circle. However, the links between illness and personality can be exaggerated. For example, the Type A personality has been associated with a significantly higher heart attack rate. However, a review by Elias et al. (1990) observes that whilst this may be true for younger people, having a Type A personality after the age of 65 does not increase the risk of coronary problems (the finding cannot be simply attributed to most people with Type A dying before they reach this age). Again, older people are often unaware or dismissive of their physical health (Costa and McCrae, 1985), indicating that the link between illness and self-image may be less clear-cut than first supposed.

A related topic is that of hostility and ageing. Hostility has already been mentioned above as a personality type, but it can also be defined as ‘a negative orientation toward others that has cognitive, affective and behavioral manifestations’ (Barefoot, 1992). Some studies have reported higher levels of hostility amongst younger adults and older elderly people, with a drop in hostility between these two ages (see Barefoot et al., 1993). This may in part be adaptive, because a healthy cynicism is arguably a useful tool for both younger adults first finding their way in the world, and older people in increased dependence on health and social welfare services. Comijs et al.

(1999) found that hostility was also associated with being mistreated. However, as many commentators have argued, it can also be disadvantageous, because high hostility levels are associated with an increased risk of heart disease (see Meesters, Muris and Backus, 1996) and other illnesses (see Ranchor et al., 1997).

Marriage

Generally, older married couples are found to be as happy or even more content than younger married adults (Cunningham and Brookbank, 1988). This may in part be due to reduced work and parenting responsibilities (Orbuch et al., 1996). Levenson, Cartensen and Gottman, (1993) assessed younger (40–50 years) and older (60–70
years) married couples on a variety of measures. They found that the older couples displayed greater equanimity of aims and sources of pleasure (and fewer sources of disagreement) and also tended to have more equal standards of health. Their results are encouraging, in that it would appear that older married people are not simply

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clinging to the wreckage because the prospect of living apart is financially and/or emotionally too awful to contemplate. In another sense, the results are uninformative, because they do not indicate whether happily married older couples have always been happily married or whether today’s happiness is the result ‘of a process in which old wars are diminished’ (Levenson et al., 1993, p. 312) to the point where a truce has been called. As the authors acknowledge, their ‘preliminary snapshot’ (p. 312) calls out for a fuller longitudinal study.

Sexuality and ageing

It is a commonplace observation that the media portray sex as being for the young and slim, and ageist humour dictates that older people wanting a sex life are either

‘dirty old men’ or ugly and desperate. Even those older people whom the media have labelled ‘sexy’ are chosen because, generally, they do not ‘look their age’.

Accordingly, older people do not receive support from everyday sources that wanting a sex life at any age in adulthood is normal and healthy. It is therefore little surprise to find that people’s professed interest in sex decreases after the age of 50 (Segraves and Segraves, 1995) and in part this is attributed to negative societal views (though illnesses and medical treatments affecting sex drive are also major contributors).

There are a variety of problems associated with studying sexuality in the later years. One is a cohort effect – older people were brought up in less permissive times, and are not accustomed (and indeed may lack the vocabulary) to talk about sexual issues. Surveying the history of studies of sexual activity in later life, Gibson (1992) observes that the more recent the study, the more often older people admit to having sexual relations. Non-compliance is a traditional problem with sex surveys (conversely, participants who are rather too willing to participate may also provide biased data). Therefore, older groups may provide less information, not because they have sex less often, but because they are less willing to talk about it. Another problem often cited by researchers concerns what constitutes ‘sex’. If penetrative intercourse is taken as the only measure of sex, then older people may show a greater decline in activity than if a wider range of activities is considered. It is worth noting, however, that sexually active older people generally report great satisfaction in whatever activity they indulge in (Matthias et al., 1997; Skoog, 1996). A further problem is one of opportunity. Since women on average live longer than men, there are a lot more older women than men. Thus, older women’s opportunities for heterosexual contact are diminished, and activity may cease not because of lack of capability or willing, but because of lack of a suitable partner. For men, the biggest problems are usually inability

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to sustain an erection and/or lacking the physical stamina for intercourse. Extrapolating from Gibson (1992), between 10 and 20 per cent of older men and 35 per cent (or more) of older women have no sex life (though note that figures vary enormously across studies). A final problem to be mentioned here is the relative under-treatment by health professionals, who may undervalue or ignore older people’s sexuality (Gussaroff, 1998; Mayers and McBride, 1998); generally, a high proportion of cases of sexual dysfunction in older adults remains untreated (Godschalk, Sison and Mulligan, 1997).

Generally, in addition to limitations of physical health, the level of sexual activity is dependent upon the level of activity in early adulthood (e.g. Martin, 1981). This implies that, once again, the state of one’s later life is determined by one’s earlier behaviour. However, it is worth remembering that sexual drives differ markedly between individuals (e.g. Masters and Johnson, 1966), and it is wrong to assume that there is a ‘correct’ level of activity, or indeed, that sexual activity is necessary at all, for successful ageing to occur.

Preferences for lifestyle

So far, the older personality has been conceived principally in terms of changes within the individual. In this and the following section, attention is turned to the question of how older people choose to interact with others. It has been tacitly acknowledged in various parts of the research literature that part of ageing is a preparation for death.

Nowhere is this made more explicit than in the disengagement theory by Cumming and Henry (1961). This argued that as people get older, their contact with the world lessens. At one level this is through a decline in the senses. At a social level, the loss of spouses and friends, and other social estrangements such as retirement, cause older people to disengage from contact with others. This was seen by Cumming and Henry as a rational process, initiated by older people and aided and abetted by societal conventions. It is as if older people are preparing to die by shedding their links with the physical world. The theory can be criticised (and indeed was) for presenting the behaviour of passively waiting for the ‘Grim Reaper’

as a good role model for older people. This is perhaps being a little harsh on Cumming and Henry, who were talking about relative rather than total disengagement. Later evidence indicated that disengagement was largely confined to individuals who were always reclusive (e.g. Maddox, 1970b). In other words, the phenomenon may be a ‘natural’ extension of a particular personality type, not a universal feature of ageing. Another criticism is that disengagement is a very rare

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phenomenon in many developing countries, where older people are kept in an active role in the community (e.g. Merriman, 1984).

Subsequent researchers argued that the best policy for older people is to keep as active as possible. Their argument is roughly as follows. Older people usually want to keep active, and life satisfaction is found to be greatest in those with an active involvement (see above). People who disengage from society have probably been doing so for most of their lives, in other words, it is not purely a response to ageing (Maddox, 1970a). In its extreme form, this activity theory is as unattractive as the argument it tried to replace. The image of hordes of social workers forcing older people to mix with others ‘for their own good’, with compulsory whist drives and so forth, is not a pleasant one. The modern consensus is that disengagement and activity theories describe the optimal strategies for some but not all older individuals, and which is better depends on a variety of factors, such as: financial circumstances (e.g. can one afford an active lifesytle?); health (e.g. does one still have the vigour for some hob-bies?); and personality types (e.g. introverts may hate an active lifestyle). It is also worth noting that a number of studies have found that increased social involvement only appreciably improves well-being in lower income groups (Caspi and Elder, 1986; Larson, 1978).

The role of the family

Many people, given the choice, would probably like to combine aspects of the disengagement and activity lifestyles. This is shown in research on preferences for family relationships. It would appear that in western nations at least, older people prefer to live independently, but also to have their children or close relatives living nearby. In about 80 per cent of cases, older parents live within 30 minutes’ travel of at least one of their offspring (Bengston and Treas, 1980). Thus, older people seem to like to combine the opportunity for activity through interaction with family members with disengagement through the privacy of their own homes. The family can have distinct advantages. For example, as has been seen in the studies of financial problems cited above, the effects of hardship can be at least partly offset by family factors (e.g. Ferraro and Su, 1999; Zhang et al., 1997). However, family members can be a more ambiguous asset in times of an acute rather than chronic problem. In a masterly review of the literature, Bengston and Treas observed that while family members were the usual and preferred source of comfort and help in a crisis, older people were more depressed the greater their expectations of assistance from their relatives. In other words, expect too much, and disappointment will almost inevitably

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follow (though note that the proportion of older people with unrealistically high expectations is relatively low). This is further supported by a study by Bengston and Kuypers (1986), who found that when a crisis occurs and help is needed, this may damage familial relations, because family members may feel that they have not adequately coped.

A detailed analysis of family intervention is provided by McCubbin and Patterson’s (1982) double ABCX model, where A is the event causing the crisis, B the familial resources for coping, C the familial perception of the crisis and X the perceived stress. Variations in A,B, and C will determine the overall level of stress the family and older person experience (see Clark, 1999 for an example of an application of the model). Gatz, Bengston and Blum (1990) created a similar model, comprising a sequence of event-stressor-appraisals-mediators-outcomes. The event is the crisis, and the stressor the deleterious effect of the event. Appraisals refers to the process whereby the family caregivers decide the degree to which they feel they can control the situation, and the mediators are the available aid and caring skills. The outcomes process refers to the degree to which the family feel stressed and/or adapted to the change in the situation.

Both these models of family care in a crisis are essentially descriptive, and there is a considerable research literature available to describe each stage of either model. The tone of this is rather uniform – most aspects of caring and adaptation are potentially stressful and have negative effects. Detailed reviews are provided by Gatz et al. (1990) and Wenger (1990). A caveat to these observations is that the majority of caregiving duties fall on the spouses or offspring of older people (Qureshi and Walker, 1989) –
thus, most caregivers are themselves older or middle-aged. Accordingly, caregivers themselves may experience physical problems in nursing sick patients, and increased incidences of ill-health in caregivers have (unsurprisingly) been reported (see Gatz et al., 1990).

As was noted in Chapter 1, in westernised nations at least, the proportion of the population aged over 60 has risen dramatically over the past hundred years. At the same time, for a variety of reasons the birth rate has dropped. This means that older people today have fewer relatives to seek support from than did older people in the historical past (though about 80 per cent of older people have at least one living son or daughter; see also Johnson and Troll, 1996). However, does this mean that the older person’s plight (if there is one) has worsened? The answer is probably not. First, because the general improvement in living standards and pension schemes means that older people can be self-sufficient more often than their ancestors could. The workhouse, the refuge of working class older people, no longer looms like the dire

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punishment it did only a few decades ago. It is also worth observing that the extended family (where three generations live under the same roof) was the exception rather than the rule in pre-twentieth century Europe (e.g. Laslett, 1976). In short, there has not been a ‘golden age’ in the past where greater pastoral care was given to older people.

It is also important to note that findings on the role of familial support can vary according to the social class of the family. For example, Sundstrom’s (1986) Swedish study notes that the geographical distance between older adults and their offspring is typically greater in the middle- than in the working-classes (although when this is controlled for, there is little class difference in level of care). This is perhaps accounted for by the finding from Qureshi and Walker’s (1989) English study that members of ‘higher’ social classes tended to use the phone and postal services more frequently. Other class differences are perhaps due to material opportunity rather than motivation. For example, Qureshi and Walker also found that ‘higher’ social class older people were more likely to visit other members of their families. However, measures of level of emotional closeness between family members were roughly the same across all social classes.

Cross-cultural differences in ageing

Societies differ in their attitudes to older people, and the study of this topic is known as ethnogerontology. The traditional division between East and West has often been commented on. Generally in the Far East, later life is revered to a greater extent than in the West (though there are signs of some change towards Western values, see Ingersoll-Dayton and Saengtienchai, 1999). Tangential to this, in general, relatively

‘primitive’ non-industrialised societies have a higher regard for later life, according it a special status. This may be because later life is relatively rare in such groups, and in peoples lacking a written language system, older people may be especially valued for their memories of the past. However, the very elderly and physically and mentally infirm are often regarded far less favourably (see Perlmutter and Hall, 1992).

Within industrialised nations, ethnic minority groups tend to have a higher proportion of multigenerational households, and closer-knit families (for majority culture Europeans, the social support systems in different countries are broadly similar (Wenger, 1997). In addition, for some ethnic minorities (e.g. African-Americans) the church may play a greater role in providing social support (Jackson, Antonvicci and Gibson, 1990). However, it is dangerous to overgeneralise such arguments, and confounding factors, such as the fact that ethnic minorities tend to have a lower

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socio-economic standing, are difficult to tease apart (see Rosenthal (1986) for a discussion of the methodological implications of ethnicity research).

Notwithstanding these comments, older people within an ethnic minority face what has been termed the double jeopardy - the problem that not only will they be treated prejudicially because they are older, but also because of their ethnic identity.

It is certainly true that older people from ethnic minorities under-use health and social care programmes (e.g. Gallagher-Thompson et al., 1997). Norman (1985) states the case more strongly, and argues that many older members of ethnic minorities are in fact faced with a triple jeopardy because, in addition to the afore-mentioned problems, they also, through the prejudice of others and often through communication problems, cannot get the help they need and deserve from the local or state authorities (other commentators such as Paz and Aleman, 1998, have identified the three factors as age, poverty and ethnicity, but the import of the term is the same).

Norman makes a strong case based on the practical problems faced by older ethnic minorities in claiming services and amenities. However, other measures, such as well-being and living conditions provide more equivocal support (see Perlmutter and Hall, 1992). This is not surprising, since many of the effects of the host country will be ameliorated by the practices of the minority community to which the older people belong. It should also be noted that some health authorities (though alas not all) are making demonstrable efforts to encompass the needs of minority older groups (e.g.

Hart et al., 1996; Tennstedt, Chang and Delgado, 1998). Finally, it is very important to bear in mind that in discussing ethnic minority groups (as with any groups) that there will be considerable individual differences within the group (see Whitfield and Baker-Thomas, 1999), and discussions of ethnic minority problems are descriptive, not prescriptive.

Summary

The findings of research on personality and lifestyle are varied. Studies of personality types and traits indicate that older people usually ‘receive’ their personalities in early adulthood, and any shifts thereafter tend to be a diminution of strength relative to younger adults. Certainly, there is not a personality type unique to later life. On the other hand, some types of personality enable people to cope with later life better than others. The identification of these comes primarily from psychoanalysis rather than mainstream psychology, but there is considerable empirical support for them.

However, all these arguments must be weighed against the considerable criticisms of personality testing and research methodologies. Again, it should be noted that many

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personality taxonomies incorporate implicit value judgements. For example, a successfully ageing person is held to have a placid and almost stoic attitude towards life. However, this conforms to the stereotype that older adults should be quiet wisdom-dispensing archetypal grandparent figures. Or in other words, people who make little fuss and make themselves available to others. This may be pragmatically the best way to grow old, but it is not the only way.

Having acknowledged that personality traits are largely born in early adulthood, and that some traits are more appropriate than others, older people still have a number of methods at their disposal for improving their lot, such as adopting a healthier lifestyle. The relationship between lifestyle and well-being is more complicated than it may first appear, however. Socio-economic class, ethnicity, widowhood, familial relations, finances, and many other factors interact to provide a complex web of events and pressures whose effects are far from fully mapped.

Recommended reading

Perlmutter and Hall (1992) provide excellent additional commentaries on many of the topics covered in this chapter (see particularly Chapter 16 on American ethnic minorities). An overview of personality research in general is provided by Stuart-Hamilton (1999a). The general issues of social factors in ageing are well addressed by Pratt and Norris (1994). Turner and Helms (1994) provide a useful overview of general adult development, and are particularly strong on discussions of personality and social development in later life. A more detailed discussion of the level of dependency exhibited by older people is an excellent book by the late Margaret Baltes (Baltes, 1996). Gibson (1992) provides an intelligent overview of sexual and emotional changes (see also Schlesinger, 1996). Although death and dying are not covered in this book, it is perhaps worth noting at this point two useful books on thanatology; for those interested – Kubler-Ross (1970) is rightly acknowledged as a classic (see also Kubler-Ross, 1997); and Stroebe, Stroebe and Hansson (1993) provides a more recent overview.

chapter 6

Mental Illness and Ageing

Introduction

Older people are less likely to suffer from mental illness than any other age group (Smyer and Qualls, 1999). All conditions, other than cognitive impairment, are at a lower level. This does not of course mean that mental illness in later life can be dismissed. It is a serious problem at any age, but in older people, may be compounded by generally poorer health and lowered intellectual skills. The number of chronic conditions an average person suffers from increases over the lifespan, and the problem is greater the lower the socio-economic group being considered (House et al., 1992). When further problems, such as double jeopardy (see Chapter 5), and declining intellect and memory are added into the equation, it can be appreciated that the problems facing older adults with mental illness may be considerable. Not surprisingly, there is a considerable literature on mental health in later life (see e.g.

Murphy and Alexopoulos, 1995; Parks, Zec and Wilson, 1993; Smyer and Qualls, 1999; Woods, 1996, for more detailed discussions). In the present chapter, an overview will be presented of some of the key features. We will begin with discussion of an illness which although not unique to later life, is certainly most commonly found in older people; namely, dementia. This will occupy a large proportion of the chapter. A final section will introduce the reader to some of the key concepts and findings in studies of older patients suffering from mental illnesses of other causes.

Dementia

Introduction

Dementia describes the global deterioration of intellectual functioning resulting from atrophy of the central nervous system. Although many people (and not a few 163

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textbooks) have the impression that the disease has only a few causes, in fact at least 50 have been identified (Haase, 1977), although admittedly a lot of these are extremely rare. It is also not true that dementia is synonymous with later life. This is wrong on two counts: first, a minority of older adults develop dementing symptoms, and second, dementia can be contracted at any age. It is the probability of developing the illness which increases with age. A useful rule of thumb by White et al. (1986) states that the incidence of dementia starts at 1 per cent at age 60, then doubles every five years (i.e. 2 per cent at 65, 4 at 70, 8 at 75, 16 at 80, 32 at 85). After the mid-eighties, the chances of contracting the illness decline; there is a lengthy discussion about this (see e.g. Hestad, Ellersten and Klove, 1998), but essentially it is reducible to ‘if you don’t catch it by then, then you probably never will’. This roughly concurs with the figures of other researchers (e.g. see Smyer and Qualls, 1999). It is also worth bearing in mind that many individuals will only show relatively mild symptoms, and, cold comfort as this is, they will probably die from other causes before the disease has gained a firm hold. This means that only 2–3 per cent of older adults are institutionalised because of dementing symptoms (Kermis, 1983). In other words, although these are noteworthy figures, developing dementia is not an inevitable feature of later life.

However, although an individual older person’s fears of becoming ‘senile’ are unrealistic, this does not mean that dementia is not a serious problem. From a demographic viewpoint, the illness poses a challenge to industrialised nations. As was noted in Chapter 1, both the actual number of older people and the proportion they form of the total population are increasing. This means that the number of cases of dementia is also rising. The principal concern, however, should not be the degree to which health services are affected, but the hideous nature of the illness itself. The patient is, after the early stages of the illness, usually (though not inevitably) mercifully unaware of most aspects of his or her condition (though patients with some forms of e.g. MID (see below) retain awareness). On the other hand, the effect on those left to care for the patient can be devastating. Usually, until the terminal stages of the illness, patients are not institutionalised. This means that the burden of care falls on the patient’s spouse or children. These caregivers (whom, it should be remembered, are often themselves middle-aged or older) have the task of tending to the needs of someone who has no memory, is incontinent, and subject to temper tantrums and other irrational behaviours. As an added bonus, many demented patients cannot even recognise their own spouse, children, or close friends. Thus, the reward for a lifetime’s love, affection and sharing can be to tend for a person who whilst outwardly resembling a loved one, has lost all indication of being a sentient being. No one de-

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serves to die in such an undignified fashion, and no-one should have to witness it happen to someone they have loved. Such an end would be tragic if it lasted several weeks, but for most patients the decline is gradual and takes place over years. To this should be added that in the UK at least, there will be precious little government help until the final stages of the illness, whereupon the local authorities are empowered to seize most of the patient’s estate to pay for the care. Thus, for example, a spouse may have to sell the family home in order to meet the bills (note also that few private health insurance schemes cover dementia). So the reward to caregivers for taking on a job which should be undertaken by the welfare state is not only to see their personal lives blighted but then to see financial security removed. Presumably this is what is meant by the modern ‘caring society’.

Dementia is thus a cause for major concern, doubly so since there are no known cures for its commonest forms. In this chapter, we shall examine the principal psychological features of the main types of dementia, although lengthy discussions of diagnostic procedures have been avoided, because they would occupy a disproportionately large part of the text, which is not in any case a guide to how to practise clinical psychology. For those interested in such considerations, a useful starting point is Parks, Zec and Wilson (1993), or Wasylenki (1987).

Classifying dementias

The first step in diagnosing dementia is to discover the extent of the handicap suffered by the patient when they first seek help. This may be hampered by the age of the individual in question. Younger adults with early symptoms of dementia are likely to go to a medical practitioner much sooner, because memory loss and other signs of intellectual decline are considered atypical in their age group. The decline may have to reach a rather more pronounced stage in older adults before anything unusual is noticed, simply because the early symptoms of decline may be taken as no more than ‘typical’ age-related loss.

Once the patient’s problem has been noticed, there are a number of basic measures of intellectual functioning which will provide a rough guide to the degree of impairment. A widely-used British test of this type is the Blessed Dementia Scale (Blessed, Tomlinson and Roth, 1968). In the USA, the equivalents are the Mental Status Questionnaire or MSQ (Kahn et al., 1960) and the Mini-Mental State Examination (MMSE). These ask the patient such memory questions as: ‘who is the current Prime Minister/President?’; ‘what is the day today?’; and ‘what is your name?’ In short, these are questions which no non-demented person should get wrong. The more questions the patient answers incorrectly, the greater the degree of

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their impairment, and the more pronounced their illness is held to be. In addition, a questionnaire on the patient’s behaviour may be given to a caregiver. This determines the extent to which the patient is still functionally independent, by asking questions such as the degree of help he or she requires in getting dressed. This has the dual advantage of not only giving a further gauge of the patient’s degree of impairment, but also judging the level of nursing care the patient requires. Scales such as the Blessed and the MSQ can also be used as the illness progresses, to keep a useful check on the general status and needs of the patient.

A more detailed method of describing the level of functioning of the demented patient is provided by Reisberg et al.’s (1989) Functional Assessment Stages, or FAST. The method was originally devised to describe the functional status of Alzheimer’s Disease patients (see below). Patients are placed into one of seven categories, with stages 6 and 7 divided into substages. Stage 1 describes normal functioning. In Stage 2, there are subjective feelings of loss of intellectual power, although these are not perceived as serious by other people. In Stage 3, intellectual impairment (particularly in memory) is evident in complex tasks which previously posed no problems, and in Stage 4, this has extended to relatively complex everyday tasks (e.g. ‘ability to handle finances’). Stage 5 is defined as ‘deficient performance in choosing the proper clothing to wear’, and in Stage 6, the patient is no longer able to dress him- or herself, or properly attend to personal hygiene (this stage is divided into five hierarchical substages, ranging from problems with dressing through to faecal incontinence).

Stage 7 describes the loss of motor and speech skills (six substages, beginning with the loss of speech through to ‘loss of ability to hold up head’). The authors also place estimates of the length of time a patient is likely to remain in a particular stage if he or she does not die during it (Stage 3 = 7 years; 4 = 2 years; 5 = 18 months; 6 = 2 years 5 months; 7 = 6 years +). A slightly simpler assessment is provided by the Clinical Dementia Rating (CDR), which is a checklist of level of functioning on a variety of tasks (e.g. memory, orientation, behaviour in the home). Based on the scores, the patient is graded as having no dementia, or ‘questionable’, ‘mild’, ‘moderate’, or ‘severe’

forms of the illness (Berg, 1988). The American Psychiatric Association periodically produces a taxonomy of mental illnesses, which is highly influential. The most recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (American Psychiatric Association, 1994) indicates that in addition to perceptual, intellectual and/or memory impairment sufficient to interfere with daily activities, these must be present when the patient is fully awake and with no evidence of intoxication (from alcohol or drugs). The illness is graded by its functional effect:

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mild (no supervision necessary); moderate (some supervision necessary); or severe (constant supervision required).

The different types of dementia (sometimes called dementias of different aetiologies or etiologies) all have the general characteristics described above. However, within this general decline, each has a unique pattern of dysfunction. We shall now consider the principal forms the illness takes.

Dementia of the Alzheimer Type (DAT)

The illness was first diagnosed in 1907 by Alois Alzheimer, in a case study of a 51-year-old woman, and is also known as Alzheimer’s disease (AD), senile dementia of the Alzheimer type (SDAT), and primary degenerative dementia (PDD) as well as dementia of the Alzheimer type (DAT). For the sake of convenience, the latter term is principally used in this book. DAT can occur at any age in adult life, but is incredibly rare before the age of 50, and thereafter, the probability rises, following the general rise in incidence for dementia described above. Commentators agree that DAT is the commonest of the dementias, but estimates of the precise proportion of dementias caused by DAT vary considerably, from circa 40–80 per cent or more (see Cohen and Dunner, 1980; Hestad, Ellersten and Klove, 1998; Smyer and Qualls, 1999). In part this variation is due to different regional and national diagnostic techniques, but a figure of about 70 per cent is not an unreasonable average figure.

As with dementia in general, the older the patient, the more advanced the illness usually is when he or she first presents for treatment. The reason for initially seeking help is typically severe memory failure well beyond the scope of everyday experience. This may include forgetting very simple lists or instructions, or getting lost in familiar surroundings, such as a local shopping centre or streets around the home.

Standardised memory tests will typically show a gross failure to remember new information for more than a few minutes or even seconds, and short term memory (STM) measures for digit span and similar may also show a decline. Patients may also show other symptoms, such as apraxia (inability to perform skilled movements) or visual agnosia (inability to recognise by sight). In some cases, these alone are the cause of the original referral, and the patient’s memory may be relatively unscathed.

Language may also be intact, although vocabulary may be impoverished. Patients may have difficulty in producing the appropriate words, and may fail to comprehend abstract phrases, such as proverbs. Patients’ responses to their symptoms vary. Some are depressed, others apathetic and unconcerned, others are aware of a problem, but either discount it or underestimate its severity. Others develop a paranoia that people are deliberately hiding things.

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As the illness progresses, so the severity of the above symptoms increases. Memory for new items is now severely curtailed, often even for items in STM. Memory for remote events, learnt before the onset of the illness, also worsens. Recognition declines, even to the point of being incapable of recognising friends and family (which obviously causes great distress). Language worsens considerably, and aphasia (language failure) becomes a key feature of the latter stages of DAT. The patient can have problems producing speech (Broca’s aphasia), understanding speech (Wernicke’s aphasia), or both. Speech can be reduced to a few words and a series of garbled speech-like sounds, or can consist of recognisable words produced in a nonsensical order. Sometimes the ability to read aloud is remarkably well preserved, with proper observation of punctuation and intonation (see Raymer and Berndt, 1996). However, patients have typically very poor recall of what they have read (demented dyslexia). The external appearance of the patients reflects their inward decline. Without the aid of dedicated helpers, the patients’ grooming and general demeanour inevitably worsen. Movement begins to appear crabbed and awkward. A shuffling gait, characteristic of Parkinsonism (see Glossary) becomes commonplace. In the terminal stages of the illness, the patient usually falls into an uncommunicative state. Incontinence becomes habitual. Often patients display Kluver-Bucy syndrome. This is a set of bizarre behaviours, including hyperorality (the urge to put everything seen into the mouth) and the associated problem of bulimia (the urge to eat vast quantities of food). The other symptoms of Kluver-Bucy syndrome are visual agnosia, hypermetamorphosis (the compulsive urge to touch everything) and a loss of affect (emotion). Death typically occurs about five years or more after the appearance of the first ‘major’ symptoms (though note there are huge variations between studies, depending on what is counted as a ‘major symptom’, etc). Certainly, length of survival after being admitted to institutional care has increased in recent decades (Wood, Whitfield, and Christie, 1995), probably reflecting improvements in general medical care. Death is most commonly ascribed to respiratory failure, presumably exacerbated by the relative immobility of patients in the later stages of the disease (see Burns, 1995).

The description of the stages of the disease has been deliberately kept loose.

There is immense variation between patients in the severity of their symptoms, the relative sparing of individual functions, and the length of time patients remain in each stage of the illness. However, a DAT patient who reaches the terminal phase of the disease will at some stage endure all the listed stages. A diagnostic test, specifically designed for DAT is provided by the NINCDS-ADRDA criteria. The initials refer to the ‘National Neurological and Communicative Disorders and Stroke’ and

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the ‘Alzheimer’s Disease and Related Disorders Association of America’, the two bodies who jointly devised the scheme. It provides three levels of certainty about the diagnosis: ‘probable’, ‘possible’ or ‘definite’. The final judgement can only be given when there is physiological proof from a biopsy of autopsy, so most researchers content themselves with a ‘probable’ diagnosis. This requires, amongst other factors, proof of functional handicap (as measured by the Blessed Dementia scale and similar), memory loss, ‘deficits in two or more areas of cognition’, and an absence of indicators of other courses, such as tumour, acute confusional state (see below) and so forth. Katzman, Lasker and Bernstein, (1988) note that the DSM criteria are probably equivalent in accuracy.

Some older textbooks restrict the use of DAT to cases arising before the age of 60
and use the term senile dementia to describe those occurring after this age. Others distinguish between a pre-senile and senile form of DAT. It is generally true that the illness is more pronounced (particularly in linguistic deficits – Seltzer and Sherwin, 1983) and progresses faster through the early stages in younger patients (Reisberg, Ferris, Franssen et al., 1989), although perversely enough, younger patients tend to survive longer in the later stages (e.g. Nielsen, Honima and Bjorn-Hendriksen, 1977). However, the set of symptoms of the two forms, though differing in strength of expression, are equivalent, and many researchers have argued that the older-younger division is specious (see Sulkava, 1982; Sulkava and Amberia, 1982; see Lezak, 1995, for an overview). Other researchers have argued that there is more than one form of DAT. Depending upon the author in question, this can mean that either: (a) there is more than one cause of the same symptoms; (b) the same cause can yield more than one set of symptoms, though they all bear sufficient in common to merit being given the same label; or (c) a permutation of (a) and (b). Added to this is the possibility that patients classified as suffering from DAT in fact have several conditions, which present diagnostic techniques are incapable of teasing apart. For example, at one stage there was thought to be one form of cancer. With improvements in medical science, it is now known that there are many different forms. Likewise, it is now known that the same type of cancerous cells can produce different symptoms in different bodies, and that the same cancer can have several different causes. Thus, the term ‘DAT’ may be covering a multitude of factors – small wonder, then, that there is such a variability in symptoms. To complicate matters yet further, there is also the issue of the age and intellectual status of the patient. We have seen that younger patients tend to have more pronounced decline. In addition, it is known that patients with higher levels of intellectual and/or linguistic skills are less prone to dementia (see Butler, Ashford and Snowdon, 1996; Hestad, Ellertsen and Klove, 1998;

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Snowdon et al., 1996). Therefore, in addition to possibly different types of DAT, the progression of the illness may be shaped by the age and IQ of the patient.

(Those unfamiliar with neurophysiology are advised to consult Chapter 1 before proceeding.)

The reason for introducing this element of confusion is more than just demonstrating that there are no easy answers to the question of DAT (or indeed any of the other dementias). It is also to point to extreme caution in interpreting findings of studies of the psychological characteristics of DAT patients. For example, suppose that we take what should be the most objective of measures – namely, the incidence of tissue decay in the brains of DAT patients, and gauge this against their psychological status. DAT patients, by the classical definitions, display characteristic patterns of brain cell decay. Aside from cell loss, some of the cell death leaves behind characteristic bodies, including neurofibrillary tangles and senile plaques, which are groups of dead brain cells which look like tangled string and solid lumps, respectively (for some excellent illustrations and a more complete explanation of the same, see Hyman et al., 1993). Cell loss is fairly selective, and is concentrated in the cortex (though the occipital region remains relatively undamaged), and some subcortical regions, principally the amygdala, the hippocampus and the brain stem (Moss and Albert, 1988). It is worth noting that some areas of the central nervous system are often spared, notably the basal ganglia, cerebellum and spinal cord (Petit, 1982). Given this pattern of damage, one would expect intellectual and memory functions to be affected, and indeed, early studies supported this, finding that there was a negative correlation between cell loss and level of intellectual functioning – in other words, as cell death increases, intellectual performance decreases (e.g. Tomlinson, Blessed and Roth, 1968). However, Katzman, Terry, Deteresa et al. (1988) found that some patients have a high number of plaques but no discernible signs of DAT. Conversely, other studies have found some patients with DAT symptoms in the absence of obvious neurological damage (see Hestad, Ellersten and Klove, 1998, for a review).

Again, it is known that output of neurotransmitters from the cholinergic system is severely depleted (Kermis, 1986). Since it is known that deliberately suppressing cholinergic activity impairs memory, it is tempting to assume that the cause of DAT
patients’ problems is lack of this transmitter. This is called the cholinergic hypothesis. However, there is ample evidence that cholinergic depletion does not usually cause all the types of memory loss shown in DAT (see Gottfries, 1996; Moss and Albert, 1988). Furthermore, neurotransmitters other than those in the cholinergic system are also known to be significantly depleted (Rossor and Iversen, 1986).

Therefore, the cholinergic hypothesis cannot provide a full explanation (although

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cholinergic therapy may nonetheless be beneficial, see Sirvio, 1999). Taken as a whole, these results could mean one of several things. First, neurological decay may be unrelated to demented symptoms. However, this is so improbable that it can be dismissed. Second, neurological decay may be offset by other factors. For example, higher education levels may mean that the brain can endure more decay before symptoms manifest themselves. However, this cannot explain dementing symptoms where there is no evidence of decay. Also, Gilleard (1997) argues that the higher the education level, the better the patient may be able to mask the symptoms – in other words, the protection afforded by education may not be as great as some other commentators have argued. This suggests a third reason – namely, that underlying the same set of symptoms may be several different causes.

The search for the causes of DAT has an obvious importance, since it may in turn indicate a cure or at least some prophylactic treatments. Given that the illness has several manifestations, it is reasonable to assume that there may be more than one cause.

Undoubtedly there is a genetic component in at least some cases of DAT, probably caused by the unfortunate combination of several genes rather than a single aberrant gene (Kidson and Chen, 1986). The search for the faulty genetic code is an area of active research. Some researchers (e.g. St. George-Hyslop et al., 1987; Schweber, 1989a) have found a flawed structure in chromosome 21, at a location close to that of the damage found in patients with Trisomy 21, the commonest cause of Down Syndrome. Many commentators have noted that Down Syndrome patients develop DAT-like symptoms in middle age, and that the neuropathology of the patients’

brains is very similar to that of DAT patients (e.g. Schweber, 1989b).

However, although there may be a genetic component to DAT, this does not mean that this is the sole cause. For example, if DAT develops within a family, then transmission of the illness is not automatic. If the son or daughter of a DAT patient develops dementia, then there is approximately a 50 per cent chance that his or her siblings will do likewise. These cases are likely to develop at a pre-senile age (i.e. <60
years) and develop faster (Heston et al., 1981; see Lezak, 1995, for an overview).

Thus, DAT can develop in people with a particular genetic makeup, but it would be wrong to move further from this position to argue that people with ‘DAT genes’ will inevitably become demented provided they live long enough. For example, there is an under evens chance of only one of a pair of identical twins developing DAT (Jarvik, 1988). Since identical twins have an identical genetic structure, clearly more than just genes must cause the disease to occur. The most likely explanation is the threshold model of dementia, which states that a person’s genetic makeup may predispose them to develop DAT, but it requires something in the environment to trigger the on-

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set of the disease. A number of candidates for this lurking menace in the environment have been suggested. In recent years, aluminium has been suggested as a likely cul-prit. This is because brain cells in DAT patients have been found to contain tiny grains of the metal. Some worried people stopped using aluminium cooking utensils and similar; probably a futile gesture, since aluminium is a very common element, present in a great many ‘natural’ things and foodstuffs. Why DAT patients are especially vulnerable to aluminium is still something of a mystery. It is possible that the aluminium uptake is a symptom rather than a cause of the decline. For example, dying cells within a DAT patient’s brain may just happen to absorb aluminium, rather than the aluminium causing the cells to die. This is illustrated by the finding that attempting to restrict aluminium uptake into the brains of DAT patients does not affect the progression of the illness (Shore and Wyatt, 1983). Another proposal is that the illness is caused by a slow acting virus. It is known that some dementing illnesses such as kuru (which affects a few native tribes in Papua New Guinea) can be caught by handling diseased nervous tissue. However, generally the evidence on DAT is inconclusive (Lezak, 1995). A severe blow to the head may trigger some cases of DAT, but again, the evidence is inconclusive.

Vascular dementia (VaD)

This is an umbrella term referring to dementia caused by damage to the blood vessels within the brain. This may be due to a blood vessel becoming blocked by a clot forming (thrombosis); a detached clot lodging in an artery (causing an embolism); or a rupture in the wall of a blood vessel (a haemorrhage) causing damage to the surrounding tissue. The damage in turn causes the surrounding brain tissue to die, the dead tissue being called an infarct. VaD is the second commonest form of dementia, and together with DAT makes up about 90 per cent of all cases of dementia (Lezak, 1995; Smyer and Qualls, 1999). Nearly all cases of VaD come from a subgroup called multi-infarct dementia (MID). This is characterised by the patient’s brain suffering a succession of infarcts, none of which in themselves may cause noticeable changes in behaviour, but which taken together cause dementia to occur. These infarcts can be anywhere in the brain and be relatively random. In some cases they can be concentrated into particular regions of the brain. In cortical atherosclerotic dementia (CAD) the damage is largely in the cortex, whilst in subcortical arteriosclerotic dementia (SAD), damage is principally in the sub-cortical regions.

As might be predicted, CAD is associated with greater intellectual impairment, SAD
with movement disorders (see Metter and Wilson, 1993). Two common forms of SAD are lacunar strokes and Binswanger’s disease, which have similar symptoms

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though their origins are in damage to different subcortical areas. The identification of MID as a condition distinct from stroke (a single infarction) is relatively recent (Hachinski et al., 1974). It is worth noting, however, that misdiagnosis of MID
patients as stroke victims and vice versa is not unknown (Funkenstein, 1988). The causes of MID are not fully known. Not surprisingly, patients often have a history of cardiovascular (CV) problems, and there may also be some familial tendency to MID
or stroke. It is also known that a number of CV illnesses can be the trigger for MID

(Funkenstein, 1988). The illness is extremely rare before the age of 55, with average onset at 65. A common method of testing for MID is the Ischaemic Rating Scale, also known as the Hachinski Ischaemic Score (IS), after its inventor (Hachinski et al., 1975). This awards points to the patient, based upon the number of symptoms they display, with particularly salient symptoms being weighted to reflect their greater importance.

Because infarcts occur reasonably randomly in MID, the course of the illness is difficult to predict, and symptoms can vary greatly between patients. For example, as with DAT, the simple quantity of brain tissue destroyed by MID bears little relationship to the symptoms produced (see Metter and Wilson, 1993). To quote one researcher, ‘there are few findings that can be considered consistent with a diagnosis of MID’ (LaRue, 1992; p 236; author’s italics). This is because the areas of the brain controlling different mental functions may decay at different rates (according to where the infarcts most frequently strike). To take an example: suppose that there are areas of the brain called A,B,C,D, and E, controlling abilities X,Y,Z,P, and Q
respectively. One MID patient may show a decline in areas A,B, and C, and thus in abilities X,Y and Z. Another patient may have well preserved areas A and B, but show decline in areas C, D and E, and thus in abilities Z, P and Q. Thus, two patients with the same basic complaint may have radically different symptoms. It will not have escaped some readers’ notice that, because infarcts can occur relatively randomly, in some instances the damage they inflict can by chance mimic the effects of dementias of other aetiologies, and thus misdiagnosis is common. Largely because of this, a precise estimate of the incidence of MID is difficult to obtain (see Metter and Wilson, 1993). The problem is confounded by the existence of some forms of dementia in which symptoms of MID, or more generally VaD, coexist with symptoms of DAT -
together these are known as AD-MID. Alafuzoff et al. (1989) suggest that patients with AD-MID display symptoms which are more than just a combination of DAT
and MID, but it is possible that the more pronounced of these symptoms are simply the products of an interaction between the two conditions. To even further muddy the waters, some patients with DAT may also have infarcts, which although they

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appear to occur separately from the atrophy of tissue associated with ‘pure’

Alzheimer’s patients, may exacerbate the condition (see Snowdon et al., 1997).

Nonetheless, there are aspects of ‘pure’ MID which make it distinguishable from other dementing disorders. For example, the onset of the symptoms can in some cases be quite sudden: there may not be the insidious development seen in other dementias.

However, some MID patients (e.g. Binswanger’s disease patients) display a progressive onset, so this is not an infallible identifying feature. MID patients also almost invariably have a history of CV illness. This can be true of other demented patients, but a lengthy history of strokes, high blood pressure and similar will provide a strong indication that MID or another form of VaD is probable. However, the cardinal difference is in MID’s development. While patients suffering from other dementias typically show a steady rate of decline, MID patients show a stepwise, jerky decline.

In other words, they tend to stay at one level of ability (and may even show some temporary improvement) for weeks or months, before suddenly worsening to a lower level. This process then repeats itself, with each decline removing more of the patient’s intellectual powers. Because the infarcts tend to occur relatively randomly, the progression of symptoms is hard to predict, although memory is typically an early victim. Progressively more of the patient’s intellectual status is whittled away until he or she is reduced to a vegetative state. Death usually occurs from a CV-related illness (such as a heart attack) or opportunistic infection, on average about 4 years after initial diagnosis.

Other dementias

Although MID and VaD between them account for most cases of dementia, as mentioned above, there are nearly 50 other known causes. Of these, the following are perhaps the most often encountered. Pick’s disease (named after its discoverer) is not commonly a disease of later life, with the average age of onset in the late forties.

Atrophy begins and is concentrated in the frontal lobes, spreading to the thalamus, basal ganglia, and amygdala (see Lezak, 1995). At a cellular level, neurons often degenerate into Pick’s bodies, which have a characteristic swollen appearance. Note that some patients can have the same general pattern of atrophy as Pick’s disease, but lack Pick’s bodies. Recent clinical practice is to classify such patients as suffering from frontal lobe dementia (which has a same general pattern, though with a relative sparing of the thalamus and amygdala but greater decay in the parietal cortex, see Lezak, 1995). The patient usually first presents with problems expected of frontal lobe damage, such as loss of planning skills, ability to think in the abstract, and so forth. Kluver-Bucy syndrome usually manifests itself early in the course of the illness

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(as opposed to the late stages of DAT). It may also incorporate compulsive sexual behaviour, often without regard for social propriety. As the disease progresses, dementing symptoms akin to DAT begin to manifest themselves. Often language is more impaired than memory, but this is not an infallible rule. Pick’s patients are also more prone to confabulation (essentially, making up stories or implausible explanations to cover up gaps in memory or other skills), something rarely seen in MID or DAT patients. In the terminal stages, the patient is reduced to a vegetative state. Death is typically about 4 years after the onset of the first symptoms.

Creutzfeldt-Jakob Disease (CJD) is a very rare illness, affecting approximately one in a million people. The illness typically manifests itself first as a movement disorder before intellectual deterioration begins. The illness is atypical of dementias in two main respects – first, death is usually swifter (circa 1 year after onset of symptoms) and it is known that it is contracted via an infection. At the time of writing, CJD
is of especial interest because a new variant of the disease (nvCJD) has been discovered. So far, only about 40 or so individuals have contracted it. There is strong evidence that the infection source may be beef contaminated with bovine spongiform encephalopathy (BSE), an infective agent which produces symptoms similar to CJD
in cattle. Although some of the more excitable media speculations about an epidemic of nvCJD have so far proved unfounded, the fact that dementia may be contracted through eating a common foodstuff is clearly alarming. However, at the time of writing, definitive proof that this is the route of infection has yet to be produced (see Stuart-Hamilton, 1999a).

Huntington’s disease (a.k.a. Huntington’s chorea) is not considered to be a dementia by all commentators. Like CJD, it is relatively rare, but it tends to cluster in families, indicating a strong genetic component. Also like CJD, the early symptoms of the illness are disturbances of movement, often taking the form of writhing and twitching. Subsequently, patients develop dementing symptoms, although the decline can also mimic schizophrenia (Kermis, 1986). Patients with Huntington’s disease tend to last longer than patients with other dementias, typical life expectancy after the appearance of the first symptoms being circa 15 years. The illness can strike at any age, but onset in middle age is commonest. Parkinson’s Disease (PD) is also chiefly characterised by movement disorders, including a characteristic shuffling gait and tremors. However, there is a higher than average risk that PD patients will also develop dementia (about 10–15 per cent: Lezak, 1995; Moss and Albert, 1988). It should be noted that many DAT patients develop PD-like symptoms as their illness progresses. The most salient difference between PD and DAT patients is that linguistic skills are usually considerably better preserved (or even unaffected) in PD

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(LaRue, 1992). Dementia can also appear as a symptom of other illnesses, such as normal pressure hydrocephalus (where cerebrospinal fluid gets trapped in the brain instead of draining away, putting destructive pressure on the brain tissue), brain tumours, and AIDS; and also as a result of long-term exposure to toxic chemicals and chronic alcohol abuse.

Cortical and subcortical dementias Some commentators prefer to categorise dementias according to whether the principal atrophy is in the cortex (the cortical dementias) or in the subcortical regions (the sub-cortical dementias). By this reckoning, the commonest cortical dementias are DAT and Pick’s disease, and the commonest subcortical dementias are PD and Huntington’s disease (with types of VaD belonging to either group, depending upon the particular form in question).

Since the cortex is principally concerned with higher intellectual functions and the sub-cortex with the control of movement, emotion and so forth (see Chapter 1), there should be a functional division between the two groups, and this is what is typically found. Thus, cortical dementias manifest themselves most strikingly as disorders of thought, memory and language, with some movement disturbances as relatively minor symptoms, whereas subcortical dementias are very much characterised by problems with movement (for this reason amongst others, some commentators have argued that subcortical dementias are not ‘true’ dementias). Subcortical dementias also tend to strike before the onset of later life. There is an excellent review of the issue by Peretz and Cummings (1988).

Illnesses which can be confused with dementia An assortment of conditions can give the appearance of dementia but in fact have other causes. The two commonest of these are both treatable, unlike the dementias, and for this reason are sometimes called the reversible dementias. The first of these is pseudodementia. This can arise in some older people who suffer severe depression (see later). In becoming depressed, the patient loses motivation and this is reflected in very poor scores on tests of memory and intellect. This, and their general lack of interest in their surroundings, can provide an excellent imitation of dementia. Indeed, some commentators argue that the impersonation is so good that the term ‘pseudodementia’ is misleading and that the illness should be classified as a form of ‘true’ dementia. However, there are several key differences between pseudodementia and the genuine article. First, pseudodemented patients are usually well orientated in time and space; for example, they know where they are, what day of the week it is, why they are being tested, and so forth. Second, they are also typically aware that they are performing badly on memory and intellectual tests. Third, pseudodemented patients’ intellectual performance typically fluctuates in tandem with their level of depression, and improves as

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their depression is treated (Jenike, 1988; La Rue, 1992). However, it would be misleading to suppose that depression and ‘genuine’ dementia have no connection. Between 20 and 30 per cent of patients with DAT, MID, or other dementing symptoms caused by atrophy also have some symptoms of depression (e.g. Marsden and Harrison, 1972; see also Boland et al. , 1996). Again, it is salient to note that one study found that 57 per cent of older patients referred for treatment for depression subsequently developed dementia (Reding, Haycox and Beas, 1985). In other words, severely depressed older people may display pseudodementia, but equally, a high proportion of ‘genuinely’ demented patients may also display depression.

The other major impersonator of dementia is acute confusional state (ACS) also known as delirium. ACS is typically rapid in onset (usually a matter of hours or days). The age groups most at risk are children and older adults. There are many possible causes, including: fever, infection, (legally prescribed) drug intoxication, stroke, and inadequate diet (particularly one with a deficit of vitamin B12). Most cases of ACS are cured by treating the underlying causes. Delirious patients display poor intellectual and memory skills, and also tend to be either excessively languid or alternatively hyperactive. Rambling or incoherent speech is also a common feature. To this extent, a patient with ACS can resemble a demented patient. However, a major difference between ACS and dementia, other than the rapid onset of the former, is that many delirious patients suffer from illusions (distorted perceptions of the world around them). Illusions are relatively rare in dementia, in spite of some popular misconceptions on this subject. In addition, attention span in ACS is limited, whereas (surprisingly) it is often reasonably well preserved in demented patients. Various diagnostic tests, which act as a checklist of symptoms (e.g. the Delirium Rating Scale) are available.

Problems with diagnosis and testing

Clinicians tend to diagnose dementia by default. In other words, a patient is labelled as demented after other possibilities (depression, fever, tumours, etc) have been ruled out. Discrimination between dementia and pronounced (but non-dementing) ageing change is fraught with problems when the dementia is only in its early stages (see Woods, 1999, for an excellent discussion of this). However, diagnosis of the type of dementia is fraught with equal, if not larger, problems. Because different dementias can share similar sets of symptoms, accuracy is often low, with 30–50 per cent of misdiagnosed cases being not unknown (see Gurland and Toner, 1983; Lezak, 1995; Roth, 1979). It might be supposed that brain scanning techniques might improve identification, and to some extent they do, but it has already been seen that, first,

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some patients’ physical and psychological symptoms do not ‘match up’, and second, within the same disease, several patterns of atrophy may be found, which may be confused with dementias of different aetiologies (see Charletta, Bennett and Wilson, 1993). This raises problems for treatment. If diagnosis is uncertain, then the treatment given may be inappropriate. Since drug therapy for dementia is still in its fledgling stages, this means that getting accurate feedback on the efficacy of treatments is very difficult indeed. Aside from this, there is the equally important consideration that the relatives of demented patients cannot be given an accurate prognosis of the expected length of survival, the likely path of the decline, and so forth.

From a researcher’s viewpoint, the lack of accurate diagnoses means that it is very difficult, if not downright impossible, to assemble a group of patients and know for certain that they are all suffering from the same form of dementia. Thus, finding a difference between a group of patients suffering from DAT and another suffering from MID on a particular test may mean there is a genuine difference between DAT
and MID patients on the skill measured by that test. However, this conclusion must be weighed against the consideration that at least some of the DAT group may be suffering from MID and vice versa. Another problem is in matching patients with different forms of dementia. It is not really sufficient to assemble a group of DAT
patients, a group of MID patients and compare them, without also considering how long the patients in each group have been diagnosed as suffering from their respective illnesses. If, for example, the MID patients have had the illness longer than the DAT patients, how can we be sure that any difference between the groups is not due simply to the length of having the illness rather than any intrinsic difference between DAT and MID? Again, are the groups of the same average age – if not, any difference might be due simply to ageing rather than the illness. Conversely, if the groups are of the same average age, are they typical of their illness groups? For example, suppose that on average, dementia A strikes at 60 years of age, and dementia B at 70. If we test an A group and B group, and both have an average age of 70, how can we be sure that there is not something slightly unusual about the A group. (In other words, is it truly representative?) To take yet another possible problem.

Suppose that it is found that patients with, for example, DAT, are very bad at remembering spoken words. It might be supposed that this indicates a poor verbal memory. However, dementia, and particularly DAT, is Murphy’s Law applied to intellectual functioning – in other words, whatever can go wrong, will go wrong.

Thus, finding a failure of verbal memory may mean there is a decline in verbal

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memory, but perhaps a decline in linguistic skills meant that the patient simply did not understand the test instructions.

None of these problems is necessarily insurmountable, but they do indicate that extreme caution must be taken in interpreting the results of studies of dementia. Certainly it is nearly always unwise to pursue points in any great detail, simply because the initial diagnosis and the problems of accurately comparing different patient groups are too problematic for more than fairly general statements to be made with any certainty.

Memory changes in dementia

Since memory loss is a defining feature of most forms of dementia, it is unsurprising to note that many studies have found general deterioration of memory in patients with dementia, and that generally, the more advanced the disease, the worse the memory. Of greater interest are differences between dementias in the severity of memory loss and the degree to which different types of memory are spared or lost relative to each other within the same illness. Unsurprisingly, most of this research has concentrated on DAT.

It can be readily established that, as for non-dementing older people, DAT patients’ performance on short-term memory (STM) tasks worsens the harder the memory task set (e.g. Nebes, 1992). A sizeable cause of this deficit may be an encoding problem. For example, Kopelman (1985) found that DAT patients could retain memories as well as non-dementing participants, provided they were given (a lot) more opportunities to rehearse the to-be-remembered (TBR) items. Thus, if information can get into a long-term store in DAT patients’ memories, then there is a reasonable possibility that it will be retained. Further evidence for this assumption comes from Becker et al. (1987), who found that within 30 seconds of being given a set of TBR
items, DAT patients had forgotten a significant proportion of them. However, those items which were remembered after 30 seconds had the same probability of being remembered 30 minutes later as did items which non-dementing control participants remembered after 30 seconds (see also Hulme, Lee and Brown, 1993). Again, there is evidence that memory stores are still functioning in the same qualitative manner as non-dementing participants’. For example, memory of verbal materials is presumed by most commentators to be stored on a phonological loop. This mental mechanism is believed to work not unlike a ‘voice in the head’ talking on to a continuous tape loop. As has been demonstrated on many occasions in non-dementing participants (see Baddeley, 1986), if given a set of TBR items which sound similar (e.g .

B,C,D,V,G) , the phonological loop stores them less well than when faced with dissim-

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ilar-sounding items (e.g. H,W,J,Y,E). DAT patients remember less overall, but are relatively speaking just as prone to having memory lowered by phonological similarities in TBR items (Morris, 1984).

An optimistic interpretation of this is that if encoding problems could be overcome, DAT patients’ amnesia could be overcome. However, studies such as Kopelman’s have tended to use patients in the very early stages of the illness. What is being stated is that encoding is the first aspect of memory to decline – where it has led, other aspects of memory may follow. For example, Collette et al. (1999) report that whilst the phonological loop is unimpaired in early DAT, there is a decline in patients with more advanced forms of the disease. The same general finding of inexora-ble worsening is true for most other dementing illnesses. For example, Martone et al.

(1984) found comparable encoding problems in Huntington’s disease patients. Perhaps not surprisingly, patients with pseudodementia behave like non-dementing older participants, though with an overall lower memory span (e.g. Gibson, 1981; Miller and Lewis, 1977).

At least in the early stages of DAT, Baddeley (1986) and other commentators have argued that the slave systems in working memory are functioning relatively unscathed, and that the deficit is in the central executive. There is considerable evidence that when given an STM task and a simultaneous distracting task, DAT patients’

memory spans get disproportionately worse the harder the distracting task is made (Morris, 1986). This strongly indicates a deficit in the central executive, since one of its main functions is to control and co-ordinate intellectual and memory tasks (Baddeley et al., 1991; Morris, 1994; Morris and Kopelman, 1986). The central executive is felt to be anatomically based in the frontal lobes (Baddeley, 1986), an area known to be badly affected in DAT.

An important caveat to the above concerns the apparent similarity between dementing and non-dementing ageing effects on working memory. In both cases, a decline in memory capacity seems to be attributable to failings in the central executive and more generally, the frontal lobes. However, as Baddeley (1986) and other commentators have pointed out, the decline in non-dementing older people is largely quantitative only – in other words, the processes at work in non-dementing older adults are largely the same as those at work in younger adults. An illustration of this is provided by Stuart-Hamilton, Rabbitt and Huddy (1988), who tested groups of MID, DAT and non-dementing older adults with very low IQ test scores. The researchers gave the participants the task of remembering sequences of movements in which an array of shapes had to be tapped in the order prescribed by the experimenter. MID and non-dementing participants remembered longer sequences when

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the shapes were coloured and had different outlines than when the shapes were all black squares of identical size. For DAT patients, the reverse was true. This indicates that the variety introduced by the colour and shape aids non-dementing people but hinders DAT patients. It is hypothesised that this was because colour and shape can be used as extra memory cues by non-dementing people, but the DAT patients cannot cope with the extra information this presents, and so in effect get confused. However, of key interest here is that DAT patients and non-dementing older participants performed in qualitatively different ways.

Remote memory is also affected by dementia. Although it is sometimes popularly supposed that demented patients have no memory for yesterday but a pin-sharp recall of events from their childhood, this is not the case (except in the very early stages of the illness when the memory problem may be for new information alone). Formal laboratory studies have demonstrated that remote memory for famous names and events is significantly worse than for non-dementing older people (e.g. Corkin et al., 1984; Wilson, Kaszniak and Fox, 1981), and declines at a greater rate than autobiographical memory (Greene and Hodges, 1996b). Some studies have found that memory for more distant events is better than for recent ones (see Nebes, 1992), but others (e.g. Corkin et al., 1984; Greene and Hodges, 1996a) have found memory to be better for recent events, or for items from different time periods to be remembered equally well (Wilson et al., 1981). The pattern of recall produced may rest on the types of names and events used, and may simply be an experimental artefact. However, what is certain is that overall, remote memory is worse in demented patients.

Whilst such findings do not completely disprove the argument that storage and retrieval mechanisms are intact in demented patients, and that the principal deficit is in encoding, they certainly raise interesting questions about why events stored long before the onset of illness can now not be retrieved if storage and retrieval are intact.

Greene, Hodges and Baddeley (1995) attributed their finding of a decline in autobiographical memory in DAT patients to a retrieval problem, in turn linking this to a failure of the central executive.

The above studies raise the question of whether demented patients’ memory problems can be alleviated. Certainly some common-sense procedures seem to help.

For example, priming the patient with the first letter of a TBR item produces a disproportionate improvement in the memory performance of demented patients (e.g.

Davis and Mumford, 1984; Miller, 1975). However, priming has to be fairly unsubtle to be efficacious. For example, priming with a word semantically related to the TBR
item, or giving lists of words semantically related to each other, has no advantageous

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effect on dementing patients, though non-dementing older adults are advantaged by this (e.g. Davis and Mumford, 1984).

Linguistic skills and semantic processes

One of the commonest measures of linguistic skills is a simple naming task, in which the patient must identify pictures of common objects. Failure to name objects (anomia) is a common first symptom of DAT, and DAT patients are notably disadvantaged when compared with not only non-dementing controls but also patients with Huntington’s disease, PD and MID patients (Bayles and Tomoeda, 1983; Chan et al. 1995; Schram, Rubert and Loewenstein, 1995). It is suggested that this deficit is in part due to the degeneration of the storage of this information. In a similar vein, Chan et al. (1995) found that the manner in which semantic interrelationships are stored is radically different in DAT patients compared with non-dementing participants and patients with Huntington’s disease. Several researchers (e.g. Warrington, 1975; Martin and Fedio, 1983; Schwartz, Marin and Saffran, 1979) found that as DAT progresses, words for specific items and events tend to be lost before more general words, implying a loss of detail from the system.

However, a cautionary note is raised by Nicholas et al. (1996), who argue that the disproportionate deficit in DAT patients may be due to the method chosen to score errors, and that another arguably equally viable method shows no especial disadvantage. Other researchers have also argued that the size of the difference can be ameliorated by the test methods used (see Nebes, 1992; Nebes and Brady, 1990).

However, this is largely a debate about the magnitude of the effect, not the effect itself. Certainly an especial problem with semantic memory may explain the failure of semantic cues to facilitate memory in DAT patients (though see Carlesimo et al., 1995). The semantic deficit may also in part be due to a decline in working memory, particularly in judgements of phrases or similar, where several words must be kept in mind simultaneously (see Kemper, 1997). Brain scans reveal a complex pattern of atrophy associated with different linguistic deficits (see Harasty et al., 1999; Hirono et al., 1998; Keilp et al., 1999).

Linguistic problems are not confined to anomia and related semantic problems, however, and generally, linguistic skills worsen as DAT progresses. For example, Grossman et al. (1995) found that DAT patients were significantly poorer on a range of linguistic tasks (sentence-picture matching, judgements of the grammatical acceptability of sentences, sentence completion), which was not explicable by memory deficits nor indeed the supposed severity of the illness (though note that linguistic deficits in DAT do not appear with the same severity at the same stage in all patients).

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Common symptoms include intrusions (inserting inappropriate words or phrases), perseverations (repeating the same phrase, word, or part of a word); and circumlocution (talking around the subject).

Not all linguistic skills will decline at the same rate, however. For example, phonology (awareness of speech sounds, as shown, for example in correct pronunciation), and morphology (knowledge of the roots of words) are generally well preserved in DAT (e.g. Appell, Kertesz and Fisman, 1982). Again, reading (at least of single words) is assumed to be relatively well preserved in at least the early stages of DAT. This is countered by Patterson, Graham and Hodges (1994) and Storandt, Stone and LaBarge (1995), who found significant deficits in NART performance (see Chapter 4) in a group of patients with very mild DAT. This contradicts the accepted wisdom of using the NART as a gauge of pre-illness intelligence. However, other researchers (e.g. Law and O’Carroll, 1998) have found relatively little change. Glosser, Grugan and Friedman (1999) suggest that what deficit there is may be due to other intellectual and/or memory problems rather than a specific reading deficit, whilst Strain et al. (1998) concluded from their study that a reading deficit only occurs when there has been an appreciable decline in semantic memory.

Visuo-spatial skills

Declines in visuo-spatial skills have been found in patients with very mild DAT, even when memory demands of the task are minimised (Bucks and Willison, 1997; Kaskie and Storandt, 1995). Armstrong and Cloud (1998) attribute the decline to the reduced efficiency of components of the working memory system. Some visuo-spatial skills are not as reliable discriminators between DAT and non-dementing people, however. For example, a commonly-used task is the clock drawing test (CDT), in which the participant must copy an analogue clock face. Lee et al. (1996) found that although DAT patients’ performance declined, the more severe their dementia became, in the very early stages of the illness, their performance was not always distinguishable from non-dementing participants. Cahn et al. (1996) also question the use of the CDT as a screening test when used on its own. However, such concerns over diagnostic accuracy of one test should not blind the observer to the simple general truth that visuo-spatial skills are generally very poor in DAT (see Lezak, 1995). This can be seen in skills as diverse as copying simple displays of crosses (Grossi and Orsini, 1978) and iconic memory (Coyne et al., 1984; Moscovitch, 1982; Schlotterer et al., 1984).

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Olfaction

Olfactory functions (i.e. smell) worsens in DAT. For example, Nordin and Murphy (1996) found that DAT patients had a higher odour threshold (i.e. the smell had to be more powerful before it was detected), and poorer memory for smells. In a review of the literature, Thompson, Knee and Golden (1998) conclude that olfactory problems are effective in distinguishing between DAT patients and non-dementing older adults, and may also be effective in distinguishing DAT from some other forms of dementia (e.g. Huntington’s disease: see Murphy, 1999; though not e.g. Parkinson’s Disease: see Mesholam et al., 1998).

The effect on caregivers

All forms of illness can have negative effects not just on patients but also on those family members and friends who look after them. However, the effect may be particularly strong on caregivers for demented patients, because the nature of the illness means that the patient cannot give adequate feedback. It takes little imagination to envisage the unique stress induced by looking after a spouse or a parent who needs constant attention and yet who cannot even recognise their caregiver. Levesque, Ducharme and Lachance (1999) demonstrated in a large-scale study of caregivers that the stresses experienced by people looking after demented patients are significantly greater than in caring for patients with other illnesses. Also, caregiver burden is generally higher in younger than older demented patients (Freyne et al., 1999), and VaD patients present greater problems than DAT patients in the early stages of the illnesses, with a reversal in the later stages (Vetter et al., 1999).

Not surprisingly, there is a large body of evidence that caring for a demented relative usually results in significantly higher levels of depression, stress, and other related health problems (e.g. Coppel et al., 1985; Kennedy et al., 1988; Morrisey et al., 1990). Suicide risk is also higher (Fry, 1986). It should also be noted that because of the immense pressure the caregiver is placed under, elder abuse is not uncommon (e.g. Compton, Flanagan and Gregg, 1997; Cooney and Wrigley, 1996; see Wolf, 1997, for an overview). Note that this does not necessarily imply violence, but may include nonetheless undesirable behaviours such as neglect (see Pritchard, 1995).

The social role of the caregiver is a key determinant of the level of adverse effects experienced. Morrisey et al. (1990) found that spousal caregivers who did not have paid employment (they were homemakers) cited loss of social contacts and disruption to household chores (as well as the severity of the spouse’s handicap) as the chief causes of depression. Caregivers in paid employment cited the severity of the spouse’s handicap as less serious, and the disruption to household chores as more

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serious than the homemakers. Curiously, a large number of friends and relatives alleviated the homemaker’s depression, but made it worse for the paid workers.

Morrisey et al concluded that this was because the paid workers’ friends included workplace colleagues who may inadvertently add stress by offering social interaction, but not practical help. Schulz and Williamson (1991), in a two year longitudinal study, found that male caregivers tended to get more depressed as time passed, whilst female caregivers remained at the same level. These findings might be compromised by not knowing the levels of depression prior to the onset of the illness, but Dura et al. (1991), with greater baseline measures, also found that depression increased over time.

Some factors can make a difference to the well-being of caregivers. For example, practical assistance, and financial security (e.g. Pruchno and Kleban, 1993) are obvious examples. Again, providing training for caregivers can be advantageous (see Teri, 1999; and commentary by Gilhooly, 1999). Again, there are probable cultural differences. In a review of the literature, Connell and Gibson (1997) found that in non-White communities, caregiving is more likely to be by a younger relative or friend rather than the spouse, and that generally, a lower negative state is reported.

Religious faith and practice also played a stronger role.

However, at the level of individuals, the relationship is not necessarily clear-cut.

For example, Rivera et al. (1991) found no difference between depressed and non-depressed caregivers in their level of satisfaction with the support offered. This indicates that individual differences in the psychological characteristics of the caregivers may also play a role. For example, Cicirelli (1993) found that daughters caring for their mothers who felt a strong feeling of emotional attachment reported a lower level of burden, whilst feelings of obligation increased this. Again, Rapp et al. (1998) found that the level of social resourcefulness displayed by individual caregivers was significantly related not only to their level and type of social interaction, but also their level of well-being.

Summary

Dementia is a progressive loss of memory, intellectual and linguistic skills, usually accompanied by radical changes in personality and sometimes in motor skills.

Symptoms vary markedly between patients, but generally the different dementias are distinguishable by their patterns of development. Several illnesses can be confused with dementia because of a superficial similarity of symptoms, but these can usually be easily identified. At a physical level, dementias often differ in patterns and type of atrophy, but as has been seen, the correlation between damage and psychological

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symptoms is far from watertight. Almost all intellectual functions decline in dementia (particularly DAT, where research has been most concentrated). Although there are some interesting qualitative differences in functioning, it should be noted that these are usually only found in patients in the very early stages of the illness – as the disease progresses, patients usually lack sufficient psychological skills to comprehend or perform the tasks presented to them. It must also be remembered that in dementia, like many other illnesses, it is not only the patient who suffers, and that the disease can be a great source of stress and burden to caregivers.

In closing this section, it is worth noting that the severity and awfulness of dementia’s symptoms can lead to an exaggerated view of its prevalence. Thus, it is worth repeating that only 5–6 per cent of all older people will develop dementing symptoms, and that many will be only mildly demented at death. It is also inaccurate to perceive dementia as solely a disease of later life, as though it is an inevitable consequence of ageing. As has been seen, all dementias can begin prior to the onset of later life, and some, indeed, are rarely seen past the age of 65. Furthermore, the psychological performances of demented patients are qualitatively different from those of non-dementing older people, thereby demonstrating that dementia is not a natural extension of the ageing process. Woods (1999) amongst others (e.g. Cohen, 1996) has suggested that because dementia in the very early stages is hard to distinguish from non-dementing ageing, that a continuum exists. This is plausible, but one could equally argue that at the start of many illnesses, a patient still shares many of the characteristics of a well person. However, that does not stop them having a distinctly different state of health.

Depression

Depression is a condition which almost all people experience in a relatively mild form many times in their lives. In most cases, the feeling of melancholy is in reaction to a specific event, disperses in a few days, and would not typically be considered a mental illness. Depression meriting clinical attention is long-lasting, and severe enough to interfere with normal functioning. It is important to stress that clinical depression is not solely ‘feeling down’ – the patient is in effect incapacitated by the condition. In addition to a depressed mood, he or she is typically lacking in both mental and physical energy to an extreme degree, has irrational feelings of worthlessness and/or guilt, and may have preoccupations with dying and suicide (generally, older patients have a greater preponderance of physical symptoms – Caine et al., 1994). Depression of this magnitude is far less common in later life than in any

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other age group; however, isolated symptoms of depression are far more frequent (Kasl-Godley, Gatz and Fiske, 1998; Smyer and Qualls, 1999). The latter finding is probably due to older people being exposed to a higher proportion of depressing events, such as bereavement, painful illness, and so on. It is also worth noting that older depressed people run the risk of developing pseudodementia (see above; estimates of the prevalence of pseudodementia vary wildly between studies; however, Kasl-Godley, Gatz and Fiske’s estimate of circa 11 per cent is a plausible average). This can hamper making an accurate diagnosis (see above and also Lezak, 1995).

Causes of depression in later life are often attributed (unsurprisingly) to stressful and negative events. For example, bereavement is known to cause depressive symptoms (see Chapter 5), though these in most instances are relatively short-lasting, and are not typically apparent after one year (see Kasl-Godley, Gats and Fiske, 1998; Smyer and Qualls, 1999; Woods, 1999). Again, illness and medical treatment side-effects can cause or exacerbate depression in some patients (see Sadavoy et al., 1995). Penninx et al. (1996) report that depressive symptoms increase with the number of illnesses from which the patient suffers. In addition, some diseases seems to be more conducive to depression than others: perhaps unsurprisingly, conditions which create chronic pain, such as arthritis, were found to be more likely to be associated with depression than were serious but less painful conditions such as diabetes.

Beekman et al. (1997) argue that an even stronger predictor of depression is level of physical health as opposed to disease; in a similar vein, Palinkas, Wingard and Barrett-Connor (1996) found depression to be significantly greater in obese older people. Psychological status may also be an important factor in some cases, with various real or imaginary declines in capabilities, such as dementia (e.g. Forsell and Winblad, 1998; also see above) and memory loss (e.g. Collins and Abeles, 1996; see also Chapter 3) correlated with depressive symptoms. More generally, lifestyle factors, such as financial problems (e.g. West, Reed and Gildengorin, 1998) or long-term social and relationship problems are also contributory factors (e.g. Kraaij, Kramers, and Arensman, 1997). Strength of religious faith has been reported as negatively correlated with depression (see Braam et al., 1997).

Also (perhaps unsurprisingly) institutionalised older adults have major depression in much higher proportions: for example, in the USA, rates run at circa 10
per cent (see Blazer, 1993; 1994), compared with the national average of approximately 1 per cent for non-institutionalised older people. Other studies have found higher rates of incidence (e.g. circa 4 per cent – Forsell and Winblad, 1998; Lindesay, Briggs and Murphy, 1989), probably because of differences in samples

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chosen and the diagnostic criteria used. There is also a danger of the depression interacting with the cause (e.g. a person may become depressed because of relationship difficulties, but their depression may in turn make the relationship worse, thereby increasing the depression, and so on).

There is little age difference in responsivity to treatment, with the majority of both younger and older depressed patients recovering (approximately 60 per cent permanently, 20 per cent with a relapse – Kasl-Godley, Gatz and Fiske, 1998; see also Alexopoulos et al., 1996; Burvill, Stampfer and Hall, 1995; Tuma, 1996). However, the outlook on suicides, which typically are preceded by depression, is far less optimistic. With the exception of Poland, the highest suicide rates in all World Health Organisation countries are in the over-seventy-fives (De Leo, 1997). This may come as a surprise to some readers, as a strong impression created by the media is that suicide is a younger person’s death. To some extent this is true – suicide is one of the commonest causes of death in teenagers. However, this is a matter of proportions –
because the death rate amongst teenagers is very low (in industrialised countries at least), the percentage of suicides is striking, but in absolute terms, the figures are far less dramatic (see MacLeod, Williams and Linehan 1992 for USA figures; Lester, Cantor and Leenaars, 1997 for British and Irish statistics, and Gulbinat, 1996 for a global comparison). Furthermore, suicide attempts by older people are more likely to

‘succeed’ than younger adults’ efforts (Conwell, 1997), where there is over a fifty per cent ‘failure’ rate (Cook and Oltjenbruns, 1989). In part this is because of differences in the physical robustness of the age groups, but also because of methods chosen.

Older adults are more likely to select a method which practically guarantees death, such as shooting (see Adamek and Kaplan, 1996a and b) or asphyxiation, whereas younger adults are more likely to choose less certain methods, such as taking an overdose in a place where they are likely to be found by friends or relatives before the drugs can take effect (see Woods, 1999). In part, the method chosen may be a reflection of the reason for the suicide attempt. Older adults are often attempting suicide to escape from a life of pain and suffering. Younger adults may want to change their situation and the suicide attempt is a response to this (see Fremouw, Perezel and Ellis, 1990). However, it will not suffice to say that suicides amongst older people are purely a response to suffering, since there is also a notable racial and sexual difference in suicide rates (though note there are no gender or racial differences in attitudes to suicide – Parker, Cantrell and Demi, 1997). Namely, older women and older black men do not show an increase in suicide in later life (in fact, if anything, there is a decline). The increase in suicide rate is principally due to older white men. The most parsimonious explanation of this phenomenon is that white men are more accus-

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tomed to power and a high standard of living, and a loss of, or a decline in these is too much for some individuals to cope with (e.g. Miller, 1979). For example, Leenaars and Lester (1998) found that in Canada, suicides amongst older people were higher in provinces where there was general affluence, but a higher percentage of older people were on low incomes. However, this is not a full explanation. Other factors have also been identified, such as medical problems and relationship loss (Florio et al., 1997); depression (see Johnston and Walker, 1996); and social isolation (see Draper, 1996). One ingenious study (Salib, 1997) has suggested that suicide amongst the over-sixty-fives of North Cheshire (a relatively affluent area of Northern England) is positively correlated with hours of sunshine and humidity (though see Godber, 1998, for a critique).

Related to depression is bipolar disorder, better known by its original name of manic depression. The disorder is characterised by episodes of depression alternating with episodes of extreme and unrealistic elation and hyperactivity (mania). Cases of patients showing manic behaviour episodes for the first time in later life are rare (see Shulman, 1997), and it is suggested that such behaviour is not ‘true’ bipolar disorder, but may instead be indicative of an organic cause, possibly related to dementia, though the links are as yet tenuous (see Broadhead and Jacoby, 1995).

Anxiety

The term ‘anxiety’, rather like ‘depression’, is something which most people can understand from their own experience. Practically everyone has at some time felt anxious about a situation they have found themselves in. The level of anxiety experienced by a person seeking clinical treatment is far greater than this, and is often identified by the term anxiety disorder. This refers to a long-lasting state of anxiety characterised by symptoms such as extreme restlessness, insomnia, and fatigue, producing distress and impairment of function. It can manifest itself in many forms, including phobias (an irrational or inappropriately high fear of an item or event, such as open spaces, spiders, and so on); generalised anxiety (a perpetual feeling of anxiety, often accompanied by physical symptoms such as sweating, being aware of a pounding pulse, and so on); obsessive-compulsive disorder (a condition in which to relieve anxiety feelings, the patient is compelled to repeat the same act – e.g.

repeatedly washing the hands to remove anxiety- invoking dirt, and so on; see Gupta, Austin and Black’s 1997 case study of a 93- year-old patient); and panic disorder (characterised by repeated panic attacks – sudden attacks of overwhelming apprehension, shortness of breath, feeling of loss of control, and so on). Anxiety is

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relatively rare in older adults in comparison with the younger population (Smyer and Qualls, 1999), but this does not mean it is not a cause for concern, since within any one age group it is one of the commonest mental illnesses (Scogin, 1998), and is often found in tandem with depression (e.g. Flint and Rifat, 1997) and dementia (see Scogin, 1998).

Researchers are generally agreed that about 10 per cent of older adults report some form of anxiety disorder, the majority of these being a phobia (Lindesey, Briggs and Murphy, 1989; Manela, Katona and Livingston, 1996; Scogin, 1998; Woods, 1999). Of the phobias, a commonly reported one is agoraphobia (fear of open spaces), which tends to be conflated with a more specific fear of ‘leaving the house’.

Other commonly reported sources of concern include falling, dying, and social situations (see Woods, 1999). These are undoubtedly sources of anxiety, but one cannot help feeling that calling them ‘phobias’ may be perhaps a little harsh, since they are palpably more rational than more stereotypical phobias. For example, an often-cited paradox is that older people are the least likely victims of crime but the age group which most fears crime. Therefore, does this mean that older people are being illogical in fearing crime or in going out for fear of being mugged? Statistically, the answer to this simplistic interpretation must be ‘yes’. However, as Woods (1999) and others have observed, this statistic applies to crimes overall, and for certain types of misde-meanour, older people are not much less at risk. The most plausible explanation is that a phobia may arise because a heightened level of anxiety ‘fixes’ onto a tangible and rational topic of concern.

Substance abuse

The term refers to the use of either illegal substances or licit substances with an addictive quality (such as alcohol) in excessive quantities to the point where everyday functioning is severely affected. The stereotype of older people militates against an image of them using psychoactive drugs, but in fact they are heavy consumers of (legitimately prescribed) hypnotic (i.e. sleep inducing) and sedative drugs, and misuse of these is the single commonest cause for admission to the casualty department/emergency room of a USA hospital (LaRue, Dessonville and Jarvik, 1985). In many instances, the reason for this is that the ageing body cannot adequately metabolise the drug in question, leading to serious health problems.

However, an appreciable proportion of older adults are taking prescription sedatives and similar, and have become dependent on them (e.g. Gomberg and Zucker, 1998).

The problem is exacerbated by the fact that patients may be unaware of the risks

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associated with many psychoactive drugs, reasoning that if a medical professional has prescribed them, then ‘they must be alright’, and thus, deterioration in, for example, alertness and cognitive abilities is ignored. More obviously damaging is excessive alcohol consumption. Generally, this appears to decline in later life, along with alcohol consumption in general. A macabre thought is that most alcoholic patients will have acquired their condition in early adulthood and only a small proportion will live to later life (see Fillmore et al. , 1998; Leino et al. , 1998), thereby accounting for at least some of these statistics. Studies generally find that older men are more prone to alcohol abuse, older women to prescribed drug abuse (e.g.

Graham et al., 1996), though these results can vary, depending upon the particular culture tested and measurement method used.

Personality disorder

Whilst it has been seen in Chapter 3 that there are a wide variety of personality types which can legitimately be seen as of equal value, there are nonetheless some patterns of behaviour which are sufficiently extreme and at odds with societal norms to cause distress to the patient and/or those whom he or she comes into contact with. It is important to note that these personalities go beyond the bounds of what might be considered ‘eccentric’ but nonetheless tolerable behaviour. The incidence of personality disorder is believed to be low in later life, but there is a danger that clinicians are willing to overlook patterns of behaviour which would be considered unusual in a younger person because of different expectations about how older adults

‘should’ behave. Certainly there is a lower tendency for older adults to be diagnosed as having a personality disorder (Rayburn and Stonecypher, 1996). Amongst the types of personality disorder most commonly described in the British and American literature(see Smyer and Qualls, 1999) are the avoidant (low self-image and avoidant of company) and dependent (over-willingness to let others decide everything). Since these concur with the stereotype of the retiring older person, it is conceivable that they could be falsely identified as ‘normal’ behaviour. Again, Sadavoy (1996) argues that personality disorders could be masked by other behaviours associated with other mental or even physical illnesses. Because of considerations such as these, the true level of personality disorder may be higher than has been supposed (see the meta-review of this subject by Abrams and Horowitz, 1996). However, the level is felt to be particularly high in patients with depression (see Abrams et al., 1998). Note that there are possible cultural differences in the relative frequency of these disorders.

For example, some Croatian researchers report the highest prevalence in their

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country was for sadistic and anti-social disorders in men, and self-defeating, borderline and schizotypal disorders in women (Mandic and Barkic, 1996).

Schizophrenia

The final illness to be considered in this chapter is schizophrenia. The term means

‘cloven mind’ in the sense of a broken or fragmented self, rather than the popular misconception of a ‘split personality’. In essence, it is a profound disorder of thought, perception and language in the absence of mental retardation, characterised by a severe distortion of perception of reality and concomitant changes in emotions and behaviour. There are various forms of the illness, each with a distinct set of symptoms.

The commonest of these symptoms include irrational beliefs about the way the world functions, often with a central theme that the patient is being persecuted. There may also be hallucinations (such as ‘voices in the head’). Language can often be best described as ‘surreal’, with unusual expressions and ideas and invented words (see Stuart-Hamilton, 1999a).

Most commonly, schizophrenia first appears in early adulthood (early onset schizophrenia, or EOS), but about a quarter of cases arise in middle age or later (late onset schizophrenia, or LOS), and some studies have estimated about a tenth of schizophrenic patients first show symptoms in their sixties or older (see e.g.

Bartels and Mueser, 1999; Karon and VandenBos, 1998). Thus, older schizophrenic patients can be divided into EOS and LOS groups, depending upon the length of time they have had the illness. It would be misleading to create the impression that LOS suddenly appears without warning. Studies often report that LOS patients have led fairly reclusive, undemanding lives, with few social contacts. They have typically been protected either consciously or tacitly by parents or friends, and it is often the death or incapacitation of the latter which precipitates the onset of the illness. In other words, LOS may have been an illness waiting to happen.

Straightforward comparisons of these groups are not always easy, however. For example, because EOS patients have received radically different treatments for their illness than LOS patients, there may be a strong cohort effect. Again, the age at which patients are first introduced to antipsychotic drugs appears to have an effect, with older patients reporting significantly more adverse reactions (though these can be ameliorated – see Bartels and Mueser, 1999). There would appear to be little difference in the symptoms found in EOS and LOS (Lacro, Harris and Jeste, 1995; Reicher-Roessler, Loeffler and Munk-Jorgensen, 1997; though see Jeste et al., 1997), although some EOS-LOS differences have been identified in such measures as EEG

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patterns in response to auditory stimuli (Olichney et al., 1998). It has also been noted that a disproportionate number of schizophrenic patients develop dementia or at least dementing symptoms (see Arnold and Trojanowski, 1996). However, after some early histological studies supporting a link, more recent work has failed to find DAT-like atrophy in the brains of older schizophrenic patients (Arnold et al., 1998; Purohit et al., 1998). Notwithstanding these comments, the prognosis for treating patients with either form of the illness is reasonably optimistic (Karon and VandenBos, 1998).

Overview

It should be recalled that mental illness in older adults is often lower than for the population as a whole. The problems faced by older patients can of course be grave, but in many instances, evidence points to these not being appreciably worse in themselves than those faced by younger patients with the same illnesses. Of course, contracting a mental illness in later life does not absolve the patient from becoming ill with common age-related physical complaints such as arthritis or hearing impairment, and of course it may be anticipated that these will exacerbate the problem (see e.g. Smyer and Qualls, 1999).

Recommended reading

Several books can be warmly recommended. An excellent general overview of ageing and mental health is provided in a book chapter by Woods (1999) and on a larger scale, Smyer and Qualls (1999) and Nordhus et al. (1998). Lezak’s Neuropsychological Assessment (Lezak, 1995) is a vast and comprehensive review of its subject, and includes an excellent section on the dementias. Parkes, Zec and Wilson (1993) is an edited volume of papers on the neuropsychology of the dementias. Like Lezak, it is a specialist work and has a high concentration of technical terms. Stuart-Hamilton (1999a) provides an overview of mental illnesses, their classification and treatment.

chapter 7

Problems in Measuring
the Psychological Status
of Older People

Introduction

The chapters so far have attempted to present the psychology of ageing as a narrative, representing, as far as possible, a consensus view of the discipline. This is a general introduction to the topic, and it would be unfair to present a more critical view of the literature as the ‘correct’ one to students discovering psychogerontology for the first time. However, it is perhaps unrealistic to expect students to accept that findings reported are without criticism, or that the research is so cut and dried that any future discoveries can only be footnotes on what has already been written. In this chapter, some criticisms of existing methodologies are offered. However, note that what follows is one view, and others are possible.

The view from without

Simone de Beauvoir divided her classic study Old Age (de Beauvoir, 1970) into two main sections: one was the view from without, and the other the view within later life. This book has taken the view from without for the simple reason that research on ageing is almost solely the work of young, or at least pre-retired adults. The simple and pragmatic reason for this is that most published research is the work of paid academics who almost always are aged under sixty. At times, an unfortunate impression is created by this. Researchers sensibly need to take a detached view of their subject matter, but by discussing age-related phenomena in a dispassionate way, 195

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there are times when the person appears to have been lost from the discussion. A reading of any of the major psychology of ageing journals creates an impression that ageing is nothing more than a testing ground for how senescence or dementia affects models of memory, intelligence, personality, or caregiver stress. The concept that the subject is about studying real people in real life situations is conspicuously absent.

However, the criticism really only stands if one is prepared to accept a rather naive view of research. Practically any academic topic at the level of individual journal papers can appear divorced from reality. Individual pieces of research should be seen on their own merits, nothing more. It is up to commentators and the individual reader to decide what these findings mean when taken as a whole.

However, if the field of the psychology of ageing is viewed at a broad level, it creates a curious picture. It can be readily demonstrated that later life is, on the whole, a time of decline. It can also be shown that there are so many caveats to this summary that it is difficult if not impossible to make a definitive statement about a typical older person. It is quite possible that this is the correct summation of the field. Social sciences study individuals and by definition, this means accepting greater variability than in, say, the physical sciences. Making a statement about the properties of a typical older adult means accepting that the said person will come equipped with a wide range of options. In comparison, a test tube of mercury is the same the world over.

However, an acknowledgement that ‘people are different’ does not absolve a researcher from making as accurate an assessment as possible. Perhaps part of the reason for the general woolliness of findings is that experimental protocols and philosophies have not been accurately pinned down in the first place. In the rest of the chapter, some of the potential flaws in current experimental practices will be examined. For the sake of simplicity, this will be done principally with reference to a single topic within the psychology of ageing; namely, intellectual skills.

Confounding variables and the search for ‘pure’ ageing Research on ageing is predicated on the assumption that we can measure something called ‘pure’ ageing. This is not always explicitly stated by researchers, but it is at least a tacit assumption. It is essentially the belief that after cohort effects have been accounted for, any age difference which is left ‘must’ be due to ageing alone. In Chapter 2, it was noted that to a certain extent, age differences on fluid and crystallised intelligence tests depend upon the test methods used. Fluid intelligence test performance, for example, is partly governed by the speed at which a person can write down their answers. Older people, because of arthritis, rheumatism, and similar

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conditions, generally write less quickly, and this can affect how many answers they can produce in a paper and pencil test against the clock. In short, test artefacts may be underestimating the true mental state of an older person. Conversely, the absence of age differences in crystallised tests may be due to the reverse reason - namely, that tests are generally untimed, and that were time limits imposed, an age difference would display itself.

Writing speed and issues about whether a test should be timed or not are far from the only issues shaping age differences. Simply reading from the first pile of journal abstracts to hand on the author’s desk, the following potential confounding variables may be identified: level of education (Anstey, Sankov and Lord, 1993; Christensen, Hendersen, et al., 1997; Christensen, Korten, et al., 1997; Compton, Bachman, and Logan, 1997); general health (Horn, 1982; Riegel and Riegel, 1972); level of exercise (Powell, 1974); level of motivation (Bauer, 1966); degree to which skills are practised (Charness, 1979; 1981; Milne, 1956; Plemons, Willis and Baltes, 1978) sensory functioning (Lindenberger and Baltes, 1994); and socio-economic status (Rudinger and Lantermann, 1980). The above list is just the tip of the iceberg: a very long list of possible confounding variables can be devised by a person with the time and will to do it. Note that it is not necessary that all of these items are of equal importance, but the sheer magnitude of the list makes it likely that a significant proportion of the difference between older and younger adults may be due to cohort effects rather than ‘pure’ ageing.

Salthouse (1991b), in a meta-analysis of the ageing literature, found that removing health or education level lessened, but did not remove age differences. However, with the greatest respect to Salthouse, who is a scrupulous researcher, these are just two variables from a potential list of hundreds. What if instead of two variables, a larger number were chosen? In theory, we could decide to measure what is left of an age difference after 5, 10, 20 or 100 confounding variables are accounted for. There is no ‘law’ to stop researchers doing this. We could, for example, continue to add in more confounding variables until an age difference completely disappeared. Statistically speaking, this would be a dubious practice, but the point is that we really have no clear grounds for knowing what constitutes a valid cohort effect which should be accounted for, and what constitutes an invalid one. Consider the following example.

Suppose that it is decided to control for effects of cardiovascular disease, since it is plausible that people with heart and circulation problems may perform less well on intellectual tasks. Thus, patients with these conditions are excluded from the experiment. However, why stick at cardiovascular problems? Why not also exclude people with arthritis, or rheumatism, or cancer? All these conditions could plausibly influ-

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ence intellectual performance. Taking this policy to extremes, one would finish with a sample solely consisting of A1 fit older adults. This may satisfy the criteria to exclude any illness-based cohort effects, but it would be hopelessly unrepresentative of the older population (see Stuart-Hamilton, 1995). And this is solely considering health. What if we now also decide to balance older and younger adults on education levels? Older adults generally received fewer years education. Therefore, this should be controlled for. However, how do we now control for differences in the type of education received? Older adults tended to receive rather more rigid forms of teaching with greater emphasis on rote learning, and many older adults (in the UK at least) received greater training in practical skills, such as needlework and woodwork, than younger people. How is this controlled for?

Clearly it is impossible to control for all possible confounding variables. Inevitably, some will have to be left in the analysis, and they will inevitably contaminate the data to a greater or lesser extent. As can be seen by a perusal of gerontology journals, many researchers do not even bother to start correcting for possible cohort effects, others only control for one or two. This might not matter if all researchers drew their volunteers from the same group of people, since in that case, comparisons between experiments would be based upon a common ground. However, the people upon whom the tests are conducted vary enormously. To take an example of this, the author chose a single edition of a recent ageing journal and recorded the way in which volunteers were recruited for studies of non-dementing ageing. Two of the papers gave insufficient details, but the remainder listed the following: newspaper advertisements in New York; newspaper adverts in Canada, plus ‘various community organisations’; advertisements in the media; advertisement in senior centres and senior apartment complexes; members of an older volunteer pool maintained by the university in question; people originally recruited in a 1960s national survey; local volunteer groups; a sample of those aged over 70 on the electoral roll in part of Australia; and healthy community resident volunteers. The level of screening for other conditions (particularly health, which was often left to self-report) was extremely variable, from a rigorous exclusion of anyone not A1 fit to no real barriers to participation. It takes little contemplation to realise that the list of participants in the above studies could potentially be enormously different. Some studies will have physically healthier participants than others, some will have people from higher socio-economic groupings, and so forth.

It might be argued that the above argument is unnecessarily pedantic. However, as has been demonstrated throughout the previous chapters, variability increases considerably in later life, and any practices which are enhancing this variability and

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blocking sensible direct comparisons between studies are doing little to clear the picture. Added to this is the further problem that when younger adults are included for comparison purposes, studies nearly always use students recruited from undergraduate participation pools. Given that older people are almost certainly being recruited from a much broader intellectual base (i.e. the undergraduates are almost bound to be smarter on average, since not all of the older participants will have studied for a degree), and will have different motivations for participating (e.g. the desire to participate in research as opposed to doing a boring task in order to get a degree), any comparisons between older and younger adults are coloured right from the start.

Given such criticisms, it is readily apparent that any experiment on older adults is bound to contain at least some cohort effects. However, something might be done to control at least the most striking cohort effects. This would involve establishing a benchmark measure of controls, which all researchers would agree to abide by (similar controls exist in other sciences to great effect). This would consist of controlling for at least the most often-cited variables (education, general health, etc), recruiting participants in a set manner (i.e. everyone agrees to recruit in the same way), and pragmatically accepting that inevitably some confounding variables will be left, so that some ‘noise’ will remain in the data. Regrettably, there is no ‘industry standard’

set of such variables which all researchers are expected to use (Stuart-Hamilton, 1995). Thus, different researchers are left free to have different policies, as has been seen, and this makes judgements about the true size of age differences very difficult to determine (Stuart-Hamilton, 1995; 1999b).

The above argument is predicated on the assumption that a measure of ‘pure’ ageing is submerged beneath the cohort effects, and furthermore, that this measure is useful. However, this is debatable, and the following counter-argument might be proposed. A measure of ‘pure’ ageing is often tacitly assumed, but rarely explicitly explored. However, since cohort effects are removed by researchers in order to get a

‘more accurate’ view of ageing, it may be assumed be assumed that ‘pure ageing’ is a measure of ageing which is free of the influences of upbringing. In short, this is the nature-nurture debate, so beloved of individual differences researchers, being played out on a new field: pure ageing is nature, cohort effects are nurture (Stuart-Hamilton, 1999a). However, it is difficult if not impossible to see how intellectual development could occur if it were totally free of influences of upbringing and social interaction: in extremis, it is like arguing that only a person raised in an isolation tank can experience pure ageing. Most intellectual skills shown in later life occur because of these, not in spite of them (see Pratt and Norris, 1994). Cohort effects may thus be more than just an inconvenience which distorts the ‘true’ results - they could be part and parcel of an

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older person’s intellect to the extent that they cannot be removed without denying part of that person’s intellectual status. It may thus be argued that each age cohort is inevitably different, and if part of the difference is due to differences in upbringing, then so be it.

Neither of these views - ‘all cohort effects are bad’ versus ‘cohort effects are ageing’ is in itself satisfactory. However, finding a compromise between the two is fraught with difficulties as well. This would involve finding a limited set of cohort effects which would be controlled for, but, as has already been seen, defining this in itself is a daunting and perhaps impossible task. We are thus left with only one certain statement: older people tend to be worse at intelligence tests. However, the degree to which this is a reflection of ‘pure’ ageing is left open for debate – as is what we mean by ‘true’ ageing.

The relevance of findings to everyday life

A further problem for ageing research is that it often is at odds with everyday life.

Throughout this book, psychological tests (and intelligence tests in particular) have been presented as if they were ‘pure’ measures of intellectual skills. If this is so, then one would logically expect psychological tests to correlate well with abilities at

‘everyday’ skills. For example, intelligence test scores should be excellent predictors of scholastic ability, job status, ability at chosen job, and so on. However, this is not the case. An old psychological chestnut is that the best correlation ever found between IQ and a real life measure was 0.7. The real life measure was the number of real (as opposed to false) teeth possessed by the participants. Usually, IQ tests are poor predictors of real life performance – correlations are usually of the order of 0.2–0.3: in other words, about 10 per cent of the variance on the real life measure is predicted by IQ. This is not to say that intelligence tests are useless. Even their detractors acknowledge that they are good at identifying extremes of ability. Thus, IQ tests can identify the exceptionally intellectually gifted and deprived (though it can also be argued that one really does not need an IQ test to do this). What intelligence tests cannot do with any real accuracy is identify performance of people between the extremes (i.e. the majority). This raises an uncomfortable question for psychogerontology: if intelligence tests are not an accurate reflection of everyday skills, then of what value is the bulk of work on ageing intellectual changes?

Salthouse (see Chapter 2) provides one answer to this question: namely, that although intelligence is a poor predictor of absolute ability, it is vital as a control process. This may be so, but one might wonder why psychologists have indulged in so

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much research on measures which have at best only a minor relevance to everyday life. An uncharitable view might be that although IQ tests are poor predictors, they are still the best measure available, and thus they continue to be used, until, to quote the song, ‘the real thing comes along’. By this reckoning , the psychology of ageing is very well versed in what happens to 10 per cent of older people’s intelligence, but, like the iceberg, 90 per cent of it remains hidden. This is too severe a judgement, however. At a general level, IQ tests are probably perfectly adequate indicators of intellectual change. Throughout this book, it can be seen that changes in specific memory, linguistic and intellectual skills are correlated with a decline in intelligence test performance. Admittedly, the correlations have often been small, but nonetheless they are statistically significant and have fallen in the expected direction. For example, there have been no instances where overall the older people have got higher fluid intelligence scores than younger participants, or where memory has improved the lower the intelligence test score of the participant. IQ tests are quite adequate, indeed they are remarkably consistent, at predicting trends.

It would be unfair to blame psychogerontology for this failure to find the IQ test of more than general descriptive use. The problem is one which has beset psychometrics (the study of psychological differences) since its inception. What is at stake is convenience. In an ideal psychometric world, participants could take a single IQ test, and this score would perfectly predict their ability on any intellectual task they could ever encounter. A single test score would thus tell one all one needed to know about a person’s intellectual abilities. Unfortunately for psychometricians, this test does not exist, and it is virtually impossible that one could ever be devised. The reason for this is that psychological research has shown that intellectual skills are not determined by a single factor, but rather by several intellectual skills, each of which is at least partly autonomous of the others. The general intelligence test is really only an expression of the aggregate of performance on all these sub-skills, and hence can only hope to give an overall impression of an individual’s abilities.

The situation is akin to predicting the performance of a football team. A team consists of different players with different specialist abilities. A league table gives an overall gauge of how good a particular team is, by showing its position relative to other teams. However, league position tells one little about the abilities of individual players in the team. Of course, good teams will tend to have better players than bad teams, but this is not an inevitable rule. For example, a particular side might have the best forward in the history of the game, but the side may be languishing at the bottom of the league table because the rest of the team is poor. In a similar manner, the overall score on an IQ test can give an indication of the overall intellectual perfor-

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mance of an individual, but it cannot accurately predict how well a person will perform a specific task. Nor can it be said that measures of sub-skills are necessarily more informative. There is a double bind in psychometrics which is as follows. General intelligence measures are poor predictors of everyday skills. Measures of sub-skills give better predictions, because they assess abilities which are more akin to those used in ‘real life’. However, there is a danger that the tests of sub-skills may be so like real-life problems that one might as well cut out the middle man and use the real life ability as a measure. Thus, at one extreme a measure fails because it is too general, whilst at the other it flounders because it is too specific.

A further criticism of lack of realism comes from the observation made in Chapter 2, that the difference between younger and older adults on many intelligence tests amounts to nearly two standard deviations. Readers with a background in education research will recognise this as a very meaningful figure, since in the case of children, performing at 2 standard deviations below average would mark a child down as potentially in need of remedial (or ‘special’) education. If the way older people perform on intelligence tests is genuinely indicative of the way they behave in everyday life, then a large proportion of older adults should be on a par or worse than younger adults or children unfortunate enough to fall within the ‘special needs’ bracket.

Clearly this is not the case. In other words, a simple reading of psychological tests underestimates older people’s ‘real life’ skills.

Indeed, psychogerontologists seem tacitly to acknowledge this with practically every paper they publish. Researchers are rightly concerned about any reports on racial differences which imply a ‘genuine’ difference between races. However, even the largest differences between racial groups ever reported pale into insignificance next to the findings of a large number of studies of ageing. Report after report catalogues declines which should mark down an average older person as barely capable of functioning without remedial help, and yet scarcely a comment on the practical implications of what has been found is made. It is as if psychogerontologists find age-related declines, but do not want them to matter.

The above is of course a rather exaggerated argument; at the very least, declines in skills may be compensated for by other strategies or the skills may be ones which older people do not use very much in everyday life. However, if that is the case, then why study skills which may be important to younger adults but which have little relevance to older people? In part the answer is that it is important to map out mental changes using these measures because they give a good indication of the extent to which some skills alter or decline. One cannot judge if an older person is compensating unless it is known what he or she is compensating for. However, it is also arguable

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that many intellectual skills are studied because of tacit assumptions made by academics about ideal ageing and ideal intellectual life. Academics have a tendency to judge events by their own standards, and to expect others to do the same. Thus, we are sporadically treated to polemics from commentators arguing that people lack the skills taught by their discipline. Thus, representatives of the arts argue that people are insensitive to aesthetics in a mechanistic world, whilst scientists counter-argue that too much time is spent on teaching ‘easy’ artistic subjects, and as a result, the general public is typically illogical and lacks the necessary knowledge about scientific matters to make informed decisions. It is neither necessary nor timely to enter further into this debate here. However, the general issue makes it apparent that academics have an established interest in the types of learning and knowledge people should acquire, and this inevitably contains a value judgement that some forms of knowledge are better than others.

All of which leads back to the psychology of ageing. The measures of intellectual skills which psychogerontologists use are typically not developed just for studying older people. Generally, they have already been devised for testing younger adults and then are simply given to older people to see how they perform relative to this younger age group. In other words, intellectual ageing is being set up as a measure of how far older people have fallen from the ideal standard set by younger adults. In other words, ‘successful ageing’ in most psychogerontologists’ eyes is the degree to which an older adult maintains the same level of performance he or she had in younger days (Stuart-Hamilton, 1999b). Thus, it is assumed that older people should not develop as much as remain in a kind of mental stasis once they hit their intellectual peak in the late teens or early twenties. Although some commentators note that older adults may attain greater depths of wisdom or become more adept at integrating pragmatic considerations with pure logic, matters are still largely couched in terms of the degree to which decay from a youthful ideal is either accelerated or diminished.

However, this begs a rather obvious, if contentious question. Why should later life be seen negatively if one does not analyse things as analytically or know as much as a youthful ideal? Such things matter to academics, but not everyone would consider it a disaster if one day their verbal skills had declined from a previous level and they could no longer spell charisma or liaison, or remember what manumit means. The pursuit of high intellectual ideals is very important to some people, academics included, but they are not necessary nor desirable for everyone. The days of most older people are not filled with reading books favourably reviewed in one of the more highbrow newspapers, watching subtitled films, or doing The Times crossword. To assume that a high intellect, or rather a particular set of intellectual skills, is a necessary

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part of life, is both patronising and divisive. Indeed, the goal of an intellectually-powered old age bears little resemblance to anyone’s ideal beyond that of university lecturers contemplating what they will do in retirement. To assume that this should be set as the goal by which all older people must be judged is foolhardy, to say the least. We have seen that psychogerontology has structured views of ageing in terms of how the older mind differs from the younger. It is assumed that both age groups perform tasks using the same set of mental skills. To take an analogy, the older and younger people are akin to two soccer teams made to compete against each other. However, what if one of the teams has given up soccer and gone off to play bowls instead? In other words, psychogerontology’s view of intellectual changes is predicated on the view that older adults are still using the same set of intellectual skills that younger adults use. However, the evidence for this, as has been seen, is far from compelling.

This has been demonstrated by the studies of older adults performance on traditional measures of child development, such as Piaget’s experiments. If older adults are rejecting these skills, and this may in part be linked to choice of lifestyle or motivation, then it is difficult to continue comparing older and younger adults by the same rigid criteria. However, this still leaves the necessity of explaining how the shift in mental styles occurs. The following is one possible explanation. We begin with the premise that development consists of the accumulation of knowledge and problem-solving strategies, determined by both genetic inheritance and the environment in which one lives (none of this should be contentious). The knowledge and problem-solving strategies can (with tongue again only slightly in cheek) be described as

‘idea species’. Whether an idea species thrives depends upon the conditions in which it finds itself. Species will only be acquired if the person can integrate them into an existing mental framework, and they will only be maintained if effectively stored and rehearsed. Thus, acquisition of skills in childhood and their loss in later life are governed by the same basic mechanism. Existing psychogerontological models map cross-sections of processes at one point in time – they add a depth to the model whilst developmental studies add breadth. Much of this has been voiced in one way or another before. The key difference is that in the past it has been tacitly assumed that development and ageing were essentially directed towards specific goals. Arguably this ultimately replays the homunculus problem which plagued computer modelling studies for years. The difference here is that the whole process is essentially blind –
the individual has no truly conscious awareness of these processes, and whether a mental process is gained or lost is ultimately down to probabilistic odds. We can stack the odds in particular directions through planning, but essentially the process is re-

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moved from the concerns of current studies which tacitly assume a single desirable path of development.

Unwitting ageism

The above argument creates a case for arguing that ageing is essentially what a person makes it, and that defining it in simple terms of being worse or better at tests is rather missing the point. Many researchers, even if they disagree with the model presented, would probably concur with this conclusion. However, it is still very easy to create an artificial barrier between age groups even armed with an egalitarian philosophy. This raises the topic of ageism (an irrational prejudice against older adults and/or ageing). Deliberate ageism is a vile condition and unusually stupid even by the low standards of other prejudices. A racist may be a vile piece of pond slime, a male chauvinist a disgrace to as noble a creature as the pig, but both can attack their objects of hate in the sound knowledge that they will never change race or sex. An ageist person, on the other hand, has a high chance of turning into that which they hate –
namely, they will themselves grow old. Thankfully, few ageist people take careers in caring for, or researching into, older adults. Even so, gerontology is not free of all ageist philosophies.

It is not ageist to say that older adults are more prone to physical ailments than younger people; that they are more likely to get dementia; or that they are generally less able at intelligence tests. It is likewise not sexist to say that on average women are shorter than men, that they on average cannot lift weights as heavy, or run as quickly.

However, if these measures are taken as value judgements rather than simple statements of average difference on measures of dubious importance, then this paves the way towards viewing one group as intrinsically inferior to another. This can be done for the most egalitarian of motives. For example, it might begin with a laudable general declaration that older adults need greater care because on average, they have greater needs. It is a short step from this to regarding older people as automatically being weaker and less adept on a wide range of measures. A person holding these views can still be doing so for the very best of reasons, but a stigma is being created.

For example, consider the following statement in an instructional video for nurses concerning sexual abuse of patients. The presenter reports that there have been cases of older patients being sexually abused, demonstrating that ‘even the elderly are not immune from attack’. At one level this of course raises a very proper level of concern; sexual abuse is a very serious matter. However, the phrase ‘even the elderly’ carries a striking value judgement that older people are enfeebled and sexually unattractive: a

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strong piece of stereotyping which has arisen from what was undoubtedly a genuine and laudable concern.

chapter 8

What is the Future of Ageing?

Introduction

In this final brief chapter, the ways in which older adults will react to and behave within a future, more technologically-driven society will be considered. This will be done by bringing to bear arguments and information described in earlier chapters.

What will constitute being ‘old’?

At the current time, judgements about what makes a person ‘old’ are based on several criteria, including appearance, attitudes, and amount of leisure time. However, a variety of developments is likely to change all of these in the future. Appearance may well be the most fundamental factor to be affected. Already, plastic surgery and hormone replacement therapy can remove a decade or more from a person’s appearance. These are of course largely cosmetic changes. There is little reason to doubt that techniques in this field will improve and possibly become more affordable, so that a wider range of people can make use of them. This is aside from the possibility that advance in medical services may find further ways of retarding the ageing process. It is already well established that some animals can live much longer by simple manipulations of their environment and diet. The leap from this to humans is not a simple one, but at some point the change will almost certainly come, and the over-sixties will no longer look ‘old’ in the stereotypical meaning of the term.

However, will this necessarily change matters? Might it not be the case that people will look for different indicators of age, so that instead of looking for wrinkles or greying hair, attention shifts to, for example, the brightness of the eye? It can be demonstrated that cultures differ in their perception of key physical attributes in other respects, such as erogenous zones. Heterosexual males of different cultures 207

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might be most attracted by breasts, buttocks, legs, or the nape of the neck. Why should the prime indicator of age not similarly shift across cultures separated by time?

Alternatively, ageing retardation may be very successful, so that no-one can tell how old an adult is. This raises a series of possible dilemmas. Will some individuals deliberately select to grow older ‘naturally’ and choose to make themselves outcasts?

Perhaps anti-ageing treatments may be very expensive, so that only particular social castes can afford them. Again, perhaps a new neurosis will arise, afflicting people who feel ‘trapped’ in a body which is the wrong age for their thoughts and attitudes.

Perhaps treatments might delay the onset of signs of ageing, but nonetheless it will eventually arrive (i.e. at the point when the treatment ‘fails’), albeit at a later age.

Might this physical change (which the individual has taken deliberate steps to avoid) be more traumatic than for a person who has aged naturally and passively allowed his or her body to undergo the ageing process? Before voting too hastily in favour of anti-ageing treatments, it would be wise to consider the potentially serious psychological consequences. It should also be noted that whatever the outcome, images of ageing are still likely to be predicated on the assumption that the process is synonymous with physical decline. Warren (1998), in an interesting review of the history of identifying markers of ageing, identifies this as the prime marker of the ageing process in the future.

Attitudes are supposedly a good indicator of age. The popular conception of the older person is that he or she is conservative and cantankerous – a thoroughly erroneous view, as was noted in Chapter 5. However, there is a further reason for doubting this assumption. There has been a radical sociological shift in the past 50 years towards a far more liberal and permissive society, which has allowed young adults to express and celebrate being young, rather than attempting to become carbon copies of their parents’ generation as quickly as possible. The first rock ‘n’ roll generation has now reached retirement age, and the flower power generation is in its fifties. The full ramifications of this are complex and more properly dealt with by a sociological text, but an important psychological prediction emerges from this. Namely, that older people of the future are unlikely to fit into the niches which have been established by societal expectations with quite the same willingness as previous cohorts. They have seen that conventions can be flouted and that protest can work. Accordingly, if younger generations do not change societal mores to better cater for older people, then older people are more likely to do it themselves.

A final consideration concerns leisure time. Perversely, in industrial societies where leisure is treasured, an excess of it is usually greeted with distaste, since it often

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indicates unemployment or retirement. However, the increased automation of work (particularly computerisation) may well change this attitude. Shorter working weeks, and an increase in flexihours and home offices may lead to more people of working age spending a greater proportion of time in their homes than in traditional workplaces. This means that retired and older people may no longer be marked out simply because they are not ‘at work’.

Older people and the technological society

It is a cliché to note the immense changes in lifestyles of people in industrialised nations which have resulted from the technological and scientific advances of the past hundred or so years. It is tempting to imagine that older people will be swept up in this tidal wave of changes, and this raises the issue of how well they will cope.

Intuitively, one might suppose that the greatest impact will be in improved medical care, and that people will live longer because of this. However, as was noted in Chapter 1, this is not necessarily so. The increase in the average life expectancy has primarily resulted from fewer people dying in infancy rather than a lengthening life expectancy per se. Indeed, the older the age group considered, the less the increase in life which modern medicine can provide. Many of the illnesses which afflict older adults, such as cancers and cardiovascular complaints are as incurable now as they were in 1900 (though modern palliative care can certainly alleviate the suffering more efficiently and may be able to prolong life expectancy slightly further). Again, if a cure for a disease is found, this need not prolong life by a significant degree. Finding a cure for one form of cancer, for example, does not cure all the other varieties.

Furthermore, curing an older person of one illness does not necessarily improve their life expectancy to a significant degree. As has already been noted, older adults (particularly those aged over 75) may have several physical symptoms on the verge of col-lapse. Preventing a disease striking one of these down does not make the others any less immune to degradation. In short, curing a fatal heart disease may simply make a failing liver the cause of death instead (please note this is not an argument in favour of denying older adults medical care because it is a ‘lost cause’; although it may apply to a proportion of older adults, it is not a universal truth).

Because of these considerations, it is unlikely that people aged 70 or over are likely to display an appreciable rise in life expectancy in the future. This is simply because although cures for individual illnesses may be found, methods of overcoming widespread ageing decline will have to be discovered before much benefit can be reaped. This raises a further, more controversial issue – will there be the impetus to pursue this? The financial burden imposed by the greying population was noted in

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Chapter 1. Any appreciable lengthening of the lifespan will simply compound this problem. There is also a moral issue – if a method is found to prolong life, it carries with it the question of whether the quality of life makes the effort worthwhile. In addition, the procedure may be hazardous – current medical thinking assumes that, for example, lengthening telomeres may also increase the risk of contracting cancer (see Concar, 1996). What if a person considers the prospect of an artificially longer life and decides, for whatever reason, that they do not want it. Will this refusal be counted as voluntary euthanasia? Again, what if the treatment is expensive and thus only within the reach of the very wealthy. Should they be allowed to enjoy extra life just because they have more money? Mercifully, such questions can for the foresee-able future remain the preserve of science fiction writers (e.g. John Wyndham’s (1960) excellent The Trouble With Lichen), as the imminent advent of truly effective life-prolonging drugs seems unlikely.

Another major impact of technological change is the automation of tasks. It is a commonplace of science fiction to envisage a time when manual tasks have become the preserve of machines, and the marked decline in manual labour as a proportion of the workforce is testament to this. However, the advent of word processors, copiers, and so forth has also seen a decline in ‘white collar’ occupations (copy typists, to give one example). These changes are not likely to be limited to relative routine occupations. The use of ‘expert systems’ which seek to emulate the diagnostic abilities of a specialist, is also likely to come to the fore. Large investment and banking firms already use computers to monitor changes in stock market prices, and can automatically initiate the buying and selling of shares, as witnessed by the popularity of tracker accounts. In the future, it may be possible to consult a computerised doctor, which will perform the same role as a general practitioner by analysing the patient’s responses to a series of questions, using algorithms based on the diagnostic processes of a real doctor. The impact of automation is almost certain to affect the lives of future cohorts of older people. One of the most basic issues (and one already touched upon) concerns shifts in working practices. There will undoubtedly be changes in the socio-economic backgrounds of retired persons. As noted in Chapter 5, social class and occupation type are predictive of attitudes towards later life, and accordingly, there may be a shift in the pattern of behaviour and lifestyle in the older population as a whole.

However, any consideration of future trends based on technological innovation is inevitably highly speculative, and a perusal of future predictions in 1960s textbooks provides a suitable warning. In the sixties, there were authoritative predictions that by the 1990s, everyone would either have died from pollution, nuclear war, famine

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and/or overpopulation. Alternatively, everyone would be living a life of luxury, with every whim catered for by robots. It is highly probable that the predictions made here will be similarly ludicrous. Humanity has a strange habit of finding more work when old employment opportunities are replaced by automation.

Of greater interest to the psychologist are the likely direct effects of technology on older people. The effects of this can be somewhat anticipated from the impact of previous technological innovations. The by now almost ubiquitous telephone, television and radio allow older people access to an outside world which would have been unthinkable for all but the very wealthy 50 years ago. In shaping leisure activities, the impact of television on modern life is difficult to underestimate. Besides being entertaining, television enables older people to see places, plays, concerts and other cultural events which they perhaps are no longer physically or financially robust enough to attend in person. Often older people (especially those living alone) report using the television or radio as a comforting background noise without especially attend-ing to the programme. However, there are disadvantages as well. The programmes on television and radio are primarily geared to the needs and demands of younger adults. Programmes may be either presented in a manner too lurid for an older person’s tastes, or possibly even the basic content may be unappealing (e.g.

‘youth’-oriented programmes). The advent of ‘niche television’ afforded by the multi-channel delights of satellite and cable television has not yielded much which could be said to be of especial interest to older adults. Certainly there is no channel dedicated to older people (though there are tens of channels specifically for children and a certain kind of ‘lobotomised’ teenager), and few programmes of special interest, other than an occasional worthy (and usually rather dull) magazine programme by a community television unit filling up the off-peak hours. The majority of programming is aimed solidly at younger audiences. However, older people are generally the heaviest consumers of television programmes, a finding echoed across different countries (e.g. Dubois, 1997; Grajczyk and Zoellner, 1998). Perhaps (as was suggested in the first edition of this book more than nine years ago) there will eventually be an outlet for smaller, community-led television stations which will allow air time for a significant proportion of programmes by and for older viewers, but as yet there is no real evidence of this outside a few pockets of activity in the USA, where it appears to have met with some success (Burns, 1988). Printed outlets for older adults, such as magazines, have met with greater success, and several specialist publications are commercially successful. However, these can be seen as appealing to a particular niche within the older community, such as the affluent middle classes interested in expensive holidays and investment advice (see Featherstone and

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Wernicke, 1997). For a variety of demographic and socio-economic reasons, a publication with wider appeal is unlikely to be a viable commercial proposition.

There may be similar demographic limits to the degree older adults use the Internet. The medium should hold especial benefits to many older people. For example, there is a vast range of information available; there are opportunities to join discussion groups; there is not the feeling of being ‘rushed’ which there may be in an oral discussion, and all without needing to leave the safety and comfort of one’s house. Use of this medium is currently more common in the USA than in many other countries, particularly Europe, in part because of greater relative affluence, but also perhaps because of considerable differences in phone-call costs. Reflecting this, there are considerable national differences in the degree to which older adults use the

‘Net’. A few minutes use of a search engine reveals that whilst there is a plethora of specialist sites run by older adults for older adults in the States, there are a handful in mainland Europe and practically none in Britain. Whilst there has been considerable impetus to encourage older Americans to use the Web, in part through the generally greater awareness of ageing-related issues, plus the generosity of ventures such as the MicrosoftSenior Initiative (http://www.microsoft.com/seniors/), efforts elsewhere have often been patchy. Even within America, at the time of writing, computer ownership amongst older people is under half the national average. In part, older people may be deterred from using a computer through feelings of lack of control, dehumanisation (Czaja and Sharit, 1998) and anxiety, though this may be unrelated to real computing ability (Laguna and Babcock, 1997). The degree to which people succeed during their initial training also plays a key role in determining future participation in computing (Kelley et al., 1999). In addition, cost may be a key factor.

For all their relative decline in price, in Britain a computer with any real processing speed suitable for Internet use is still a relatively expensive item, and the phone bills incurred are far from cheap. Many older people who wish to participate may be deterred by price. Others may perceive that there is little of interest to them. Lurid media reports of prosecutions of individuals possessing child pornography downloaded from the ‘Net does little to enhance the image that surfing the Web is a suitable activity for a respectable older person. Time will of course tell, but it is possible that Internet use amongst older adults will not become commonplace until either it becomes considerably cheaper, or until sufficient younger ‘Net users reach retirement age.

Other technological changes might also bring mixed blessings. Modern household appliances take much of the strain out of cooking and general housework.

These items are financially available to most if not all older people, and undoubtedly

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are immensely advantageous. For example, refrigeration and better methods of preserving food reduce the risk of food poisoning when an older person’s senses become blunted to the point where they cannot detect something which has ‘gone off’. Furthermore, the imminent arrival of ‘smart’ fridges (which will read bar codes on pre-wrapped foods and warn when something is unsafe to eat) will further enhance this. Simultaneously, labour- saving devices and safety checks may encourage some older adults to avoid exercise and become too complacent. Thus, their health may decline through lack of physical activity and a misplaced optimism in food safety may lead to poisoning.

Other technological changes may still be prone to misuse. For example, use of microchip-controlled medicine dispensers have been mooted (see Kapur, 1995). The time at which some drugs are taken is vital for their efficacy, and because some older people are forgetful, the automated dispenser emits a beep when it is time for the patient to take the next dose. There is of course one minor snag with this device, which is that it relies upon a forgetful person remembering to keep the dispenser within earshot and to remember what to do when the device goes beep. This is a problem which pervades most of the gadgetry designed to help mentally disadvantaged people – they have to remember to use it. Aides-memoires, be they beeping pillboxes, palm-held computers or electronic diaries, clearly fall foul of this problem. The problems created by a declining memory show the magnitude of the problem facing designers. Other technological innovations do not face these problems, and seem at first sight to be quite benevolent, such as the expert systems described earlier. However, expert systems require a computer, and where will the computer be located? We have noted above that computer use may be limited amongst older adults. If an older person has had to make the effort to travel to somewhere where there is a computer (e.g. the doctor’s surgery in the case of a medical expert system), then they will surely want to see a real person as a reward for their efforts. Assuming there is a computer and a doctor program in the house, there are still problems. An expert system only works as well as the information it is fed.

What if people choose to lie or gloss over some symptoms? A human doctor, by observing voice tone and body language, should be better at detecting subterfuge than a computer, unless both hardware and software improve considerably beyond their present limits. In short, the system is open to serious, and potentially fatal, abuse.

A further consideration is that new technology is largely designed for younger adults. Miniaturised electronic gadgets are no doubt a tribute to the designer’s art, but they are often too small for an older person to see or handle efficiently. In Chapter 1,

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it was noted that the ageing perceptual system loses its ability to process fine detail in any sensory modality, and it thus appears that many pieces of modern technology are designed to handicap the older person. The Centre for Applied Gerontology at Bir-mingham University has a notable slogan: ‘design for the young and you exclude the old; design to the old and you include the young’. It is not being argued that every item should be designed to be age-impartial, but it is hard to see why manufacturers seem to want to exclude at least 20 per cent of their potential market by making things difficult. It should also be noted (and this is not intended to be an ageist statement) that in designing with older people in mind, it is also aiding many younger adults with physical problems, such as people with poor vision or limited dexterity.

On the reverse side of this argument, there is a danger that in making such pronouncements one is presenting a view of older people being disadvantaged to a greater extent than they are. For example, several publications and Web sites give advice on designing computer interfaces which as first priority stress the need for adequate wheelchair access, simple instructions and very large print. Of course these are necessary pieces of advice (for a small proportion of older adults), but at times one might wish that these pieces of advice were given a little less prominence Accordingly, technological advances are a mixed blessing to older people. While they promise great hope, many of the details of their operation have not been sufficiently thought through. Machines which are designed to help save labour may be impossible to operate or create more harm than good. Medical advances will cure some illnesses but still leave older adults vulnerable to others. A medical break-through which could delay the ageing process is a mixed blessing because it invites people to extend the time in which they can suffer, as well as enjoy life. To imagine that older people will automatically be made happier by such advances is foolishly optimistic.

Conclusion

A view of the future almost inevitably stems from a criticism of the present, and many of the predictions and arguments raised in this and the previous chapter are fuelled by the current problems with gerontological research and with the lot of older people in industrialised societies. However, it would be unfair to conclude from this that something is rotten in the state of psychogerontology. The area shows a healthy growth and an agreeably wide range of interests. The predictions presented in these final two chapters can be divided into two sorts – those which ought to come true and those which might. In the former camp fall those born of criticisms of existing

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research methods. Researchers must stop treating older people as if they are a race apart. Not only is it unscientific, but it is also patronising and divisive. On a milder note, although some moves have been made in this direction, the ageing mind needs to be seen more as an interactive process and less as a set of single systems. The approach of isolating a single aspect of ageing and analysing it in great detail is analogous to the old chestnut about three blind men examining an elephant –
depending upon which part of the animal they felt, the men identified the animal as being like a snake, a tree or a bird (there are other, often ruder versions of the same tale, in case this one is unfamiliar to the reader). Inevitably, changing to a multifactorial model leads to problems an a single figure result is never likely to suffice. However, as the inestimable Mr Wilde wrote, the truth is never pure and rarely simple. The second set of predictions concerns possible future changes in technology and attitudes, and how these might affect older people. It is improbable that many of the changes described will be readily apparent for several years at least. It is always tempting to think that technology will inevitably shape lives. A possibility rarely considered is that people will simply ignore it. Older people may resist new inventions, not because of inbuilt conservatism (which in any case Chapter 5
demonstrated to be an ageist conceit), but because they cannot see the worth of adopting new practices which are likely to be of only limited use. Perhaps in many ways this is the most optimistic vision one could have of future generations of pensioners – older adults standing up for what they want, rather than what younger adults are foisting on them ‘for their own good’.

If there is a message to be taken from this book it is this: Whether an older person is mentally advantaged or disadvantaged, content with life or suicidal, healthy or housebound, principally or solely depends upon their genetic inheritance and how he or she behaved earlier in life. A content later life is a reward, not an automatic right. It can only be reached by approaching the prospect of ageing with a clear and open mind. Some changes, such as the intellect, can only be partially controlled, but even though there may be some decline, this should never, with the exception of dementia, be sufficient to mar a productive and happy later life. For those unmoved by this argument, and still insist on stereotyping older people as an homogenous, inferior group, there remains a final thought. All older people are survivors: this is an accolade which not all their younger detractors will live long enough to proclaim for themselves. This is the one fact which describes every older person.

Glossary of Technical Terms

The Glossary contains definitions of the technical terms printed in bold type in the main body of the text. In addition, it includes definitions of terms not mentioned in the text, but in common or relatively common use in the gerontological literature.

An italicised word within a definition indicates that it has its own entry in the Glossary. An entry in bold italics indicates that the term is defined within the definition being read, and that the term’s own entry will refer the reader back to the current definition.

A-68 Protein found in abnormally high concentration in patients with dementia of the Alzheimer type.

AAMI Age-associated memory impairment.

acceptance of prospect of dying stage See Kubler-Ross’s stages of dying.

accommodation (vision) The ability to focus at different distances.

acetylcholine Type of neurotransmitter.

acquired dysgraphia A profound difficulty in writing (particularly spelling) resulting from brain damage.

acquired dyslexia A profound difficulty in reading resulting from brain damage.

ACS Acute confusional state
active life expectancy The average number of years remaining in which an individual, or more generally members of an age cohort, can expect to lead an active life.

activity theory The counter-argument to disengagement theory, which argues that older people should be kept involved and active in the community.

acuity (vision) Ability to focus clearly.

acute brain disorder acute confusional state acute brain dysfunction acute confusional state 217

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acute confusional state (ACS) A major disturbance (usually temporary) in intellect and perception resulting from a general deleterious change in the central nervous system’s metabolism (e.g. through fever, intoxication, drug overdose). Can be confused with dementia, but its very rapid onset is in itself a sufficiently distinguishing feature.

acute crisis phase (of dying) See Pattison’s stages of dying.

AD Alzheimer’s Disease.

AD-MID A dementia in which the patient displays symptoms of dementia of the Alzheimer’s type and multi infarct dementia simultaneously.

ADL Assessment of daily living.

aetiology The origin and causes (particularly of disease).

affect Emotion.

afferent (neurons) Carrying signals from the peripheral nervous system to the central nervous system.

age-appropriate behaviour Social age.

age-as-leveller The argument that later life diminishes the perceived differences between socio-economic/ethnic groups.

age associated memory impairment (AAMI) Pronounced memory decline in later life, which is associated with ageing, rather than dementia or similar.

age bias Age discrimination.

age cohort A group of people born and raised in the same period of time/history.

age discrimination Unfair bias against a person because of his/her age.

age-equivalent scale Test scores expressed in terms of the proportion of an age group who typically possess them. Thus, whether a person is advanced or ‘retarded’ for their age can be assessed.

age grading The societal pressures which determine what is considered appropriate for different social ages.

age norm The mean score on a test for a given age group, and hence a gauge of what is typical for that age group.

age normative effect A factor which influences the majority of people at the same point in their lives.

age scale Age equivalent scale.

GLOSSARY / 219
age set Age cohort.

age-specific mortality rate Proportion of people in an age group likely to die before they get too old to be in the said group.

age stratification Dividing the lifespan into a series of social ages.

age x complexity effect The phenomenon that the difference between older and young adults gets disproportionately larger the more complex the task set. See age x treatment interaction.

age x process interaction Age x treatment interaction.

age x treatment interaction The phenomenon that some psychological skills decline more than others in later life (see differential preservation and preserved differentiation).

Thus: if skill 1 requires mental process X and skill 2 process Y, but skill 1 declines disproportionately more than skill 2 in later life, then process X must be more affected by ageing than is process Y. This is not the same as the age x complexity effect, which argues that changing the complexity of items which the same skill has to process has a disproportionate effect on older participants.

AGECAT A computerised package for assessing the mental state of older patients.

ageing Process of change occurring with the passage of time. Usually restricted to changes (often perceived as negative) which occur after adolescence. See anatomical age, biological age, carpal age, chronological age, distal ageing effects, physiological age, primary ageing, probabilistic ageing, proximal ageing effects, secondary ageing, social age and universal ageing.

ageing/aging Either spelling is acceptable. However, citizens of the USA tend to use

‘aging’ and UK inhabitants ‘ageing’.

ageism Age discrimination (usually refers to discrimination against older people).

agerasia Hutchinson-Gilford syndrome.

aging See ageing/aging.

agoraphobia Fear of open spaces.

AIDS dementia Form of dementia found in some patients in the terminal stages of acquired immune deficiency syndrome (AIDS).

alcoholic dementia (1) Old (and misleading) synonym for Korsakoff ’s syndrome. (2) A dementia resulting from long-term alcohol abuse, and similar to Korsakoff ’s syndrome although with a different neuroanatomical pattern of decay (this distinction is controversial and not universally accepted).

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alexia A complete failure to read or to recognise words or letters (in dyslexia there is a partial ability). Only usually seen in brain-damaged individuals.

alpha waves A pattern of electrical activity detected by EEG with a frequency between 8 and 12 Hz.

aluminium theory of dementia of the Alzheimer type Brain cells of Alzheimer patients show unusually large concentrations of aluminium, leading to the theory that the principal cause of dementia of the Alzheimer type is the ‘poisoning’ of the brain with aluminium contamination. However, recent work suggests that this may be an artefact of the manner in which the cells are analysed.

alumni education US term for education schemes for former students (alumni) of an institution of higher education. The courses are typically intended for intellectual enrichment, rather than for specific postgraduate qualifications such as a Masters or PhD degree.

Alzheimer-type dementia Dementia of the Alzheimer type (DAT).

Alzheimer’s disease (AD) Dementia of the Alzheimer type.

ambiguous loss Phenomenon usually encountered in severely demented patients, that the afflicted individual exists only physically - there is no sign of a sentient being occupying the body.

amenity migration Moving from one country or area of the country to another because there are better amenities/lifestyle, etc. The term is often used to describe retired people moving to a ‘nice place in the country’.

amnesia A failure of memory. Usually arises as a result of stroke, head injury, illness (e.g.

dementia), or poisoning (e.g. chronic alcoholism).

anaphoric reference Referring to a previously named person, persons, thing or things by the appropriate noun (e.g. mentioning ‘the man’ and then in the next sentence citing the same character as ‘he’.

anatomical age Biological age, measured through relatively gross state of body (e.g.

bone structure, body build etc) rather than through physiological age. See carpal age.

anger at prospect of dying stage See Kubler-Ross’s stages of dying.

anniversary reaction Negative feelings engendered by it being the anniversary (or general time of year) of an event distressing to a person (e.g. death of a close friend or relative).

GLOSSARY / 221

Anomalous Sentences Repetition Test (ASRT) Test designed to identify patients in early stages of dementia from those with pseudodementia. Participants are required to repeat sentences spoken by the tester.

anomia A failure to name objects.

antediluvian ageing myth Myth that at some distant time (antediluvian = ‘before the flood’), a (usually virtuous and pious) race of people existed, who had incredibly long lifespans. See hyperborean ageing myth.

anticholinergic Anything which blocks the action of the cholinergic system. This can lead to severe memory loss, and this information is one of the cornerstones of the cholinergic hypothesis.

anticipatory grief Preparing for the death of a loved one.

anxiety disorder A long-lasting state of anxiety characterised by symptoms such as extreme restlessness, insomnia, and fatigue, producing distress and impairment of function. It can manifest itself in many forms, including phobias (an irrational or inappropriately high fear of an item or event, such as open spaces, spiders, etc), generalised anxiety (a perpetual feeling of anxiety, often accompanied by physical symptoms such as sweating, being aware of a pounding pulse, etc); obsessive-compulsive disorder (a condition in which to relieve anxiety feelings, the patient is compelled to repeat the same act - e.g. repeatedly washing the hands to remove anxiety-invoking dirt, etc), and panic disorder (characterised by repeated panic attacks - sudden attacks of overwhelming apprehension, shortness of breath, feeling of loss of control, etc).

apathetic (personality) See passive-dependent personality.

aphasia A failure of language. See Broca’s aphasia and Wernicke’s aphasia.

Aphasia Screening Test Sub-test of the Halstead-Reitan Neuropsychological Battery, used to assess for signs of aphasia.

apnoea Temporary suspension of breathing, usually in sleep. Commoner in infants and older people. Several possible causes.

apportioned grandmother See Robertson’s taxonomy of grandmothers.

apraxia An inability to perform skilled movements.

armoured approach personality Defensiveness personality.

armoured-defensive personality Personality type found in Neugarten et al. ’s (1961,1968) studies. Possessors of this type were either holding on (maintaining a

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high level of activity to ‘defeat’ ageing); or constricted (dwelling on what they had lost through ageing).

articulatory loop Previous term for the phonological loop.

ASRT Anomalous Sentences Repetition Test.

assessment of daily living (ADL) Any method of measuring daily activities, usually with the purpose of identifying memory slips, ability to cope independently, etc.

attention The ability to concentrate on a target item(s) despite distracting stimuli. See divided attention, selective attention, and sustained attention.

autobiographical memory Memory for events peculiar to one’s own life, as opposed to past events which everyone has experienced (i.e. events which have been ‘in the news’ such as general elections, train crashes). See flashbulb memory and observer memory.

autoimmune theory of ageing Theory that the ageing body’s autoimmune system falters and begins to attack the body’s own cells as if they were infections. See disposable soma theory of ageing, Hayflick phenomenon, and somatic mutation theory of ageing.

autonomic (neuron) Carrying signals from the central nervous system to bodily systems over which there is little conscious control (e.g. glands, smooth and cardiac muscle).

awareness of dying The degree to which a person is aware s/he has a fatal illness.

baby boom Age cohort of people born between the mid-1940s and 1960s, when there was an appreciable increase in the birth rate in the USA and other westernised nations.

backward masking A method used in iconic memory experiments. A to-be-remembered item is presented for a brief period of time on a display screen, and is immediately supplanted by a different image (a ‘mask’) which has the potential (depending upon its appearance, intensity, etc.) to destroy the memory of the to-be-remembered item. This process of disrupting the memory trace is called backward masking.

backward span A short-term memory task in which a list of items is presented to the participant, who must repeat them back in reverse order of presentation – a more sadistic form of the ordered recall task.

Baltes’s theory of lifespan development A rich and complex theory, devised by psychologist P. Baltes. Argues that development is determined by three factors –
purely environmental, purely biological, and mixtures of biological and environ-

GLOSSARY / 223
mental. These influences express themselves through three strands of development. (1) normative age-graded development is the basic developmental pattern one would expect to find in any normal individual (e.g. in terms of biological ageing, the onset of puberty, in terms of social ageing, the effects of retirement on behaviour and attitudes). (2) normative history-graded development charts the effects of historical events which would normally be experienced by the whole of the age cohort (e.g. experience of food rationing would be normal for most English people born before 1940, but would be unusual for people in their twenties). (3) non-normative
life development measures the effects of major events unique to an individual’s life.

bargaining at prospect of dying stage See Kubler-Ross’s stages of dying.

BDI Beck Depression Inventory.

BDS Blessed Dementia Scale.

Beck Depression Inventory (BDI) A multiple choice questionnaire, where the participant is required to indicate which of a choice of responses best describes him/herself in relation to a range of potentially depressive attributes.

Behaviour Rating Scale (BRS) See Clifton Assessment Procedure for the Elderly.

benign senescent forgetfulness Age associated memory impairment.

beta waves A pattern of electrical activity detected by EEG with a frequency above 12

Hz.

Big Five (personality) Model of personality which identifies five basic personality traits: conscientiousness (how reliable a person is), agreeableness (how compliant with others’ wishes), openness (how willing to cope with the unfamiliar), extraversion, and neuroticism.

Binswanger’s disease Form of vascular dementia.

biographical approach The analysis of the lives of pre-eminent members of profes-sions, etc, to see if there are any common factors to explain their greatness. Has been widely used in creativity research.

biological age The body’s state of physical development/degeneration. This is gauged against the state of an average person of the same chronological age. See anatomical age, physiological age.

bipolar disorder Mental illness characterised by alternate episodes of extreme and unrealistic elation and hyperactivity (mania) and depression. Better known by its older name of manic depression.

birth cohort A group of people born in the same period of time. See cohort.

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Blessed Dementia Scale (BDS) A measure of intellectual impairment and functioning, usually employed in the assessment of demented patients. The test requires the patient to answer some simple memory questions (e.g. ‘what is your name?’, ‘who is the current prime minister?’) and to perform some simple intellectual tasks (e.g.

‘count backwards in steps of three’). Details of how capable the patient is of looking after him- or herself are collected from a caregiver. The test provides a useful

‘ready reckoner’ of how intellectually impaired a patient is, and how much professional nursing care and assistance is required. The Blessed Dementia Scale (named after its author, Dr Blessed) is a British test. The American equivalent is the Mental Status Questionnaire, which has a similar format.

blood-brain barrier A physiological mechanism which prevents potentially damaging chemicals in the bloodstream from entering the brain.

body transcendence versus body preoccupation In Peck’s theory, realising that in later life, bodily fitness and health can no longer be a prime cause of self esteem.

bovine spongiform encephalopathy (BSE) Degenerative disease of the nervous system in cattle, colloquially known as mad cow disease. The cause is unknown – the most popular theory is that it is due to cattle eating infected feed.

bradykinesia Very slow movement; a common feature of Parkinsonism.

bradylexia Very slow (but not necessarily inaccurate) reading.

brainstem Section of the brain which is the meeting place between the spinal cord and the brain. Besides acting as a relay station between the spinal cord and other areas of the brain, the brain stem controls many life support mechanisms (e.g. blood pressure, respiration).

brick test Semi-serious term for a creativity test in which the participant must think of novel uses for an everyday object (often a house brick, hence the name).

Brinley plot Plot of older adults’ response times versus younger adults’ response times on the same set of tasks. For both age groups, times get slower the more complex the task, but the plot of the older versus the younger times is linear (i.e. it appears as a straight line on a graph). This supports the general slowing hypothesis.

Broca’s aphasia A specific problem with producing speech, resulting from brain damage.

Brown-Peterson task Named after its inventors, the task presents participants with a list of to-be-remembered items, then gives them a distracting task (usually counting backwards in units of 2 or 3), before asking participants to recall the to-be-remembered items.

GLOSSARY / 225

BRS Behaviour Rating Scale.

BSE Bovine spongiform encephalopathy.

bulimia The uncontrollable urge to over-eat.

CAD Cortical atherosclerotic dementia.

CAMDEX Cambridge Mental Disorders of the Elderly Examination – a test battery of measures for assessing older people for dementia and other aspects of mental health and psychological wellbeing.

CAPE Clifton Assessment Procedure for the Elderly.

caregiver A person who looks after a patient or child. In the context of this book, the term usually refers to the relative of an older patient who is principally responsible for the latter’s welfare.

Caregiver Strain Index (CSI) Measure of stress and strain in caregivers (usually caregivers of older patients).

caretaker (1) Caregiver (2) For the benefit of American readers – ‘caretaker’ is commonly used in British English to denote a janitor, particularly of a school.

carpal age Chronological age calculated through the state of the wrist (carpal) bones.

CAS Cognitive Assessment Scale.

cascade model of ageing Model of ageing which argues that changes begin in a relatively slight fashion, and then gather momentum and accelerate in severity.

cataracts A progressive opaqueness of the lens, ultimately causing blindness.

catastrophe theory Error catastrophe theory.

CBS Chronic brain syndrome.

CDR Clinical Dementia Rating.

CDT Clock drawing test.

cellular garbage theory Model of ageing which argues that the decline of the older body is attributable to the accumulation of ‘waste products’ from the cells’ metabolic processes.

central executive The section of the working memory model which controls and oversees the specialist slave systems. The central executive is itself a memory store (though of limited capacity).

central nervous system (CNS) The collective term for neurons forming the brain and the spinal cord.

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cerebellum Area of the brain primarily responsible for balance and co-ordinating movement.

cerebral cortex Usually known by its abbreviated name of cortex. The cerebral cortex is the characteristic wrinkled surface of the brain. It is divided into two linked hemispheres and can be divided into four regions or lobes which display different functions. The cerebral cortex is responsible for the majority of higher intellectual functioning.

cerebral haemorrhage Bleeding in the brain. See subdural haematoma.

cerebrospinal fluid Fluid which cushions and in part supplies the brain with nutrients.

CFQ Cognitive Failures Questionnaire.

changing environment effect Cohort effect.

childhood amnesia Phenomenon that autobiographical memories of early childhood are scarce or non-existent.

choice reaction time (CRT) The time taken for a participant to make the correct response when there is more than one stimulus, and each stimulus requires a different response. Compare with simple reaction time.

cholinergic hypothesis Theory that much of the memory loss in dementia of the Alzheimer type can be attributed to depletion of the cholinergic system. See ganglioside, ondansetron, and tacrine.

cholinergic system Shorthand for the network of neurons which use the chemical acetylcholine as their neurotransmitter. About 90 per cent of neurons in the brain are cholinergic.

chronic brain syndrome (CBS) Long-term degeneration of brain tissue, resulting in severe impairment of personality and/or intellectual functioning.

chronic living-dying phase (of dying) See Pattison’s stages of dying.

chronological age The length of time a person has been alive.

chunking A mnemonic strategy for making long lists of items easier to remember. Items are grouped (‘chunked’) into sub-groups of 3 or 4 instead of being treated as a continuous list. Thus, the sequence 1789675401 might be ‘chunked’ into 178 967

5401.

CI Cognitive impairment.

circumlocution Talking around the topic in question because the appropriate word cannot be recalled (found to spectacular effect in some demented patients).

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CJD Creutzfeldt-Jakob Disease.

classic ageing curve (Erroneous) belief of some early researchers that intelligence peaked in early adulthood and then gently declined across the rest of the lifespan.

classic ageing decline Pattern of relative preservation of crystallised intelligence-based skills and decline of fluid intelligence-based skills in older people.

Clifton Assessment Procedure for the Elderly (CAPE) Test battery consisting of two

‘sub-batteries’ – the Cognitive Assessment Scale (CAS) and the Behaviour Rating

Scale (BRS), measuring intellectual skills and personality respectively, in older participants (particularly hospital patients and institutionalised older people).

Clinical Dementia Rating (CDR) A ‘checklist’ for assessing the level of functioning a patient suspected of dementia is capable of on various tasks. From this his/her level of impairment, and hence the severity of the dementia can be calculated .

clock drawing test (CDT) Measure of visuo-spatial skills in which the participant is required to copy an analogue clock face.

CNS Central nervous system.

cognition The study of thought processes (including memory and problem solving).

cognitive Pertaining to cognition.

Cognitive Assessment Scale (CAS) See Clifton Assessment Procedure for the Elderly.

Cognitive Failures Questionnaire (CFQ) A test which asks participants to report instances of memory failure in recent everyday life (e.g. forgetting to buy items when shopping).

cognitive impairment (CI) An appreciable impairment of cognitive abilities sufficient to interfere with the norms of independent living. Often used as a general term for the declining intellectual skills in patients suffering from dementia, acute confusional state and other illnesses with similar effects.

cohort A group of people with a shared characteristic. Usually describes a group of people raised in the same environment and/or period of time, and thus is often used as a synonym for age cohort.

cohort effect A difference between age groups which is better attributed to differences in the ways they were raised and educated rather than to their ages per se.

cohort sequential design Overlapping longitudinal study.

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compensation General and often ill-defined theory that older people can compensate for failings in one (usually fluid intelligence-based) skill by increasing their reliance on another (usually crystallised intelligence-based). See molar equivalence (ME).

complexity effect Age x complexity effect.

component efficiency hypothesis Hypothesis that the decline in a skill is due to a decline in one or more of the ‘basic’ sub-skills governing it.

computed tomography A method of electronically scanning the body (in the context of this book, the brain) and taking the equivalent of X-rays of narrow slices of tissue.

conceptual organisation The ability to treat items at an abstract level in order to uncover basic rules and principles and group items accordingly.

concurrent processing Holding items in working memory while performing a potentially distracting task at the same time (a common everyday experience is remembering a telephone number while dialling). By changing the nature and/or level of difficulty of the distracting task, the degree of memory loss can be affected. A technique frequently used to test how well participants can retain information in memory. In the working memory model, concurrent processing is held to be controlled by the central executive.

confabulating Condition in which the patient makes up stories or other implausible explanations to cover up gaps in his/her memory or other skills. Generally, the term is reserved for situations in which there is no conscious attempt to deceive.

confounding variable A variable which may distort the finding of primary interest. In psychology of ageing, this nearly always means the cohort effect.

constraint seeking strategy In solving a problem (e.g. in a ‘twenty questions’ game), seeking answers which progressively reduce the set size of all possible answers.

constricted (personality) See armoured-defensive personality.

constructiveness Personality type discovered by Reichard et al. (1962). Older people possessing it had come to terms with their lives, and were prepared to help others.

contextual perspective The belief that ageing effects are in a large part attributable to social and environmental effects rather to a biological process.

contrast sensitivity function (CSF) A measure of the changing ability to focus clearly on a fine pattern of dark and light parallel lines when the relative darkness and lightness, and thickness of the lines is altered.

corpus callosum The principal link between the left and right hemispheres of the brain.

GLOSSARY / 229
correlation A statistical term which, technically speaking, means how much of the variance in one variable can be predicted by variance in another. In layperson’s terms, a correlation describes the strength of the relationship between two variables, and the extent to which a change in one is met by a change in the other. Correlations are represented by the symbol r. Correlations can be positive (i.e. as one variable increases, so does the other) or negative (i.e. as one variable increases, the other decreases). Correlations also vary in strength – a value of 0 means that no relationship exists between the variables, a value of 1 indicates perfect positive correlation (i.e.

for every increase in one variable, there is exactly the same increase in the other) and a value of -1 indicates perfect negative correlation (i.e., every rise in one variable is met with exactly the same fall in the other). In ‘real life’, correlations fall somewhere between these extremes. The closer the figure is to 1 or -1, the stronger the correlation (typically, a value of 0.3 or better is taken to be a good indicator).

‘Correlation’ is not synonymous with ‘causation’. There is no method of deciding whether one variable is causing the other to alter. It should also be considered if both might not be governed by a third party (see partial correlation). A correlation can only show that two variables are associated with each other. For the mathematically minded: the percentage of the variance in one variable which the other predicts can be easily calculated by squaring r and multiplying the result by 100 (e.g.

variables A and B correlate at 0.6; A predicts 36 per cent of B’s variance).

Corsi blocks task A test of visuo-spatial memory. Participants are shown an array of blocks positioned on a table. The experimenter taps on some of these blocks in a sequence which the participant is asked to copy. The experimenter gradually increases the length of sequence until the subject’s memory span is discovered.

cortex See cerebral cortex.

cortical Pertaining to the cerebral cortex.

cortical atherosclerotic dementia (CAD) Vascular dementia whose primary damage occurs in the cortex.

cortical dementias Dementias whose principal focus of damage is in the cerebral cortex.

creativity The ability to produce novel and appropriate ideas and solutions.

Creutzfeldt-Jakob Disease (CJD) A very rare dementia, contracted through contact with diseased nervous tissue. In addition to archetypal demented symptoms, there are severe disturbances of gait and movement. A new variant ( nvCJD) has appeared in recent years, and has been plausibly (though not conclusively) linked to consuming beef or other products infected with bovine spongiform encephalopathy.

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critical loss Pertaining to the terminal drop model, the theory that a decline in some intellectual abilities can be endured, but that a fall in others constitutes a ‘critical loss’

which heralds death.

cross-linking theory of ageing Theory that the physical decline of the older body can be attributed to a loss of elasticity of tissues (skin, muscle etc).

cross-sectional research/samples/study An experimental method where age differences are measured by testing different age groups in the same test period. Contrast with longitudinal research/samples/study, and see overlapping longitudinal study.

CRT Choice reaction time.

crystallised intelligence The amount of factual (as opposed to autobiographical) knowledge a person has acquired during a lifetime – roughly corresponds to the lay term ‘general knowledge’.

CSI Caregiver Strain Index.

CT/CT scan See computed tomography.

cued recall Experimental technique for assessing memory in which the participant is given information about the item s/he is supposed to recall (i.e. s/he is given a

‘hint’, such as the first letter of a to-be-remembered word).

CV Cardiovascular (i.e. pertaining to the heart and blood vessels).

cytologic theory Theory of ageing that bodily decline can be attributed to ‘poisoning’

by toxins (including the waste products of metabolic processes). Compare with wear and tear theory.

DAT Dementia of the Alzheimer Type.

death preparation Preparing for the psychological and practical impact of the death of oneself or of a loved one. Usually helps to lessen the negative effects of the event.

To some extent, ‘passive’ death preparation increases with age, as the probability of dying increases.

defensiveness personality Personality type discovered by Reichard et al. (1962). Older people possessing it had a strong urge to carry on working to ‘prove’ they were still young.

delirium See acute confusional state.

Delirium Rating Scale (DRS) A test assessing the likelihood that a patient’s symptoms indicate delirium (acute confusional state) rather than an illness with which it can be easily confused (e.g. dementia).

GLOSSARY / 231
delta waves A pattern of electrical activity detected by EEG with a frequency between 0
and 4Hz.

demented Describing the state associated with dementia.

demented dyslexia A condition found in some demented patients, where they can read aloud perfectly normally, and yet have no understanding of what they are reading.

dementia A global deterioration of intellectual function, resulting from atrophy of the central nervous system. The illness takes many forms: the commonest are dementia of the Alzheimer type and multi-infarct dementia. In some (older) textbooks, ‘dementia’

refers purely to those cases arising in pre- senile patients, and senile dementia to cases in senile patients. This distinction is now largely disregarded.

dementia of the Alzheimer type (DAT) Form of dementia whose symptoms have a characteristic pattern, first described by Alois Alzheimer in the 1900s.

dementia praecox Now outmoded term (invented by Emil Kraeplin 1883) for the illness now known as schizophrenia. The term means ‘pre-senile dementia’, but should not be confused with the condition now graced with that name.

dementia pugilistica Pugilistic dementia.

dementia syndrome of depression (DSD) Pseudodementia.

denial of dying stage See Kubler-Ross’s stages of dying.

dental age Calculation of chronological age from the state of the subject’s teeth. Useful for dead humans and live horses.

dependency ratio The ratio of working to non-working members of the population.

dependent personality Personality type discovered by Reichard et al. (1962). Older people possessing it had some life satisfaction, but relied on others to help them.

depression at prospect of dying stage See Kubler-Ross’s stages of dying.

depression-related cognitive dysfunction Pseudodementia.

depression with cognitive impairment Pseudodementia.

depressive pseudodementia Pseudodementia.

deterioration quotient (DQ) Measure of rate of intellectual decline associated with ageing. Sections of the WAIS (or indeed many other intelligence test batteries) can be divided into those measuring crystallised intelligence (held to be unaffected by ageing), and those measuring fluid intelligence (held to decline with ageing). These can also be referred to as hold tests and don’t hold tests respectively. The DQ is calculated as {[(score on hold tests)–(score on don’t hold tests)]/(score on hold tests)} x

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100. A phenomenon of the WAIS is that hold and don’t hold scores are equal in early adulthood. Hence the bigger the gap in an older person’s hold and don’t hold test scores, the greater the deterioration. The DQ expresses this change as a percentage. See efficiency quotient.

Dewey’s paradox of ageing John Dewey, philosopher, argued that ‘we are .... in the unpleasant and illogical condition of extolling maturity and depreciating age’

(Dewey, 1939).

diabetic retinopathy Disorder of vision resulting from diabetes-created damage to the retina’s blood vessels.

Diagnostic and Statistical Manual of Mental Disorders Usually known by its abbreviation of DSM, followed by the suffix of the edition in question. At the time of writing, the current edition is the 4th ( DSM IV). The DSM is the American Psychiatric Association’s (1994) classification of all mental illnesses and handicaps. It is a hugely influential publication, not only in the USA, but also worldwide. The DSM
lists the major symptoms which characterise and distinguish between different mental illnesses and handicaps. It also takes note of life events and physical illnesses which may exacerbate or ameliorate the condition a patient is suffering from.

dichotic listening task A measure of divided attention. Participants hear (via stereo headphones) different messages in either ear, and must then report what they have heard in either ear.

diencephalon Also called the interbrain. A collective term for a number of key segments of the brain ‘sandwiched’ between the brain stem, cerebellum and cortex. More important areas include the thalamus, hypothalamus and hippocampus.

differential preservation The theory that some intellectual skills may be preserved better than others in ageing. See preserved differentiation and age x treatment interaction.

digit span Memory span for numbers.

digit-symbol test A member of the Wechsler Adult Intelligence Test battery, which assesses the ability to learn an arbitrary matching of abstract symbols and numbers.

Diogenese syndrome A condition of extreme self-neglect found in some patients with dementia, characterised by a very pronounced lack of personal hygiene, lack of awareness of filthy and untidy state of their surroundings, etc.

disease cohort A group of people suffering from the same disease. See cohort, patient cohort.

disengaged (personality) See integrated personality.

GLOSSARY / 233
disengagement theory The theory that older people seek to lose much of their contact with the outside world, in preparation for death. See activity theory.

disorganised personalities Personality type found in Neugarten et al.’s (1961, 1968) studies. Possessors of this type were not capable of normal functional behaviour.

disposable soma theory of ageing The theory that the body ‘sacrifices’ replacing all somatic (non-reproduction) cells lost through natural ‘wear and tear’ to concentrate on reproductive fitness. This, it is argued, is the evolutionary force which

‘causes’ ageing. See autoimmune theory of ageing, free radical theory of ageing, Hayflick phenomenon, and somatic mutation theory of ageing.

distal ageing effects Ageing changes attributable to relatively distant events (e.g. poor self-image in later life because of childhood bullying) or events which are only felt through several intermediaries. See proximal ageing effects.

distracters Items which are included along with targets and which the participant may erroneously choose.

disuse theories of ageing Theories which argue that intellectual skills worsen in later life because they are not practised frequently enough.

divergent thinking Usually associated with creativity. The ability to create ideas and solutions stemming from a simple proposition or problem.

divided attention The ability to attend to and process information from more than one source simultaneously.

don’t hold tests See deterioration quotient (DQ).

dopamine Type of neurotransmitter.

double ABCX model An attempt to account for the stress induced in a family by a major crisis befalling one of its older members. The letters refer to variables expressing the seriousness of the crisis, the amount of available help etc.

double jeopardy Term denoting the problem faced by older members of an ethnic minority who face not only ageism but racism as well.

drop-out effect Phenomenon that in a longitudinal study, participants who perceive themselves as performing badly tend to withdraw from further participation, leaving a rump of ‘better preserved’ volunteers, thereby artificially minimising the measurements of ageing change.

DRS Delirium Rating Scale.

DSD Dementia syndrome of depression.

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DSM IV Diagnostic and Statistical Manual of Mental Disorders, 4th edition.

Duke Longitudinal Study 20 years longitudinal study of community residents aged 50+ years in Raleigh-Durnham, North Carolina, USA.

dying trajectory (1) The speed with which a person is likely to die. (2) The emotional and intellectual states associated with dying.

dysarthria Disorder of muscular control of speech (and often of skills associated with the same muscles, such as eating and drinking).

dyscalculia A profound problem with arithmetic skills. Can be developmental or acquired as the result of brain damage in adulthood.

dyslexia A profound reading problem (though note there is evidence of some reading ability). The syndrome can be inherited (developmental dyslexia) or can be acquired through brain damage (acquired dyslexia).

dyslogia Poor spoken articulation.

dysphasia A profound spelling problem.

dysphonia Disorder of voice production.

E Extraversion-introversion.

early onset schizophrenia (EOS) Schizophrenia which first manifests itself before middle age.

echolalia Abnormal repetition of what has just been said.

ecogenic An event not tied to a particular historical epoch. See epogenic.

ecological validity The degree to which a study’s findings bear any relevance to everyday life.

educational gerontology Broadly speaking, the study of education in later life.

Chiefly concerned with the benefits and practicalities of education for older people and the real or illusory barriers to learning they may experience.

EEG See electroencephalograph.

efferent (neurons) Carrying signals from the central nervous system to the peripheral nervous system.

efficiency quotient (EQ) Measure of an older person’s intellectual abilities relative to those of younger adults (who are assumed to be at their peak). Basically, it is the IQ
which the younger adult would be recorded as possessing if s/he had the same raw score as the older person, e.g. an older man has a raw test score of 95, which is good for his age group, and gives him an IQ of 130. However, a score of 95 would be

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poor for a younger adult, and would give him/her an IQ of e.g. 70. The older person’s EQ is therefore classed as 70. By comparing EQ with IQ, a measure of age-related decline can thus be calculated. However, a more useful single measure is probably the deterioration quotient.

ego In Freudian theory, a person’s rational self. See also id and superego.

ego differentiation versus work-role preoccupation In Peck’s theory, coming to terms with retirement, and realising that status is no longer conferred by one’s employment.

ego integration See integrity versus despair.

ego transcendence versus ego preoccupation In Peck’s theory, coming to terms with the fact that one is inevitably going to die.

elder abuse Abuse of older people, particularly those who are mentally enfeebled. The abuse can be physical, but also psychological and/or financial (e.g. extorting money).

eldering Ageing in terms of social age.

elderspeak The use of patronising ‘baby talk’ when talking to older adults.

electroencephalograph Often (understandably) shortened to EEG, this is a device which measures the pattern of electrical activity on the scalp and by extrapolation, of the cerebral cortex underneath. The rate of activity and where on the scalp it occurs can give some insight into how active and healthy an individual’s brain is.

embolism Caused by a blood clot becoming detached and being sent around the blood vessels until it becomes ‘stuck’, causing a blockage.

encoding The process of creating a memory trace.

encopresis Faecal incontinence. See enuresis.

enuresis Urinary incontinence. See encopresis.

EOS Early onset schizophrenia.

episodic memory Memory for personal experiences.

epogenic An event unique to a particular historical epoch. See ecogenic.

EPQ Eysenck Personality Questionnaire.

EQ Efficiency quotient.

error catastrophe theory Model of ageing which attributes bodily decline in later life to faulty replication of proteins.

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ethnogerontology Study of ageing in different ethnic/cultural groups.

etiology See aetiology.

event-based task In prospective memory experiments, a task which requires a response which is prompted by an event or other ‘sign’.

excitatory (neurons) An excitatory neuron either: (a) causes (almost invariably in combination with other excitatory neurons) another neuron to become active, and/or (b) makes a neuron already active send signals at a faster rate.

explicit memory Memory which is consciously retrieved/searched for. Contrast with
implicit memory, which is the recall of items or the use of memorised information which the person is unaware of recalling or even possessing.

extraversion See extraversion-introversion extraversion-introversion A personality trait from Eysenck’s personality model, measuring the degree to which a person is outgoing and self-confident ( extraversion) or shy and retiring ( introversion).

Eysenck’s Personality Questionnaire (EPQ) A test assessing the degree to which a person possesses the personality traits of Eysenck’s personality model.

Eysenck’s personality model A model of personality which argues that personality is composed of a mix of three personality traits – extraversion-introversion, neuroticism and psychoticism.

Famous Names Test (FNT) A measure of remote memory. Participants are presented with a list of names of people famous for brief periods of time since the 1920s and are asked to identify those names which they can remember. Included in the list are some fictitious names, designed to prevent simply replying ‘yes’ to every item.

FAST model Model by Reisberg et al. (1989) which describes 7 stages of progressively worsening intellectual deterioration found in patients suffering from dementia of the Alzheimer type.

feeling of knowing (FOK) A person’s understanding of his or her own level of knowledge (i.e. how good he or she feels his or her knowledge is).

flashbulb memory An autobiographical memory of a key event in one’s life which is perceived as being unusually vivid (like a photograph taken with a flashbulb). There is a debate over whether such events are qualitatively different from others, or whether they simply subjectively appear to be more vivid.

fluid intelligence The ability to solve problems for which there are no solutions derivable from formal training or cultural practices. There is usually an added assump-

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tion that to have a high level of fluid intelligence, a person must be able to solve the problems quickly.

FNT Famous Names Test.

focused (personality) See integrated personality.

FOK Feeling of Knowing.

formal operations In Piaget’s theory of cognitive development, the period from 11
years + when the child begins to think in genuinely abstract terms.

fourth age Period of later life (usually during terminal illness, dementia, etc) when a person is dependent on others for basic welfare provision. See third age.

free radical theory of ageing Free radicals are ions (charged atomic particles) produced in chemical reactions in the body. The theory argues that free radicals damage cells and their chromosomes, thereby causing physical decline. Some theorists argue that consuming extra daily quantities of vitamin C will offset these effects.

See autoimmune theory of ageing, disposable soma theory of ageing, Hayflick phenomenon, and somatic mutation theory of ageing.

free recall A memory task in which items can be recalled in any order (i.e. the order in which they were originally presented does not have to be reproduced). Compare with ordered recall.

frontal lobe dementia Dementia whose origin and primary focus is the frontal lobes.

Akin in many respects to Pick’s disease.

frontal lobes The front section of the cerebral cortex extending back to the temples. Primarily involved in planning and controlling actions and thoughts (e.g. by getting words in the correct order whilst speaking, producing socially appropriate behaviour).

functional age The average age at which a particular set of abilities are found (i.e. it measures how well an individual performs relative to his/her age group).

g General intellectual capacity; the general intellectual ability felt by many researchers to underpin all intellectual skills to a greater or lesser extent (though researchers differ considerably over the extent to which g exerts an influence and the degree to which it is genetically determined).

ganglioside Drug whose effects included the enhanced release of acetylcholine (see cholinergic hypothesis). Has been cited as a possible treatment for patients suffering from dementia. See ondansetron and tacrine.

Gc/gc Symbol for crystallised intelligence.

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GDS Geriatric Depression Scale.

general slowing hypothesis Theory that age changes in intellectual tasks are attributable to a general slowing of neural transmission speeds. Generally used more specifically to denote the argument that performance on all tasks, regardless of complexity, is affected by a constant (as opposed to a disproportionately increasing deficit the more complex the task), as witnessed by Brinley plots.

generalised anxiety See anxiety disorder.

generationally biased stimuli Stimuli (or other test materials) which will only be recognised by, or be most familiar to, a particular age cohort.

Geriatric Depression Scale (GDS) A ‘yes–no’ questionnaire measuring the level of depression in the respondent. The questions are geared to match the symptoms and lifestyles typically found in depressed older people.

Geriatric Mental State (GMS) A standardised interview package for assessing the mental status of older patients.

geriatrics Medical treatment and study of older people. See gerontology.

geronting Ageing in terms of psychological ageing.

gerontologists Practitioners of gerontology.

gerontology The study of ageing and later life. The term is often restricted to psychological, sociological and more generally the social scientific aspects of ageing.

gerontopsychology Psychogerontology.

geropsychology Psychogerontology.

Gf/gf Symbol for fluid intelligence.

Gibson Spiral Maze A test of psychomotor skill, in which the participant is required to trace a pencil line around a spiral shaped path as quickly and accurately as possible.

glaucoma An excess accumulation of fluid in the eyeball, increasing pressure on retinal cells, leading to their (permanent) destruction.

GMS Geriatric Mental State.

Gorham Proverb Interpretation Test Measure of intelligence through ability to interpret proverbs. See proverb interpretation.

graceful degradation The phenomenon that the considerable cell loss which typically accompanies ageing is reflected in a gentle loss of memories and level of skill (rather than a wholesale and absolute loss).

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granny dumping Slang term for the process whereby caregivers (usually adult children) who cannot cope with an older relative abandon him/her to the local authorities (sometimes literally leaving him/her on the doorstep of the local hospital/social services office).

granulovacuolar degenerations Malformed dead neurons which under a microscope look like dense granules.

greying population A population in which there is an appreciable increase in the proportion of older adults within it.

Hachinski Ischaemic Score (IS) A diagnostic technique identifying vascular dementias.

Patients are scored on the number of symptoms they display, with strongly indicative symptoms being weighted.

haemorrhage Rupture of a blood vessel wall.

Halsted-Reitan Neuropsychological Battery (HRNB) A battery of neuropsychological tests, assessing abstract reasoning, linguistic, sensory, visuo-spatial, and motor skills.

Hayflick limit See Hayflick phenomenon.

Hayflick phenomenon Named after its discover, L. Hayflick. Living cells taken from a body can be reared in a laboratory, and will reduplicate a limited number of times (the Hayflick limit). The older the animal from which the cells are taken, the lower this number is. This implies that the upper limit of life expectancy may be due to the simple fact that the body’s cells only reduplicate a limited number of times (which in turn may be affected inter alia by the length of the telomeres).

hearing impairment (HI) Loss of auditory sensitivity sufficient to cause handicap. Often measured in terms of the minimum volume (measured in decibels, or dB) which can be reliably heard (the higher the figure the worse the impairment). For example, a hearing loss of > 90dB means that the quietest sound which a person can hear is over 90 decibels (i.e. about the same noise level as heavy traffic). See profound hearing impairment and severe hearing impairment.

hemispheres (cortex) The cerebral cortex is divided into two equally sized halves, or hemispheres, along a vertical axis running from the front to the back of the head. In most individuals, the left hemisphere tends to specialise in linguistic and the right in visuo-spatial skills. The hemispheres are linked by several pathways, of which the most important is the corpus callosum.

HI Hearing impairment.

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hierarchical approach (intelligence) The theory that intelligence comprises a general intellectual ability ( g) and a range of more specialised skills.

hippocampus Area of the brain particularly concerned with memory and the transfer of information from short- to long-term memory. Damage to this area can result in a particularly debilitating amnesia, characterised by failure to retain any new information.

Hutchinson-Gilford syndrome Extremely rare disease with onset in infancy characterised by accelerated physical (though not mental) ageing. Patients have a characteristic ‘bird-like’ appearance of large hooked nose and bulging eyes. Death is typically in the early teens.

hyperactivity An inappropriately high level of activity, which either cannot be controlled, or can be, but only with difficulty. Characteristic of some patients with dementia, who may pace up and down or begin wandering.

hyperborean ageing myth Myth that there is a distant land where people have incredibly long lifespans. See antediluvian ageing myth.

hyperlexia Reading accurately but with no or little comprehension of what is being read. See demented dyslexia.

hypermetamorphosis The compulsive urge to touch everything.

hyperorality The urge to put everything seen into the mouth.

hypokinesia Difficulty in imitating a movement.

hypothalamus Subcortical section of the brain, whose primary task is to assist in the control of bodily drives (e.g. hunger and satiety, anger, sex).

hypothesis scanning Asking specific questions to seek verification of a specific hypothesis.

iatrogenic illness Describes any complaint induced by medical treatment (e.g. drug side-effects).

iconic memory Memory for items which appear for a fraction of a second and disappear before there is time for them to be fully processed and recognised.

id The basic appetitive urge that Freud argued underpinned human behaviour. See ego and superego.

illusions Distorted perceptions.

immune system theory of ageing autoimmune theory of ageing.

implicit memory See explicit memory.

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individualised grandmother See Robertson’s taxonomy of grandmothers.

infarct (a) The cell death caused by damage to the blood vessels supplying the cells in question. (b) The whole process of blood vessel damage and resulting cell death (though strictly speaking, this is infarction).

infarction The creation of an infarct.

inhibition deficit Generally, a failure to inhibit: can refer to an age-related problem of failing adequately to inhibit unnecessary pieces of information or actions. For example, in trying to remember a list of words, failing to ‘block out’ items from a now-redundant list learnt earlier.

inhibition theory A theory of cognitive ageing which argues that older people become less proficient at inhibiting extraneous information and concentrating on the task at hand.

inhibitory (neurons) An inhibitory neuron (almost invariably in combination with many other inhibitory neurons) either slows or prevents the activation of another neuron.

initial letter priming Providing participants with the initial letters of words which the participants are trying to recall.

institutionalised behaviour Nebulous term for deleterious changes in some individuals, resulting from a (usually lengthy) spell in an institution (e.g. hospital, retirement home). Such afflicted individuals tend to have poor social skills, lack of

‘individuality’, lowered intelligence test scores, and so forth.

integrated personality Personality type found in Neugarten et al.’s (1961, 1968) studies. Possessors of this type were of three kinds: reorganisers (finding new things to do as old ones became impractical); focused (activities were restricted in scope, but were rewarding); or disengaged (deliberately avoiding responsibilities).

integrity versus despair In Erikson’s theory, a conflict which has to be resolved in later life – whether to come to terms with one’s past ( ego integration) or to feel that past events cannot be amended.

intellectual realism Term (first used by Luquet, 1927) describing drawings or pictures in which the ‘true’ state of the object is represented rather than what can be seen (‘perceptual realism’).

intelligence quotient (IQ) Often (erroneously) used as an exact synonym of ‘intelligence’. IQ denotes a person’s intellectual skills relative to his/her age cohort (traditionally, a score of 100 denotes average, and scores less than 70 or greater than 130 fairly exceptional). Thus, the same number of questions answered correctly

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(the raw score) means different things to different age groups. For example, an older person with a raw score of, e.g. 40 is probably more gifted than a younger adult with a raw score of 40 on the same test. Hence, the older adult’s IQ is higher than the younger adult’s. IQ tends to stay reasonably constant throughout life (i.e. a person remains in the same position relative to his/her age peers) – it is the raw score which declines in later adulthood.

interbrain See diencephalon.

introversion See extraversion-introversion.

intrusions When referring to linguistic errors, an inappropriate segment of language (e.g. a repetition of an earlier phrase in an inappropriate place in the current statement).

IQ Intelligence quotient.

irregular spelling A word whose pronunciation disobeys the normal rules of spelling-to-sound correspondence. Irregular words abound in English (e.g. ‘quay’,

‘misled’).

IS Hachinski Ischaemic Score.

KDCT Kendrick Digit Copying Test.

Kendrick Battery for the Detection of Dementia in the Elderly Early version of the Kendrick Cognitive Tests for the Elderly.

Kendrick Cognitive Tests for the Elderly Test battery for identifying dementia in participants aged 55 years and over. Consists of two tests. The Kendrick Object

Learning Test (KOLT) is a memory test for arrays of pictures, and the Kendrick

Digit Copying Test (KDCT) measures the speed at which the participant copies a set of numbers.

Kendrick Digit Copying Test (KDCT) See Kendrick Cognitive Tests for the Elderly.

Kendrick Object Learning Test (KOLT) See Kendrick Cognitive Tests for the Elderly.

Kluver-Bucy syndrome A collection of abnormal behaviours, including hyperorality, bulimia, visual agnosia, hypermetamorphosis, and loss of affect.

Korsakoff ’s syndrome (KS) Severe amnesia (particularly for new information) resulting from brain damage caused by long term alcohol abuse coupled with vitamin deficiency through poor diet. Damage is particularly centred in the hippocampus.

Kubler-Ross’s stages of dying Psychological stages exhibited by dying people, according to the work of E. Kubler-Ross (e.g. 1970). Consist of denial of the possi-

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bility of death, followed by anger. Bargaining follows (pleas to the deity, fate, etc), followed by depression, and finally, acceptance. See Pattison’s stages of dying.

KOLT Kendrick Object Learning Test.

lacunar deficits The phenomenon sometimes encountered in brain-damaged patients, where some intellectual functions are almost completely destroyed, whilst others remain relatively intact.

lacunar strokes Form of subcortical arteriosclerotic dementia.

late adult transition The period surrounding retirement.

late life psychosis Any psychosis (any mental illness characterised by a severe loss of contact with reality in the absence of dementia or acute confusional state; principally the term describes schizophrenia) which manifests itself in later life. The condition can appear in tandem with dementing symptoms, but need not do.

late onset schizophrenia (LOS) Schizophrenia which first manifests itself in middle age or later.

late paraphrenia Mental disorder of later life, characterised by symptoms of feelings of persecution and elaborate fantasies of the same. Commoner in women. Can have a variety of causes, including cardiovascular problems and previous episodes of mental illness.

letter strings Groups of letters which may or may not form real words.

Lewy body A form of brain cell damage found in some patients with dementia; the damage comprises a dense round body surrounded by looser filaments.

Lewy body disease A proposed (though not yet universally accepted) category of dementia attributable to the presence of Lewy bodies.

lexical decision task Participants are shown letter strings and must decide as quickly as possible if they form words.

life crisis A set of profoundly negative feelings created by the transition from one social age to another.

life expectancy How much longer a person can expect to live. Typically describes the average remaining life for a particular age cohort, and is often formally defined as the age at which half the cohort will be predicted to have died. Contrast with lifespan.

lifespan The maximum age which a member of a species can expect to live. Contrast with life expectancy.

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living will Signed and witnessed declaration that in the event of becoming so ill as to be placed on a ‘life support’ system, that such apparatus be switched off if there is no prospect of a satisfactory recovery.

long-term memory (LTM) Memory for events of more than a few minutes ago. Long term memory is often sub-classified according to the nature of what is being remembered; see autobiographical, episodic, prospective, remote, and semantic memory.

longitudinal research/samples/study Experimental method in which the same participants are tested at different ages. Compare with cross-sectional research/samples/study. See overlapping longitudinal study and sequential research design.

LOS Late onset schizophrenia.

loudness recruitment Problem found in some forms of hearing impairment in which sounds in certain frequency bands are (mis)perceived as being louder than normal, sometimes to the point of being painful.

LTM long-term memory.

macular degeneration Degeneration and ultimately loss of the eye’s ‘yellow spot’ or macula, which is responsible for the highest resolution of focus in the eye.

mad cow disease Bovine spongiform encephalopathy magnetic resonance imaging (MRI scan) Method of obtaining cross-sectional or three-dimensional images of body parts (including the brain). Essentially works by detecting the resonance of cell molecules in a magnetic field and extrapolating an image from these.

manic depression Bipolar disorder.

matching (participants) Process of ensuring that groups of participants have equivalent scores on certain essential measures, thereby ensuring that any group differences found on other tests are not due to differences on the measures which have been matched. For example, if groups of older and younger adults have been chosen for identical scores on intelligence tests, and an age group difference is then found on Test X, then this difference cannot be due to differences in intelligence, but must be due to something else (e.g. age).

ME Molar equivalence.

ME-MD strategy See molar equivalence.

memory span The longest list of items which a participant can reliably remember. Researchers vary in their interpretation of ‘reliably’, e.g. some hold that span is the

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longest list length consistently remembered, others that it is the length remembered on 50 per cent of occasions.

memory trace The storage of memory.

mental capacity The limit on how much information a mind can process at any one time, and/or how quickly it can process information.

Mental Status Questionnaire (MSQ) Devised by Kahn et al. (1960), a simple gauge of a (usually demented) patient’s intellectual status and degree of functional independence. See Blessed Dementia Scale.

metaknowledge A person’s understanding of the quantity and accuracy of what he or she knows.

metamemory A person’s knowledge about their own memory abilities.

method of loci A technique for improving memory. Participants imagine a familiar scene and juxtapose images of to-be-remembered items onto it. By taking a ‘mental walk’ through the scene, participants should be able to remember the items.

MID Multi-infarct dementia.

Mill Hill Vocabulary Test A measure of vocabulary – the test requires participants to provide definitions of words, whose obscurity increases as the test progresses (there is no time limit).

Mini Mental State Examination (MMSE) A quickly-administered assessment of the general intellectual state of a patient. Questions include measures of orientation for time and place, basic tests of short-term memory, and ability to name common objects.

Minnesota Multiphasic Personality Inventory (MMPI) Personality test, yielding scores on ten scales, which are indices of (principally abnormal) personality traits.

MMPI Minnesota Multiphasic Personality Inventory.

MMSE Mini Mental State Examination.

mnemonic (a) Memory aid; (b) more generally, pertaining to memory and its workings.

molar equivalence (ME) A molar skill is one which can be broken down into a number of sub-skills ( molecular decomposition). If a molar skill is performed equally well by groups of differing ages, then ‘molar equivalence’ is said to have occurred.

However, a skill is performed equally well but some of the sub-skills are performed better by some groups than others, then an ME-MD strategy (or compensation) has occurred.

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molar skill See molar equivalence.

molecular decomposition See molar equivalence.

morphology Strictly speaking, the science of form. More generally, an awareness and knowledge of word meanings and word structure.

motor (neurons) Carrying signals from the central nervous system to skeletal muscle.

motor skills Ability to control bodily movements. ‘Fine motor skills’ describes control of relatively delicate movements, such as manual dexterity.

MRI scan Magnetic resonance imaging.

MSQ Mental Status Questionnaire.

multi-infarct dementia Form of dementia characterised by the brain suffering a large number of infarcts. Patients typically suffer a stepwise rather than progressive decline.

multiple regression Statistical technique for predicting the value of a variable given the value of several others. The technique can also be used to see which variable of several is the best predictor of another variable and whether once the best predictor’s performance has been taken into account, the remaining variables can add any further predictive value to the equation.

N Neuroticism.

naming latency The speed with which a new word can be read aloud.

NART National Adult Reading Test.

National Adult Reading Test (NART) A list of words, most with irregular spellings, which participants must read out loud (i.e. pronounce).

need for cognition A measure of the drive to pursue intellectually-demanding tasks.

negative correlation A value of r falling below zero and greater than –1. In other words, a relationship in which as one variable increases in value, the other declines (e.g. number of sweets eaten and desire to eat more). See correlation.

nerve See neuron.

neural noise Concept that neural signals lose some of their fidelity because of interfering signals from neighbouring neurons (loosely, akin to poor radio reception because of interference from other stations). This is assumed to increase in later life, making mental processing less efficient, and hence lowering intellectual ability.

neuritic plaque Senile plaque.

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neurofibrillary tangles (NFT) Clumps of dead brain neurons which (under a microscope and with some artistic licence) look like knotted string. Common feature of the brains of patients with dementia of the Alzheimer type.

neuron/neurone An individual ‘nerve’ or ‘nerve cell’ (strictly speaking, a nerve is a collection of neurons forming a common path for sending messages in the peripheral nervous system; a similar structure in the central nervous system is called a tract).

neuroticism As used in this book a personality trait from Eysenck’s personality model. Generally, neuroticism measures how anxious and emotionally unstable a person is.

neurotransmitters Chemicals transmitted between neurons at synapses, and hence the means by which neurons communicate with each other.

new learning deficit Relative difficulty in learning new information, in comparison with older information and/or another group of people. Used by some commentators to describe the relative weakness of older people in learning a new piece of information and/or task.

NFT Neurofibrillary tangle.

NINCDS-ADRDA criteria A set of criteria for evaluating the probability that a patient is suffering from dementia of the Alzheimer type. The initials refer to the organisations who jointly devised the scheme. It provides a diagnosis of ‘probable’, ‘possible’ or

‘definite’.

noise in nervous system Neural noise.

noradrenaline A neurotransmitter.

noradrenergic system Network of neurons using noradrenalin as their neurotransmitter.

Primarily used in the control of smooth muscle.

normal distribution A distribution of scores/measurements which has a characteristic bell-shaped curve with a peak above the horizontal axis, and which is symmetrical about its vertical midpoint. The peak of the curve represents the mean (i.e. average), median (the score which is bigger than 50 per cent of the values represented by the curve), and the mode (the commonest score). Because the distribution is found for many types of measurement, it is termed ‘normal’ and many types of statistical test are predicated on the assumption that data are drawn from normally distributed populations.

normal pressure hydrocephalus Caused by a failure of cerebrospinal fluid to drain away, leading to a destructive pressure on brain tissue. The complaint can lead to dementia.

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normative age-graded development See Balte’s theory of lifespan development.

normative history-graded development See Balte’s theory of lifespan development.

Nun Study A longitudinal study of a group of American nuns who have agreed to be tested on a battery of psychological and medical tests each year, and on death have agreed that their brains will be made available for autopsy.

nvCJD See Creutzfeldt-Jakob Disease.

Object Memory Evaluation (OME) Measure of memory for objects at different gaps of time and employing learning trials.

observer memory The phenomenon that one’s distant autobiographical memories are usually recalled as if one were a bystander.

obsessive-compulsive disorder See anxiety disorder.

obsolescence effect Theory that some of age-related deterioration may be because older people’s memories may no longer be attuned to the contemporary world (i.e. are obsolete rather than lost).

occipital lobes Regions of the cerebral cortex roughly in the region of the back of the head. Their principal function is in vision.

old age dependency ratio The number of people aged 60 and over divided by the number aged 20–64. This gives an indication of the proportion of people drawing pensions and other welfare and health benefits to those in employment who will be the principal financial supporters of this through taxation.

old elderly Most commonly defined as those people aged over 75 years (though note commentators differ over the precise figure). See young elderly.

OME Object Memory Evaluation.

ondansetron Drug whose effects include the enhanced release of acetylcholine (see cholinergic hypothesis) and thus a potentially beneficial treatment of some forms of dementia. See ganglioside and tacrine.

ordered recall A memory task in which items have to be recalled in exactly the order in which they were originally presented. Compare with free recall.

overlapping longitudinal study Type of longitudinal study in which several age cohorts are tested at regular intervals on the same body of tests. Cross-cohort comparisons can be made at each test session (as in a cross-sectional study); ageing change within the same individuals can be measured (as in a longitudinal study), and by comparing performance of different cohorts as they reach the same age at different calendrical times, it is possible to assess the strength of cohort effects.

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P Psychoticism.

paired associate learning Remembering which item was previously presented with which (e.g. the participant sees the words cat and briefcase presented together, and later when shown cat must recall briefcase).

panic attack See anxiety disorder.

panic disorder See anxiety disorder.

parietal lobes The region of the cerebral cortex which occupies an area contiguous with an Alice band (or headphones strap) across the head. Their role is hard to define concisely, but they can be said to be involved in maintaining an awareness of the body’s state and location, and in interpreting symbols.

Parkinsonian dementia Dementia in which Parkinsonism is present.

Parkinsonism Set of symptoms, including a shuffling gait and trembling hands, bradykinesia and hypokinesia, found in Parkinson’s Disease and also in several other brain disorders, including some of the dementias.

Parkinson’s Disease (PD) Illness caused by a decline in the substantia nigra (an area of the brain responsible for producing dopamine). Characteristic symptoms are known collectively as Parkinsonism.

partial correlation A statistical technique for assessing how much of the correlation between two variables is due to the co-incidental effect of a third variable (the removal of whose influence is known as partialling out).

partialling out See partial correlation.

passive-dependent personality Personality type identified by Neugarten et al.’s (1961, 1968) studies. Possessors of this type rely on others to help them ( succourant seeking) or withdraw from human interaction as much as possible ( apa-
thetic).

passive euthanasia Allowing someone to die by not administering life-saving or life-prolonging treatment.

patient cohort Group of patients with not only an illness in common but also a set of attitudes (e.g. feeling ‘unhealthy’). Compare with disease cohort.

Pattison’s stages of dying Psychological stages which a dying patient passes through according to E.M. Pattison (1977). (1) acute crisis phase – great anxiety upon realising that death is imminent. (2) chronic living-dying phase – a period of mourning for what is being lost. (3) terminal phase – an inward withdrawal and resigna-tion/acceptance. See Kubler-Ross’s stages of dying.

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PD Parkinson’s Disease.

PDD Primary degenerative disorder.

peg board task Several variants of this task, but all have the central feature of requiring the participant to put pegs into holes as quickly as possible.

peripheral nervous system (PNS) Neurons connecting the central nervous system to the rest of the body.

perseverations Inappropriate repetition (e.g. repeating the same phrase or keeping at a particular problem-solving strategy after it has been demonstrated to be inappropriate).

personality ‘The individual characteristics and ways of behaving that, in their organisation or patterning, account for an individual’s unique adjustments, to his or her total environment’ (Hilgard, Atkinson and Atkinson, 1979).

personality trait An enduring characteristic of personality which is hypothesised to underpin all or most behaviour.

PET scan See positron emission tomography.

PHI Profound hearing impairment.

phobia See anxiety disorder.

phoneme The smallest unit of speech whose substitution or removal from a word causes a change in the word’s sound. More loosely, the basic sounds which make up words (and even more loosely, the verbal equivalent of letters).

phonological Pertaining to phonemes.

phonological loop Slave system in the working memory model responsible for the temporary storage of any information capable of being stored phonologically.

phonology Strictly speaking, the study of phonetics. Sometimes used to denote a person’s awareness and understanding of phonological structure.

physiological age Biological age expressed through the state of the body’s physiological processes, such as metabolic rate. See anatomical age.

Piagetian conservation tasks A series of tests (named after their inventor, Piaget) intended to demonstrate the illogicality of children’s thought processes.

Piaget’s ‘kidnapping’ Anecdote by Piaget (the famous developmental psychologist) illustrating the fallibility of autobiographical memory. Piaget had a distinct memory of a kidnap attempt on himself when aged two years, which his nurse successfully repulsed. Years later, he discovered that the nurse had invented the whole episode,

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and therefore his memory was an elaboration of her story, rather than recall of a real event.

Pick’s bodies Damaged neurons, found in Pick’s disease patients, and possessing a characteristic swollen appearance.

Pick’s disease A form of dementia characterised by a progressive deterioration of the frontal lobes and other sub-cortical areas of the brain. Psychologically, there are often disturbances in personality before intellect or memory.

PMA See Primary Mental Abilities Test.

PNS Peripheral nervous system.

positive correlation A value of r greater than 0 and less than 1. In other words, a relationship where as one variable increases, so does another. See correlation.

positron emission tomography An electronic scanning method which measures how a section of the body (in the context of this book, typically the brain) metabolises a (mildly radioactive) tracer injected into the blood. This gives an indication of the relative level of activity, and by implication, health, of the area of the body being surveyed.

post-developmental A phrase used by some gerontologists to denote that changes in later life are often detrimental rather than developmental and/or beneficial.

postformal thought Theory that in adulthood, people develop the ability to combine subjective and objective criteria in resolving a problem. The term refers to the concept that it develops after formal operations.

potential lifespan Lifespan.

pragmatics The understanding of the intent of an utterance rather than its literal interpretation. More generally, the ability to grasp the most satisfactory solution rather than the one which is necessarily logically correct.

pre-morbid IQ The IQ level (usually estimated) of a person before the onset of an illness (usually one which has affected the intellect, such as dementia).

pre-senile dementia Dementia whose onset is before the patient’s sixtieth birthday.

presby- Prefix denoting old or ageing.

presbyacusis Presbycusis
presbycusis Hearing loss which worsens with ageing, and typically characterised by loss of ability to hear high frequency sounds.

presbyo- Presby-

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presbyopia Inability to focus on near objects.

preserved differentiation Theory that some skills are better preserved than others in later life because they have always been better. The argument is implausible for the general population, but may be feasible for specific samples of the population with very specialised skills (e.g. professional musicians).

primary ageing Age changes which all older people can expect to experience to some degree (e.g. skin wrinkling). See secondary ageing and universal ageing.

primary degenerative disorder (PDD) Dementia of the Alzheimer Type.

primary memory Short-term memory.

Primary Mental Abilities Test An intelligence test battery devised by Thurstone.

primary vascular dementia Multi-infarct dementia.

priming In memory experiments, providing hints about features of the items a participant is trying to recall.

prion disease Group term for a range of degenerative brain disorders, such as bovine spongiform encephalopathy and Creutzfeldt-Jakob disease, which some commentators believe are due to an abnormal protein metabolism. ‘Prion’ is an abbreviation of

‘proteinaceous infectious particle’.

probabilistic ageing Aspects of ageing likely to affect most (but not necessarily all) older people (e.g. cardiovascular problems). Similar to secondary ageing. See universal ageing.

processing resources theory of ageing Any theory which argues that changes in ageing intellectual skills are attributable to a lowered capacity for mental calculations (e.g. of working memory), lowered speed of processing, etc.

profound hearing impairment (PHI) Hearing impairment of > 90 dB.

progeria Disease characterised by the symptoms of abnormally rapid ageing (patients typically die in their teens).

programmed senescence Belief that the body is genetically programmed to age, usually with the implication that this is the result of evolutionary pressure. See programmed theory of ageing.

programmed theory of ageing Theory that cells may be predestined to die because of inbuilt faults in the replication system (see, e.g. Hayflick limit). Not to be confused with programmed senescence, which more often denotes that these problems are the result of evolutionary pressure.

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progressive (illness) Description of an illness in which the symptoms appear and then get worse over time.

progressive supranuclear palsy (PSP) Illness characterised by disturbances of motor function and mild to moderate dementia.

prospective memory The ability to remember to do something in the future.

proverb interpretation Measure of the understanding of the meaning of proverbs (e.g.

Gorham Proverb Interpretation Test). Patients in the early stages of dementia may give very literal interpretations of proverbs meant to be taken at symbolic value (e.g. ‘a rolling stone gathers no moss’).

proximal ageing effects Ageing changes directly attributable to changes in another process (e.g. a stroke). Compare with distal ageing effects.

pseudodementia Severe lowering of cognitive abilities to dementia-like levels caused by severe depression in some older patients.

PSP Progressive supranuclear palsy.

psychogenic mortality Psychological factors leading to physical symptoms which in turn cause death.

psychogerontology The study of the psychology of ageing.

psychological age A person’s psychological state compared to that of an average person of the same chronological age.

psychometrics Strictly speaking, the measurement of psychological traits and skills, but more generally, the study of psychological differences.

psychomotor skill A physical skill in which there is a strong component of intellectual prowess or vice versa.

psychotherapy Any treatment regime based on an integrated theory of mind.

psychoticism A personality trait in Eysenck’s personality model measuring the degree of emotional ‘coldness’ a person possesses.

pugilistic dementia Dementia induced by repeated blows to the head, often over some period of time (has been observed in some older boxers, hence the name).

pyramidal society Society in which there are far more younger than older people (the population can be envisaged as successively smaller age groups stacked one on top of another, forming a pyramid). This contrasts with a rectangular society, in which there are roughly equal numbers of people in each age group (and hence the layers stacked on each other look more like a rectangle than a pyramid).

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quality ratio In studies of creativity, the ratio of good to indifferent or poor works produced by a person within a particular time period.

r Symbol for correlation.

RAGS Relatives’ Assessment of Global Symptomatology.

Raven’s Progressive Matrices A test of fluid intelligence, in which participants are given a series of problems (against the clock) which have a common theme of a logically-governed sequence from which one member is missing (the participant must find the missing member from a set of choices).

raw score The actual score on a test, as opposed to an adjusted or weighted figure, such as the intelligence quotient.

re-engagement theory Activity theory.

reaction time (RT) Time taken for a person to respond to the appearance of a stimulus.

See choice reaction time and simple reaction time.

recall The ability to remember items in memory without any prompting. See ordered recall and free recall.

recognition The ability to identify which items have been previously encountered when given a list of alternatives to choose from.

rectangular society See pyramidal society.

rectangular survival curve Hypothesised graph of percentage of survivors in an age cohort in a future of very effective medical care. By this reckoning, very few people will die until their lifespan is reached, when most will die within a few years of each other. A graph of the percentage of the age cohort alive at different ages (with percentage of the vertical axis and age on the horizontal) would thus look rectangular.

reflex arc A simple connection between afferent and efferent neurons in the spinal cord.

The mechanism is responsible for several reflexes (e.g. the famous knee jerk reflex).

regression Statistical technique predicting the value of one variable from the value of another. See multiple regression.

regression hypothesis Theory that older people’s linguistic skills revert to the qualitative state of a child’s.

rehearsal (memory) The process of repeating to-be-remembered items ‘in the head’ in an effort to remember them better.

Relatives’ Assessment of Global Symptomatology (RAGS) Questionnaire measure of symptoms of the patient observed by his/her caregivers.

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reminiscence bump Reminiscence peak.

reminiscence peak Phenomenon that the bulk of autobiographical memories stem from when people were 10–30 years old.

remote grandmother See Robertson’s taxonomy of grandmothers.

remote memory Memory for non-autobiographical events which have occurred during a person’s lifetime. A frequent proviso is that these events must exclude famous incidents which have been aired in the media so often that they are part of general knowledge.

reorganisers See integrated personality.

reversible dementia An illness which produces symptoms of dementia, but which can be cured and in the process reverse or at least lessen the dementing symptoms.

reversible dementia of depression Pseudodementia.

Ribot’s hypothesis Theory that in damaged or decaying mental systems, memories for recent events are worse than memories for remote events.

Rivermead Behavioural Memory Test Set of memory tasks analogous to everyday situations where memory is required (e.g. face recognition, remembering a route).

Robertson’s taxonomy of grandmothers J.F. Robertson (1977) categorised grandmothers into four types: (1) apportioned grandmother – has both a social and a per-
sonal set of expectations for her grandchildren; (2) symbolic grandmother – has a social set of expectations; (3) individualised grandmother – has a set of personal expectations; (4) remote grandmother – relatively detached from the whole idea of being a grandmother.

rocking chair personality See Dependent personality.

RT Reaction time.

Roseto effect The effect on health of changing a lifestyle. Named after an Italian–

American community in Roseto, Pennsylvania, whose susceptibility to heart disease increased as it became more ‘Americanised’.

SAD Subcortical arteriosclerotic dementia.

SATSA Swedish Adoption/Twin Study on Ageing.

schema Collection of memories about an event or item which enable one to plan responses and to interpret information surrounding the said event or item.

schizophrenia A profound disorder of thought, perception and language in the absence of mental retardation, characterised by a severe distortion of perception of

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reality and concomitant changes in emotions and behaviour. There are various forms of the illness, each with a distinct set of symptoms. The commonest of these symptoms include irrational beliefs about the way the world functions, often with a central theme that the patient is being persecuted. There may also be hallucinations (such as ‘voices in the head’). Language can often be best described as ‘surreal’, with unusual expressions and ideas and invented words.

Seattle Longitudinal Aging Study Longitudinal study of psychological ageing, run by K.W. Schaie and colleagues. The first participants were tested in 1956, and have been retested (along with new cohorts of participants) at regular intervals ever since.

secondary ageing Age changes associated with, but not necessarily an inevitable consequence of, ageing (e.g. arthritis). See primary ageing and probabilistic ageing.

selective attention The ability to attend to one stimulus set against distracting stimuli.

self-hatred personality Personality type identified by Reichard et al. (1962) characterised by unrealistic self-blame for misfortune.

semantic Pertaining to meaning.

semantic deficit hypothesis Model of ageing which argues that age-related deficits in intellectual functioning are attributable to a failure adequately to process incoming items (e.g. items to be memorised) for the information they contain.

semantic facilitation Phenomenon that items are identified faster if preceded by items related in meaning (e.g. ‘bread’ is identified faster if the participant has just seen

‘butter’ as opposed to ‘car’).

semantic memory Memory for facts; compare with episodic memory.

semantic priming Semantic facilitation.

senescence Later life, with the implication of ageing free from dementia and other impairments of psychological functioning.

senescing Ageing in terms of biological age.

senile Medical term for ‘old’; NEVER to be used as a synonym for later life.

senile dementia See dementia.

senile plaque (SP) Amorphous clumps of dead neurons found in high concentrations in the brains of some patients with dementia.

sentential grouping A (typically inefficient) method of classifying objects on the grounds that they can be included in the same sentence or story.

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sequential research design Longitudinal study in which different age cohorts are tested at intervals over several years. In addition, age cross-sections of the population are tested in tandem with the longitudinal test panel, to gain an insight into possible cohort effects.

SETOF Speed-error-tradeoff function.

short term memory Temporary memory for events which have occurred in the past few seconds/minutes. Has a limited capacity (typically between 5 and 9 items, depending upon the task and the individual), is easily disrupted and items are quickly forgotten unless a conscious effort is made to remember them. See long- term memory and working memory.

silent stroke Stroke which produces no symptoms, and is only discovered by either a brain scan or at autopsy. The term is sometimes used to describe a stroke which is unnoticed at the time of occurrence, but which subsequently causes a significant alteration in behaviour or functioning.

simple reaction time (SRT) Time taken to respond when there is only one choice of response to the stimulus. See choice reaction time.

slave systems Term derived from computing to denote systems (usually capable of one type of operation only) which cannot operate unless under the command of a master controller.

SOA Stimulus onset asynchrony.

social age A set of behaviours and attitudes considered to be socially appropriate for the chronological age of the individual.

social clock Hypothesised mechanism which an individual ‘consults’ to determine the most appropriate behaviour for his/her social age.

somatic (peripheral nervous system) Information from joints, skin and skeletal muscle transmitted to the central nervous system.

somatic mutation theory of ageing Theory that as cells are lost through natural ‘wear and tear’ they are replaced by imperfect copies because of genetic errors, and thus are less likely to function efficiently. See autoimmune theory of ageing, disposable soma theory of ageing, free radical theory of ageing and Hayflick phenomenon.

SP Senile plaque.

span Abbreviation of memory span.

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speed-error-tradeoff function (SETOF) Measure of the degree to which an individual is prepared to trade speed at performing a task (i.e. slow down) in order to reduce the number of errors made. A measure often used in reaction time experiments.

speed hypothesis General slowing hypothesis.

spinal cord The principal meeting point between peripheral and central nervous system neurons.

SRT Simple reaction time.

standard deviation Statistical measure used, inter alia, to indicate the range of scores in a sample. A useful rule of thumb is that for a normal distribution the range of scores between the mean minus two standard deviations and the mean plus two standard deviations accounts for approximately 95 per cent of the sample’s scores.

stimulus onset asynchrony (SOA) In a backward masking experiment, the difference between the length of time the to-be-remembered item has to be presented alone and the length of time it has to be presented when it is followed by a mask for it to be correctly recognised.

STM Short-term memory.

stroke Damage to brain tissue caused by the cessation of its blood supply. The psychological effect of the stroke depends upon the location of the injury.

subcortical Pertaining to the areas of the brain other than the cerebral cortex.

subcortical arteriosclerotic dementia (SAD) Vascular dementia whose primary damage occurs in regions of the brain other than the cortex.

subcortical dementia Dementia whose principal focus of damage is not in the cerebral cortex.

subdural haematoma Blood clot in the brain. See cerebral haemorrhage.

successful ageing Rather nebulous term describing (1) older people whose lifestyles are successful, or at least trouble-free and/or (2) more specifically, the retention of youthful levels of performance of the skill in question.

succourant-seeking See passive-dependent personality.

sundown syndrome The phenomenon observed in some patients with dementia, who get up during the night and wander about, without regard for the propriety of the time or place. See wandering.

superego In Freudian theory, a person’s set of (often over-harsh) moral dictums. See ego and id.

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supraspan learning Learning lists of items whose number exceeds one’s memory span.

survival curve Graph plotting the numbers of people within an age cohort still living at different ages.

survivors Members of an age cohort who have lived past a particular age.

sustained attention The ability to concentrate on a set task without being distracted.

Swedish Adoption/Twin Study on Ageing (SATSA) Longitudinal study, commenced in 1979, of Swedish identical and non-identical twins reared apart or together.

symbolic grandmother See Robertson’s taxonomy of grandmothers.

synapse The junction between two neurons, in the form of a microscopic gap across which neurotransmitters can be sent.

syntax Grammar.

tacrine Drug whose effects include the enhanced release of acetylcholine (see cholinergic hypothesis), and thus a possible treatment for some forms of dementia.

talking book Cassette or other audio recording of a person reading a book. Most talking books are readings of edited versions of the originals to keep the size of the package down to one or two cassettes, discs, etc.

target (1) In recognition tasks, the item which has been previously encountered and which must be distinguished from any distracters present; (2) in attention tasks, the item to be located from amongst the distracters.

TBR To-be-remembered.

telomere Section of DNA felt to be involved in ageing. When a cell duplicates itself, the length of the telomere is shortened; after several duplications, it reaches its shortest length and cell duplication can no longer take place.

temporal lobes Section of the cerebral cortex occupying (roughly speaking) the areas of the right and left temples. Chief function is in interpretation of information; in most people, the left temporal lobe is essential in language comprehension and production. Also strongly involved in the storage of memory.

terminal drop model The theory that in older individuals, there is a sudden and marked decline in intellectual skills a few months/years before their death.

terminal phase (of dying) See Pattison’s stages of dying.

tertiary ageing A rapid deterioration during dying.

tertiary memory Remote memory.

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test battery A group of tests designed to assess the same skill (e.g. intelligence).

test wise The condition of becoming attuned to the general design of psychological tests (particularly intelligence tests), and improving in performance as a result. The phenomenon usually arises from using the same panel of volunteers too often, thereby artificially elevating their apparent skills. The problem is of particular concern in longitudinal studies.

thalamus Area of brain co-ordinating and channelling information and executing motor movements. Damage to this area is heavily involved in Parkinsonism.

thanatology The study of death and dying.

theta waves A pattern of electrical activity detected by EEG with a frequency between 4
and 8 Hz.

third age Active and independent later life. Contrast with fourth age.

threshold age The chronological age which (arbitrarily) denotes the division between one age group and another.

threshold model of dementia The theory that individuals have a genetically-fixed predisposition to develop dementia, but whether they actually do depends upon a trigger in the environment. In people with a low predisposition, a large environmental input is required, and vice versa.

thrombosis Blood vessel blocked due to clotting.

time-based task In prospective memory experiments, a task requiring a response which must be self-initiated at the appropriate time.

time-lag comparison Comparing different age cohorts at the same age in a longitudinal study.

time-lag effect Cohort effect.

time-sequential design An ‘extended’ cross-sectional study design now generally no longer practised. Two or more groups are compared at one time period, and then several years later, different participants are tested, who are the same ages as the participants were in the original study.

tinnitus A hearing complaint characterised by a (usually permanent) irritating noise (often akin to a ‘ringing in the ears’, and sometimes painful) which interferes with normal hearing.

tip of the tongue (TOT) Phenomenon of recalling features of an item (e.g. what it sounds like, number of syllables, and so forth) but not its identity. Often induced in

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experiments by providing people with the definition of a word and asking them to name it.

to-be-remembered (TBR) Items in a memory task which the participant is asked to remember.

TOT Tip of the tongue.

tract See neuron.

Trail Making test Sub-test of the Halsted-Reitan Neuropsychological Battery, assessing ability to follow sequences. The participant must make a pencil trail between particular numbers (or in another version, numbers and letters) printed on a sheet of paper.

transient ischaemic attack Stroke whose effects are usually relatively trivial, and are gone within 24 hours.

triple jeopardy Term illustrating that older people facing double jeopardy often also face a third problem of prejudice and/or communication problems barring them from the help they need and deserve.

Type A personality A personality type prone to being competitive and ‘hard edged’.

Contrasts with Type B personality, which is prone to being (over)easy-going and relaxed.

Type B personality See Type A personality.

two-factor theory of well-being In essence, the theory that positive events tend to influence the positive aspects of one’s mood and negative events the negative aspects of one’s mood.

Ulverscroft large print series Series of popular books in large print size intended for people with visual impairments. Traditional patrons are older users of public librar-ies.

universal ageing Aspects of ageing held to affect everyone who reaches later life (e.g.

wrinkling skin). See probabilistic ageing.

VaD Vascular dementia.

vascular dementia (VaD) Dementia caused by damage to the blood vessels within the brain.

verbal span Memory span for words.

view from the bridge Title of an Arthur Miller play. Also, in Levinson’s theory, the desired state in late life when older people have come to terms with their past.

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viscera Intestines.

visual agnosia Inability to recognise objects by sight.

visual search task Test of selective attention. The participant must find a target item which is located in an array of distracter items.

visuo-spatial Pertaining to visual appearance and spatial characteristics (e.g. where items in a display are relative to each other).

visuo-spatial memory The ability to remember visual and/or spatial information.

visuo-spatial sketchpad A slave system of the working memory model: a temporary store of visuo-spatial information.

WAIS See Wechsler Adult Intelligence Scale.

wandering (dementia) Nebulous term describing any inappropriate walking behaviour. This can manifest itself as part of hyperactivity, but may also describe walking about apparently aimlessly or ‘wandering off ’ on a walk for no apparently obvious reason (see also sundown syndrome).

wear and tear theory Theory of ageing that parts of the body gradually ‘wear out’

with use. Compare with cytologic theory.

Wechsler Adult Intelligence Scale (WAIS) Intelligence test battery covering all commonly assessed areas of intelligence.

Wechsler Memory Scale Memory sub-tests from the Wechsler Adult Intelligence Scale.

Werner’s syndrome Extremely rare disease with onset in teens (though first symptoms may not become ‘obvious’ for some years) characterised by accelerated physical ageing, notably the skin, hair and cardiovascular system. Death is typically in the forties.

Wernicke’s aphasia Specific failure to understand speech, resulting from brain damage.

Wernicke’s dementia Dementia caused by vitamin deficiency (particularly Vitamin B).

Often there is an associated motor impairment.

Wisconsin Card Sorting Task Measure of hypothesis formation and the ability to reject or not persevere with an invalid one. Participants must discover the correct rule for matching up cards of different patterns and colours (e.g. a yellow card must always be matched with a red card). Once participants have discovered the correct rule, the experimenter changes it, and how quickly the participants stop using the old rule and search for the new one is measured, as well as how quickly they solve

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the new problem. Abnormally persevering with an old rule can be indicative of brain damage, particularly to the frontal lobes.

wisdom Somewhat nebulous concept, with several separate though related definitions, depending upon the researcher in question. Most agree in essence that it refers to an ability to judge and resolve real life problems which require a balance of logical and pragmatic factors, tempered by experience. However, within this broad remit, individual authors have used the term loosely, ranging from a synonym of crystallised intelligence to psychoanalytic theories.

word completion task Task in which the participant is required to complete a word given the first letter(s).

word span Memory span for words.

working memory Popular and influential model of short-term memory, first described by Baddeley and Hitch (1974). The model argues that short-term memory is controlled by a central executive, which delegates memory tasks to specialist slave systems, principally the phonological loop and visuo-spatial sketchpad.

Yngve depth An analytic technique which gives a ‘score’ for the syntactic complexity of a sentence or phrase.

young elderly The commonest definition is the age group between 60 and 75 years (though lower and higher boundaries are not unknown). See old elderly.

young-old plot Plotting a graph of the performances of younger adults against older adults on the same task. Best known example is the Brinley plot.

zeitgeist Spirit of the (historical) age.

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