The maturation of personality psychology: Adult personality development and psychological well-being
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The maturation of personalitypsychology: Adult personality
development and psychological well-being
Robert R. McCrae
Laboratory of Personality and Cognition, Gerontology Research Center NIA, NIH,
Box No. 03, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825, USA
Personality psychology has made striking advances in the past two decades, dem-
onstrating the importance of individual dierences in a wide variety of life domains.
Longitudinal studies of adult development contributed to these advances by reveal-
ing the stability of personality traits even in the face of changing life circumstances.
More recently, cross-culturally replicated patterns of adult age dierences have sug-
gested that traits are endogenous dispositions with intrinsic paths of development.
The importance of personality traits was underscored by research linking dimensions
of personality to psychological well-being and mental health, and the rapidly matur-
ing science of personality psychology holds promise for understanding many other
social and psychological phenomena.
Twenty-ve years ago most personality psychologists knew next to noth-ing about adulthood, and researchers interested in morale and life satisfac-tion knew next to nothing about personality they thought they would ndall their answers by asking about income, housing conditions, and healthcare availability. For that matter, 25 years ago personality psychologistswho used the Eysenck Personality Inventory (Eysenck & Eysenck, 1964)
Journal of Research in Personality 36 (2002) 307317
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hardly spoke to personality psychologists who used the MMPI (Hathaway& McKinley, 1943).
There had by then been a good deal of rst-rate personality research.There were longitudinal studies by Kelly (1955) and by Kagan and Moss(1962). Bradburn (1969) had done groundbreaking work on psychologicalwell-being. Factor-analysts had conducted hundreds of studies of personal-ity structure (e.g., Eysenck, White, & Soueif, 1969). But in some respectsthere was no real science of personality psychology no organized bodyof knowledge. Today there is, in the form of a generally accepted modelof personality traits that are rooted in biology, that endure through adult-hood, and that inuence an extraordinary range of psychological processesand outcomes. Personality psychology is much more than trait psychology,but traits form the core of our knowledge about who persons are and whyand how they act.
And as a result of this knowledge, there has begun to be a profound shiftin psychologys center of gravity or its locus of control from outside toinside the person. During most of this century, the causes of behavior andexperience were sought in the environment. We presumed that personalitywas distally shaped by culture and proximally shaped by the child-rearingpractices of parents. We thought that psychopathology was the result of lifestress, and that events such as marriage, retirement, and loss of spousewould surely bring about major transformations of intraspychic and inter-personal styles. We thought we would be happy if we won the lottery.
We now know that these assumptions are nave, just to the extent thatthey leave out of account the contributions of the individual (cf. Neyer& Asendorpf, 2001). The same structure of personality recurs in culturesas distinct as those of Portugal, Croatia, and South Korea (McCrae &Costa, 1997). Parentchild relations reect the temperament of the childas well as the ideology of the parent (Halverson & Wampler, 1997). Reac-tions to stress say as much about the stressed as about the stressor (McCrae,1990). Personality traits remain largely unchanged despite the vicissitudes oflife experience (Costa & McCrae, 1997). And money, it turns out, cannotbuy happiness (Brickman, Coates, & Jano-Bulman, 1978). In some veryprofound ways, personality traits transcend environmental inuences, andgerontologists and social scientists from many elds need to include person-ality traits in their research, more often as independent than as dependentvariables.
2. Adult personality development: stability and change in individual dierences
Contemporary trait psychology has been profoundly inuenced by nd-ings from a series of longitudinal studies (e.g., Helson & Kwan, 2000; Siegleret al., 1990) that have revealed the natural history of personality traits. The
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basic nding is simply stated: individual dierences in personality traits areextremely stable in adults, even over periods of as long as three decades. Un-corrected retest correlations of .70 are not uncommon over that interval;corrected for unreliability, these values can approach unity. Research con-tinues on the details (e.g., when maximum rank-order stability is attained;Roberts & DelVecchio, 2000), but the overall conclusion of predominantstability is not in dispute (Costa & McCrae, 1997).
The demonstration of stability was important in the recent history of per-sonality psychology because it provided an eective answer to critics whoclaimed that personality traits were at best weak determinants of any specicinstance of behavior (Mischel, 1968). True; but because they endure for de-cades, the cumulative inuence of traits on peoples lives can be very great,as a few researchers have documented (e.g., Soldz & Vaillant, 1999).
Longitudinal studies have also proven particularly informative by dem-onstrating the relative imperviousness of personality traits to life experi-ences. Over the course of three decades, most people will haveexperienced major life changes in their families, friendships, jobs, andhealth. That all ve personality factors (Neuroticism, Extraversion, Open-ness, Agreeableness, and Conscientiousness) nevertheless remain largely un-changed suggests that personality traits are not learned adaptations, butbiologically based endogenous dispositions (McCrae et al., 2000).
From that perspective it is not surprising that the most dramatic andbest-documented changes in personality are those associated with changesin the brain, attributable to Alzheimers disease or to traumatic brain injury(Costa & McCrae, 2000). In contrast, eorts to nd moderators of stabilityassociated with normal life experience, or subgroups of people especiallyprone to change, have been generally disappointing (McCrae, 1993). Somepeople perceive that they have changed a great deal in the past few years,but those perceptions usually are not supported by longitudinal records(Costa & MacCrae, 1989). Again, people who have experienced majorchanges in physical health, such as heart disease or cancer, are just as stableas those who have not (Costa, Metter, & McCrae, 1994).
Of course, some researchers have reported personality changes associatedwith environmental inuences (e.g., Costa, Herbst, McCrae, & Siegler, 2000;Helson & Picano, 1990; Roberts & Chapman, 2000). Intriguing as they are,it is dicult to assess these ndings. The causal direction is often ambigu-ous. For example, Roberts and Chapman (2000) found that marital tensionat age 52 was associated with declines in eective functioning between age 21and age 52, but marital tension at age 27 was not. From such data one mightargue that changes in personality were the cause, not the eect, of rolestrain. Most reports of environmental eects are from small studies (Helson& Picano, 1990; Roberts & Chapman, 2000) or from small subsamples with-in larger studies (Costa et al., 2000), and few if any have been replicatedacross dierent samples.
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But consider another example, where small sample size is not an issue.Twenge (2000) conducted a meta-analysis of Neuroticism measures admin-istered between 1952 and 1993, and concluded that there were large birthcohort eects, with increasing anxiety among later-born cohorts. In partic-ular, studies using the Taylor Manifest Anxiety Scale (TMAS; Taylor,1953) showed increases of d :41 for men and .52 (adjusted for type ofcollege) for women in the period from 1952 to 1967. Considering that thisanalysis combined 53 dierent samples, this would appear to be denitiveproof of a cohort eect on this personality trait. But most college studentsin 19521967 had been born between 1932 and 1947, and individuals fromthis same birth cohort had been the subjects of another large study. Costaet al. (1986) examined Neuroticism scores in a national probability sampleof 4969 men and women aged 3454. On the basis of Twenges (2000) nd-ings, one would hypothesize that the youngest participants would scoreabout one-half standard deviation higher than the oldest participants,but in fact there was no dierence at all. It is possible to reconcile thesetwo studies by assuming that individuals showed a longitudinal increasein Neuroticism between ages 34 and 54 that just oset the cohort-related de-cline, but that would contradict a large body of longitudinal studies thatshow small decreases in Neuroticism in this portion of the lifespan (e.g.,Costa et al., 2000). At present, the reported birth cohort eects are amystery.
Also largely unresolved are claims of personality changes associated withenvironmental inuences that are intense, sustained, or deliberately designedto induce change, including traumatic events (Engdahl, Harkness, Eberly, &Page, 1993), career opportunities and challenges (Kohn & Schooler, 1982),social movements (Agronick & Duncan, 1998), religious conversion(Paloutzian, Richardson, & Rambo, 1999), and, of course, psychotherapy(Lambert & Supplee, 1997; Santor, Bagby, & Joe, 1997). It is not yet clearhow large such changes may be and how long they endure. However, evensmall or transient changes may be of great personal and social importance,so this remains an issue well worthy of continued attention.
3. Adult personality development: maturational trends
The second major question that can be addressed by longitudinalstudies as well as by cross-sectional studies concerns mean level changes,increases or decreases of a trait shared by a group as a whole, either becauseof common maturational trends or because everyone has encounteredthe same shaping experiences. This is perhaps the most basic question instudies of development: what changes with age? Do people becomemore rigid, or wiser, or more introverted? And if so, is this a natural andmore-or-less inevitable process, or is it due to features of our culture and
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historical era that would not be widely generalizable to other places andtimes?
Psychologists and gerontologists have conducted hundreds of studies onthese issues, and the results are consistent and clear, at least descriptively.After age 18, Neuroticism, Extraversion, and Openness decline, and Agree-ableness and Conscientiousness increase (Costa & McCrae, 1994). But be-cause the research literature on this topic is overwhelmingly based onstudies of Americans conducted in the second half of the 20th century, itis debatable whether these mean level changes are intrinsic features of hu-man development, or whether they are responses to the particular condi-tions of one time and place. Researchers cannot choose the era in whichthey work, but they can vary the place, and cross-cultural research givesan entirely new perspective on personality development.
It is easy to see that studies conducted in other, especially non-Western,societies, speak to questions about cultural inuences on development.For example, it would not be surprising if we found that Asian adoles-cents, raised in cultures that make great social and educational demandson their children, reached levels of Conscientiousness found in adults ata much earlier age than their American counterparts. It is perhaps lessobvious that cross-cultural studies can also speak, at least in part, tohistorical inuences, and thus to cohort eects. This is true because dif-ferent countries have had dierent recent histories. Perhaps youngAmericans are low in Conscientiousness because they have been spoiledby living through a period of peace and auence. Not so the teenagers ofCroatia and Russia: They have seen conict and economic hardship, butalso the possibilities of personal and economic freedom. Perhaps as a resultCroatian and Russian adolescents are high in self-discipline and achieve-ment striving.
Only a few studies report cross-cultural comparisons of adult age dier-ences (e.g., McCrae et al., 1999; Helson & Kwan, 2000), but they cover morethan a dozen nations and yield very consistent results. In almost every cul-ture, there are cross-sectional decreases in Neuroticism, Extraversion, andOpenness, and increases in Agreeableness and Conscientiousness. McCraeet al. (1999) concluded from such data that these cross-sectional age dier-ences are not due to cohort or secular eects, but to true maturation, as nat-ural to the human species as the graying of hair, and probably attributableto genetic mechanisms, as McGue, Bacon, and Lykken (1993) proposed.Other investigators are not yet persuaded of this interpretation. Certainlyit would be better to have nationally representative samples instead of thesamples of convenience available to date; to have data from less industrial-ized countries than those studied so far; and to corroborate self-reports withobserver ratings. Ultimately we ought to employ longitudinal designs in dif-ferent cultures to see if age dierences are in fact paralleled by directly as-sessed age changes.
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4. Psychological well-being
When trait psychology was just beginning to recover from the dark agesof the 1970s, it got a signicant boost from the studies showing that person-ality traits were among the most potent predictors of psychological well-be-ing. Traits might not be very ecient at predicting specic behaviors inlaboratory settings, but they could predict a much more meaningful crite-rion years in advance: namely, whether people would feel happy or unhappyabout their lives as a whole. An article that appeared in the rst issue of thenew Personality Processes and Individual Dierences section of JPSP useddata from the Normative Aging Study to address several questions aboutpersonality and well-being (Costa & McCrae, 1980). It showed that:
(1) Alternative operationalizations of psychological well-being, includingmeasures of life satisfaction and aect balance, seemed to share a commoncore of meaning;
(2) This global happiness or well-being was related to chronic negative af-fect and chronic positive aect, which were themselves independent;
(3) Negative aect was associated with Neuroticism, whereas Positive af-fect was associated with Extraversion; and
(4) Although people r...