The present study used meta-analytic techniques (number of samples = 92) to determine the patterns of mean-level change in personality traits across the life course. Results showed that people increase in measures of social dominance (a facet of extraversion), conscientiousness, and emotional stability, especially in young adulthood (age 20 to 40). In contrast, people increase on measures of social vitality (a 2nd facet of extraversion) and openness in adolescence but then decrease in both of these domains in old age. Agreeableness changed only in old age. Of the 6 trait categories, 4 demonstrated significant change in middle and old age. Gender and attrition had minimal effects on change, whereas longer studies and studies based on younger cohorts showed greater change.

Policy-makers are considering large-scale programs aimed at self-control to improve citizens’ health and wealth and reduce crime. Experimental and economic studies suggest such programs could reap benefits. Yet, is self-control important for the health, wealth, and public safety of the population? Following a cohort of 1,000 children from birth to the age of 32 y, we show that childhood self-control predicts physical health, substance dependence, personal finances, and criminal offending outcomes, following a gradient of self-control. Effects of children's self-control could be disentangled from their intelligence and social class as well as from mistakes they made as adolescents. In another cohort of 500 sibling-pairs, the sibling with lower self-control had poorer outcomes, despite shared family background. Interventions addressing self-control might reduce a panoply of societal costs, save taxpayers money, and promote prosperity.

The present study used meta-analytic techniques to test whether trait consistency maximizes and stabilizes at a specific period in the life course. From 152 longitudinal studies, 3,217 test-retest correlation coefficients were compiled. Meta-analytic estimates of mean population test-retest correlation coefficients showed that trait consistency increased from .31 in childhood to .54 during the college years, to .64 at age 30, and then reached a plateau around .74 between ages 50 and 70 when time interval was held constant at 6.7 years. Analysis of moderators of consistency showed that the longitudinal time interval had a negative relation to trait consistency and that temperament dimensions were less consistent than adult personality traits.

In this review, we evaluate four topics in the study of personality development where discernible progress has been made since 1995 (the last time the area of personality development was reviewed in this series). We (a) evaluate research about the structure of personality in childhood and in adulthood, with special attention to possible developmental changes in the lower-order components of broad traits; (b) summarize new directions in behavioral genetic studies of personality; (c) synthesize evidence from longitudinal studies to pinpoint where and when in the life course personality change is most likely to occur; and (d) document which personality traits influence social relationships, status attainment, and health, and the mechanisms by which these personality effects come about. In each of these four areas, we note gaps and identify priorities for further research.

The ability of personality traits to predict important life outcomes has traditionally been questioned because of the putative small effects of personality. In this article, we compare the predictive validity of personality traits with that of socioeconomic status (SES) and cognitive ability to test the relative contribution of personality traits to predictions of three critical outcomes: mortality, divorce, and occupational attainment. Only evidence from prospective longitudinal studies was considered. In addition, an attempt was made to limit the review to studies that controlled for important background factors. Results showed that the magnitude of the effects of personality traits on mortality, divorce, and occupational attainment was indistinguishable from the effects of SES and cognitive ability on these outcomes. These results demonstrate the influence of personality traits on important life outcomes, highlight the need to more routinely incorporate measures of personality into quality of life surveys, and encourage further research about the developmental origins of personality traits and the processes by which these traits influence diverse life outcomes.Starting in the 1980s, personality psychology began a profound renaissance and has now become an extraordinarily diverse and intellectually stimulating field (Pervin & John, 1999). However, just because a field of inquiry is vibrant does not mean it is practical or usefulone would need to show that personality traits predict important life outcomes, such as health and longevity, marital success, and educational and occupational attainment. In fact, two recent reviews have shown that different personality traits are associated with outcomes in each of these domains (Caspi, Roberts, & Shiner, 2005;Ozer & Benet-Martinez, 2006). But simply showing that personality traits are related to health, love, and attainment is not a Address correspondence to Brent W. Roberts, Department of Psychology, University of Illinois at Urbana-Champaign, 603 East Daniel Street, Champaign, IL 61820; broberts@cyrus.psych.uiuc.edu. HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript stringent test of the utility of personality traits. These associations could be the result of "third" variables, such as socioeconomic status (SES), that account for the patterns but have not been controlled for in the studies reviewed. In addition, many of the studies reviewed were cross-sectional and therefore lacked the methodological rigor to show the predictive validity of personality traits. A more stringent test of the importance of personality traits can be found in prospective longitudinal studies that show the incremental validity of personality traits over and above other factors.The analyses reported in this article test whether personality traits are important, practical predictors of significant life outcomes. We focus on three domains: longevity/mortality, divorce, and occupational attainment in work. Within each domain, we evaluate empirica...

Previous research has established conscientiousness as a predictor of longevity (H. S. Friedman et al., 1993; L. R. Martin & H. S. Friedman, 2000). To better understand this relationship, the authors conducted a meta-analysis of conscientiousness-related traits and the leading behavioral contributors to mortality in the United States (tobacco use, diet and activity patterns, excessive alcohol use, violence, risky sexual behavior, risky driving, suicide, and drug use). Data sources were located by combining conscientiousness-related terms and relevant health-related behavior terms in database searches as well as by retrieving dissertations and requesting unpublished data from electronic mailing lists. The resulting database contained 194 studies that were quantitatively synthesized. Results showed that conscientiousness-related traits were negatively related to all risky health-related behaviors and positively related to all beneficial health-related behaviors. This study demonstrates the importance of conscientiousness' contribution to the health process through its relationship to health-related behaviors.

Recent longitudinal and cross-sectional aging research has shown that personality traits continue to change in adulthood. In this article, we review the evidence for mean-level change in personality traits, as well as for individual differences in change across the life span. In terms of mean-level change, people show increased selfconfidence, warmth, self-control, and emotional stability with age. These changes predominate in young adulthood (age 20-40). Moreover, meanlevel change in personality traits occurs in middle and old age, showing that personality traits can change at any age. In terms of individual differences in personality change, people demonstrate unique patterns of development at all stages of the life course, and these patterns appear to be the result of specific life experiences that pertain to a person's stage of life.Keywords personality development; personality traits; mean-level change; individual differences in change Personality traits are defined as the relatively enduring patterns of thoughts, feelings, and behaviors that distinguish individuals from one another. Whether personality traits continue to develop in adulthood depends in part on how one defines "relatively enduring." In the past, some researchers took that phrase to mean-and the empirical literature to indicatethat personality traits stopped changing in adulthood (McCrae & Costa, 1994). Since 1994, cross-sectional and longitudinal studies of personality-trait change in adulthood have forced a reevaluation of the assumption that personality traits do not change in adulthood (e.g., Mroczek & Spiro, 2003;Roberts, Walton, & Viechtbauer, 2006;Srivastava, John, Gosling, & Potter, 2003). Research now shows that personality traits continue to change in adulthood and often into old age, and that these changes may be quite substantial and consequential. In this article, we provide an overview of the evidence for personality-trait change in adulthood and outline some of the possible reasons for these changes. Before we discuss these findings further, we describe what we mean by change. DEFINITIONS OF PERSONALITY CONTINUITY AND CHANGEResearchers often fail to clarify what they mean when they describe personality as consistent or changeable. Part of the difficulty arises from the multiple indices for tracking continuity and change-such as mean-level change, rank-order consistency (relative ordering of people over time), structural consistency (e.g., similar factor structures over time), and individual differences in change. A complete understanding of personality continuity and change can only come from a thorough examination of multiple indices, as they are often independent of

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