1. Personality Development Two questions of personality development How do we come to have the personalities we do? 1. Personality class provided various theoretical perspectives 2. Genes and gene-environment transactions What happens to personality across development? Change Stability Person-environment transactions

2. How do we come to have the personalities that we do? Long thought to be due to parenting and family influences Long thought to be due to parenting and family influences Examples: Examples: parents that read to their children parents that read to their children Parents that are violent and aggressive in punishments have children that are aggressive Parents that are violent and aggressive in punishments have children that are aggressiveEtc.

3. Role of parenting Most effects are correlational Most effects are correlational Fail to recognize that parents also share same genes as children Fail to recognize that parents also share same genes as children Twin studies have addressed this problem Twin studies have addressed this problem

4. Twin Studies MZ twins and DZ twins Suggests heritability estimates of.5 for personality traits Shared environment = what siblings share, parenting practices, neighborhood, family life Nonshared environment is everything else. More important than shared environment

5. Importance of nonshared environment 1. Adult siblings’ personalities are about equally correlated whether they grew up together or apart. 2. Adoptive siblings are no more similar than two random people from same culture 3. MZ twins are no more similar than effect of shared genes Differences may be due to random events that people experience Differences may be due to random events that people experience

6. What happens to personality across development? Are traits stable as we develop or do they change? Is an issue of stability Several ways that stability can be studied

7. Types of Stability 1. 1. Intraindividual differences in consistency – how each individual changes with time 2. 2. Ipsative differences – how the salience of attributes changes within individuals over time e.g. Block (1971) found a group of men for whom talkativeness and rebelliousness become more important as they moved from teen-age years to young adulthood 3. 3. Mean-level consistency (population level) – looks at whether groups of people increase or decrease on trait dimensions over time E.g. conscientiousness goes up in adulthood 4. 4. Rank-order consistency (population level) – relative placement of individuals within a group. Do groups of people retain the same rank ordering on trait dimensions over time? People get taller with age but percentile rank may remain stable

8. Levels of analysis 1. Population level – those that apply to everyone Sexual interest increases at puberty for almost everyone Sexual interest increases at puberty for almost everyone Impulsiveness decreases with age Impulsiveness decreases with age 2. Group differences level – changes over time that affect groups differently Male teen-agers are higher risk takers than females Male teen-agers are higher risk takers than females White women more at risk for eating disorders White women more at risk for eating disorders 3. Individual differences level – which individuals change over time? Who will be at risk for particular outcomes, etc.

9. Rank-Order Stability of Personality Roberts, B. & DelVecchio, W. (2000). The rank- order consistency of personality traits from Childhood to old age: A quantitative review of longitudinal studies. Psychological Bulletin, 126, 3-25. Meta-analysis (combines multiple studies) 152 longitudinal studies 3,217 test-retest correlations Organized according to Big Five

10. Rank order stability study Interested in whether people retain the same rank ordering on traits over time Interested in whether people retain the same rank ordering on traits over time Other types of change may also occur, but each methodological approach addresses a different question Other types of change may also occur, but each methodological approach addresses a different question

11. Relative Stability of Personality

12. Meaning of previous Trait consistency steadily increases with age Trait consistency steadily increases with age Consistency peaked at 50-59 age Consistency peaked at 50-59 age Lowest at ages 0 to 3 Lowest at ages 0 to 3

13. Relative Stability of Personality

16. Analysis of previous data Adult personality traits are more consistent than childhood temperament traits Adult personality traits are more consistent than childhood temperament traits Agreeableness & extraversion were most consistent (but other Big Five traits also consistent) Agreeableness & extraversion were most consistent (but other Big Five traits also consistent) Some change DOES occur in adulthood (in contrast to Costa & McCrae) Some change DOES occur in adulthood (in contrast to Costa & McCrae)

17. Relative Stability of Personality Important conclusions: Trait consistency increases with age 0.31 in childhood 0.54 in college years 0.64 at age 30 Plateaus between 50 and 70 at.74 The longer the interval the lower the stability Personality more stable than temperament No differences among Big 5

18. Costa & McCrae Personality is “set like plaster” by age 30 Personality is “set like plaster” by age 30 Some debate about this (ages 50 to 70 appear to be more stable) Some debate about this (ages 50 to 70 appear to be more stable) Certainly the 20s is an important time to look at for personality development Certainly the 20s is an important time to look at for personality development People often gaining independence from families People often gaining independence from families Moving away Moving away Going to college and/or joining workforce Going to college and/or joining workforce Getting into committed relationships and having children Getting into committed relationships and having children

19. Example: Stability in Children McCrae, R.R., Costa, P.T., Terracciano, A., Parker, W.D., Mills, C.J., de Fruyt, P., & Mervielde, I. (2002). Personality trait development from age 12 to age 18: Longitudinal, cross-sectional, and cross-cultural analyses. Journal of Personality and Social Psychology, 83, 1456-1468. Longitudinal study of intellectually gifted students 4 years: 12 to 16 N = 230 NEO-PI-R

20. Example: Stability in Children

24. Example: Stability in College Students Robins, R.W., Fraley, R.C., Roberts, B.W., & Trzesniewski, K.H. (2001). A longitudinal study of personality change in young adulthood. Journal of Personality, 69, 617- 640. Longitudinal study of college students N = 270 Assessed when first entered college and 4 years later FFI

25. Example: Stability in College Students

27. Mean-level Consistency of Personality Srivastava, S., John, O.P., Gosling, S.D., & Potter, J. (2003). Development of personality in early and middle adulthood: Set like plaster or persistent change? Journal of Personality and Social Psychology, 84, 1041-1053 Internet study N = 132,515 Aged 21 to 60 (cross-sectional) Completed BFI on-line Aimed at countering C & M—no changes after 30

28. Mean-level Stability of Personality

31. Summarize

32. Mechanisms of Continuity Environmental stability Three types of person-environment transactions Reactive Different individuals exposed to the same environment, experience it, interpret it, and react to it differently Example: schemas Evocative An individual's personality evokes distinctive responses form others Examples: coercive child, happy child Proactive/Selective Individuals select or create environments of their own