Basic Research In Personality

Aging

Investigators

Linked publications & trials

Abstract

Personality stability and change in the GZTS and NEO-PI-R[unreadable] [unreadable] In the two preceding years, we have examined longitudinal trajectories of personality traits using the NEO-PI-R (over a 15 year period) and the Guilford-Zimmerman Temperament Survey (GZTS; over a period as long as 42 years). This research has helped clarify how personality changes over the life course. What remains a hotly debated question, however, is at what age personality reaches its greatest rank-order stability and whether this stability is seen over the remainder of the life course. [unreadable] Two recent meta-analyses found that rank-order consistency: (1) Increased with age, even in adulthood, where those older than 50 years are most stable; (2) Increased up to age 50, then decreased thereafter. This is in contrast to other research (McCrae & Costa, 1990), which has concluded that personality change is the exception rather than the rule after age 30. To address this issue, we examined rank-order consistencies within the Baltimore Longitudinal Study on Aging (BLSA) for both the NEO-PI-R and GZTS. Results demonstrated that for 4 GZTS scales, in particular Ascendance or Assertiveness, rank-order consistency increased between the ages of 30 and 50, supporting the conclusion that rank-order stability increases to age 50. However, for the remaining GZTS scales and all NEO-PI-R factors, there was no such increase in consistency, supporting the perspective that rank-order consistency in personality remains largely the same after age 30.[unreadable] These age trajectories are also consistent with many cross-cultural results in the study of personality. In a recently published chapter, we reviewed the contribution of cross-cultural studies to understanding how personality changes with age. The main conclusions from this review were: (1) The pattern of age differences is remarkably similar across vastly different cultures; (2) It seems increasingly likely that the effects are maturational rather than generational; and (3) Cross-cultural research seems to point to intrinsic, species-wide, and thus biologically based causes for age changes.[unreadable] [unreadable] Replicability of personality types[unreadable] [unreadable] Claims for discrete personality types, characterized by a distinctive profile of personality traits, has appeared repeatedly in the history of personality psychology. However, their empirical status is questionable. To address the replicability of personality types, we examined 1540 responses to the California Adult Q-sort (CAQ) for members of the BLSA. Conventional factor analysis of the items showed the expected Five-Factor Model (FFM). Inverse factor analysis across random subsamples showed that none of the previously reported person-factors were replicated. Only two factors were replicable, and, most importantly, these factors were contaminated by mean level differences in item endorsement. Results were not due to sample size or age heterogeneity. Subsequent inverse factor analysis of standardized items revealed at least three replicable factors; when five person-factors were extracted, they could be aligned precisely with the dimensions of the FFM. The major factors of person similarity can be accounted for entirely in terms of the FFM, consistent with the hypothesis that there are no replicable personality types in the CAQ. These results support the notion of closing the door on personality types.[unreadable] [unreadable] Genetic Architecture of Personality[unreadable] [unreadable] The Five-Factor Theory (FFT) posits the personality traits of the FFM as biologically-based basic tendencies. To explore this biological basis, we examined the heritability of NEO-PI-R domain and facet traits in a sample of 6,148 Sardinians. Across all 35 domains and facets, genetic effects explained 19% of the variance, ranging from 9.4% for the Agreeableness facet Tender-Mindedness to 32.8% for Openness to Experience. This demonstrates clearly a genetic, biological component to the FFM dimensions. [unreadable] [unreadable] Moreover, we examined the genetic correlation coefficients between personality traits to better understand the genetic factor structure of the personality traits. In order to assess the similarity of this genetic factor structure to the American normative phenotypic structure, we rotated the obtained genetic structure toward normative structure and obtained factor and facet congruence coefficients. All factors had high congruence coefficients with the American normative structure (>.85), indicating that the genetic structure replicates the phenotypic structure well. This analysis suggests that the phenotypic covariation of personality traits is genetically rooted, or in other words, that shared genes underlie the facets that define each factor.[unreadable] [unreadable] Taken together, the genetic structure work points to a biological basis for age-related changes in personality, and the heritability estimates confirm this. The replicated genetic factor structure is even more striking: We can now see that the phenotypic covariation of traits is replicated at the genotypic level, giving personality clear genetic roots.Work continues presently on identifying possible founder effects of the personality traits, and genomic regions associated with the NEO-PI-R domains and facets.