Development of big five domains and facets in adulthood: mean-level age trends and broadly versus narrowly acting mechanisms.

Data from a cross-sectional sample (N = 601 men and women) and a longitudinal sample (N = 125 women) were used to test hypotheses about the development of Big Five domains and facets from early adulthood through middle age. Analyses of mean-level age trends indicated that overall Agreeableness and Conscientiousness increased with age and that several facets showed distinctive trends that replicated across the samples. Cross-sectional analyses of trait intercorrelations and covariances indicated that interrelations between the Big Five domains, and between their more specific facets, were quite similar at older versus younger ages. Finally, longitudinal analyses of individual-level changes indicated that (a) different people's personalities changed in markedly different ways; (b) these changes were predominantly independent, rather than correlated, across Big Five domains; and (c) the pattern of change correlations between Big Five facets could be explained by the facets' interrelations at the first assessment time. Taken together, these results suggest that a complete understanding of personality development requires consideration of facet-level traits and that adult personality development is predominantly influenced by narrowly acting mechanisms that each affect a single Big Five domain, or a small cluster of related facets, rather than by broadly acting mechanisms that simultaneously affect previously independent traits.