Exploring the Phenotypic Structure and Etiology of the Big 5 Personality Dimensions in Youth

Numerous researchers have examined the phenotypic structure of (McCrae et al., 1996) and genetic and environmental influences on (Loehlin, McCrae, Costa, & John, 1998) adult personality, but little research has examined these... [ view full abstract ]

Numerous researchers have examined the phenotypic structure of (McCrae et al., 1996) and genetic and environmental influences on (Loehlin, McCrae, Costa, & John, 1998) adult personality, but little research has examined these issues in youth. The present study used a representative twin sample (N=507) aged 6 to 16 (51% female) to examine two specific aims. First, we tested alternative competing models for the phenotypic structure of youth personality using confirmatory factor analytic (CFA) and exploratory structural equation (ESEM) models. Second, we fit alternative biometric models to elucidate the etiology of the personality dimensions derived from the best-fitting phenotypic model. Consistent with our hypotheses, the factor analyses broadly supported the five-factor model in youth. Nevertheless, a strict five-factor CFA model did not fit as well as the five-factor ESEM model (Marsh et al., 2010). Full measurement and structural invariance across zygosity was met for the best-fitting ESEM model, suggesting that this factor structure replicated across MZ and DZ twins. All big five dimensions were substantially heritable, with estimates ranging from 42% (Neuroticism) to 77% (Openness to Experience). There also were moderate nonshared environmental influences, with estimates ranging from 58% (Neuroticism) to 23% (Openness to Experience), but no evidence for shared environmental influences. Significant rater contrasts were found for Extraversion and Openness to Experience, which is broadly consistent with rater contrasts detected in the ADHD literature (Freitag, Rohde, Lempp, & Romanos, 2010), given the relevance of these traits (e.g., activity, cognitive flexibility) for ADHD (Martel et al., 2011). Taken together, our findings replicate and extend personality research on adults by suggesting that the big five domains can be reliably and validly assessed in youth, and that these dimensions are substantially heritable.