HERITABILITY OF THE BIG-5 PERSONALITY DIMENSIONS AND THEIR FACETS - ATWIN STUDY

The genetic and environmental etiology of the five-factor model of per sonality as measured by the revised NEO Personality Inventory (NEO-PI- R) was assessed using 123 pairs of identical twins and 127 pairs of fr aternal twins. Broad genetic influence on the five dimensions of Neuro ticism, Extraversion, Openness, Agreeableness, and Conscientiousness w as estimated at 41%, 53%, 61%, 41%, and 44%, respectively. The facet s cales also showed substantial heritability, although for several facet s the genetic influence was largely nonadditive. The influence of the environment was consistent across all dimensions and facets. Shared en vironmental influences accounted for a negligible proportion of the va riance in most scales, whereas nonshared environmental influences acco unted for the majority of the environmental variance in all scales.