GENETIC AND ENVIRONMENTAL-EFFECTS ON OPENNESS TO EXPERIENCE, AGREEABLENESS, AND CONSCIENTIOUSNESS - AN ADOPTION TWIN STUDY

Previous research has indicated that extraversion and neuroticism are substantially affected both by genotype and environment. This study as sesses genetic and environmental influences on the other three compone nts of the five-factor model of personality: Openness to Experience, A greeableness, and Conscientiousness. An abbreviated version of the NEO Personality Inventory (NEO-PI) was administered to 82 pairs of identi cal twins and 171 pairs of fraternal twins reared apart and 132 pairs of identical twins and 167 pairs of fraternal twins reared together. E stimates of genetic and environmental effects for Openness and Conscie ntiousness were similar to those found in other studies of personality : Genetic influence was substantial and there was little evidence of s hared rearing environment. Results for Agreeableness were different: G enetic influence accounted for only 12% of the variance and shared rea ring environment accounted for 21% of the variance. Few significant ge nder or age differences for genetic and environmental parameters were found in model-fitting analyses.