HERITABILITIES OF COMMON AND MEASURE-SPECIFIC COMPONENTS OF THE BIG 5PERSONALITY-FACTORS

Three different measures of the Big Five personality dimensions were d eveloped from the battery of questionnaires used in the National Merit Twin Study: one from trait self-rating scales, one from personality i nventory items, and one from an adjective check list. Behavior-genetic models were fit to what the three measures had in common, and to the variance distinctive to each. The results of the model fitting agreed with other recent studies in showing the Big Five dimensions to be sub stantially and about equally heritable, with little or no contribution of shared family environment. Heritabilities for males and females di d not differ significantly. For Agreeableness and Conscientiousness, s ome effect of shared environment was found for measure-specific varian ce on the personality inventory, and for Extraversion and Neuroticism, models involving nonadditive genetic variance or twin contrast effect s provided slightly better fits. (C) 1998 Academic Press.