The general factor of personality: Questions and elaborations

Predictions from Rushton’s theory that a general factor of personality (GFP) has evolved based on effective social participation were examined in two large samples of adult Australian twins (5834 and 3672 individuals) and their relatives (8303 and 2677). General factors based on items and scales were compared to each other, across two different questionnaires, and between adults and adolescents. Behavior-genetic analyses based on the twin samples tested predictions comparing GFPs to scales with the GFP partialled out. Some support was found for Rushton’s theory, but the GFP was only marginally more heritable than the GFP-free scales and was not especially marked by the expected non-additivity of its genetic variance; moreover, the adult and adolescent GFPs showed substantial differences.