Authoritarianism revisited: genetic and environmental influences examined in twins reared apart and together

Historically, authoritarian attitudes have been attributed to influences within the rearing environment, based on the incorrect assumption that similarity between family members demonstrates cultural transmission. To unconfound environmental and genetic influences, this paper examines right-wing authoritarianism [RWA; Altemeyer, B. (1981). Right-wing authoritarianism. Winnipeg: University of Ottowa; Altemeyer, B. (1988). Enemies of freedom. San Francisco: Jossey-Bass Publishers] employing data from 39 monozygotic and 38 dizygotic adult reared apart twin pairs and 423 monozygotic and 434 dizygotic adult reared together twin pairs. Genetic factors accounted for about 50% and unshared environment for 35% of the phenotypic variance; either common environment or assortative mating could explain the remaining reliable variance. Similarity in cognitive ability did not underlie the twin correlations on authoritarianism. Purportedly relevant environmental variables from the Moos and Moos Family Environmental Scale (FES), the Block Environment Questionnaire (BEQ) and the MISTRA life history were associated with RWA scores for individuals reared by biological relatives; among adoptees, however, these variables are unrelated to RWA scores.