Sources of Differences in Right-Wing Authoritarianism and Social Dominance Orientation from Adolescence to Adulthood: A Multi-Cohort Twin Family Study.

Past research indicates that genetic and environmental sources contribute to Right-Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO). However, less is known about the differences between the sources of variance in RWA and SDO, and how these sources differ across different developmental stages. Based on data from 1440 twin families, including 1198 complete twin pairs, 435 non-twin full siblings, and 2016 parents of twins from the German TwinLife project, nuclear twin family modeling was used to estimate different genetic and environmental variance components of RWA and SDO, and to examine the extent to which the variance components vary across three age cohorts of twins (average age 15, 21, and 27 years). We hypothesized increasing levels of genetic variance across age cohorts, reflecting more active genotype-environment transactions with development, and declining levels of passive genotype-environment correlation (rGE). The model analyses yielded additive and nonadditive genetic factors as well as influences shared in families due to non-genetic intergenerational transmission from parents to offspring and significant passive rGE for RWA. For SDO, passive rGE components, nonadditive genetic components and non-genetic intergenerational transmission were negligible. However, significant individual environmental sources and those only shared by twins were found for both RWA and SDO. Inconsistent with our expectations, passive rGE and genetic variance did not vary significantly across age cohorts. Counterintuitively, the influence of twin-specific shared environmental factors on RWA was larger in adulthood than adolescence, suggesting increasingly relevant environmental influences across developmental periods. These results have important implications for socio-developmental theories on socio-political attitudes.