Preferring domination or egalitarianism: Genetic and environmental structure of Social Dominance Orientation

PURPOSE: Social Dominance Orientation (SDO) is a measure that describes individual differences in the preference for some groups to dominate over others. SDO is a robust predictor of sociopolitical attitudes and behaviors,... [ view full abstract ]

PURPOSE: Social Dominance Orientation (SDO) is a measure that describes individual differences in the preference for some groups to dominate over others. SDO is a robust predictor of sociopolitical attitudes and behaviors, including racism and extreme intergroup violence. Initially, SDO was considered a unitary construct, but more recently it has been argued that the construct consists of two subcomponents: Dominance (SDO-D) and Egalitarianism (SDO-E). Dominance is the desire for some groups to be actively oppressed (e.g. old-fashioned racism), while SDO-E is a preference for inequality without any support for overt oppression of groups. This paper seeks to understand the genetic and environmental structure of Dominance and Egalitarianism. METHODS: Our sample consists of male monozygotic (N=239), female monozygotic (N=304), and male dizygotic (N=324) and female dizygotic (N=412) twins. We measured SDO with a Norwegian translation of SDO-6. Model parameters were estimated with full information maximum likelihood using the R package OpenMx. Results: An AE model without sex limitation was found to have overall best fit compared to seven other models, as evaluated by lowest AIC (3518.6). The estimated heritabilities for Dominance and Egalitarianism were found to be 0.36 and 0.24 respectively, while the genetic correlation between the SDO subdomains was estimated to 0.5 (CI: 0.294 - 0.686). Conversely, the unique environmental correlation was found to be 0.38 (CI: 0.297 – 0.456).
CONCLUSION: SDO-Dominance and SDO-Egalitarianism modestly overlap at the underlying genetic and environmental architecture. Our results suggest no evidence for shared environmental effects, nor any quantitative sex differences.