Nuclear Twin Family analysis: Political orientation is often assumed to be shaped by socialization processes, but previous studies have shown substantial genetic variance components in party affiliation, political attitudes & behaviors

Hufer, A., Kornadt, A. E., Kandler, C., & Riemann, R. (2019). Genetic and environmental variation in political orientation in adolescence and early adulthood: A Nuclear Twin Family analysis. Journal of Personality and Social Psychology, http://dx.doi.org/10.1037/pspp0000258

Abstract: Political orientation is often assumed to be shaped by socialization processes; however, previous studies have shown substantial genetic variance components in party affiliation, political attitudes and behaviors, or closely related personality traits. The majority of these studies have relied on the Classical Twin Design, which comes with restrictive assumptions, some of which are easily violated. Moreover, most analyses lack a perspective of age-group differences. In this study, we investigated political orientation in adolescents (age: 16–18) and young adults (age: 21–25) in a cross-sectional Nuclear Twin Family Design. We used data of the German TwinLife project, including data from same-sex twins reared together, their biological parents, and nontwin full siblings. We found genetic variation in political orientation, which was significant in the older cohort, possibly indicating an increasing importance of active gene-environment correlation from adolescence to adulthood. Individual differences in political orientation because of passive gene-environment correlation and shared environmental effects were larger in the younger cohort, substantiating the same theoretical consideration and the importance of shared socialization contexts for adolescents’ political views. By running Nuclear Twin Family model analyses, and considering age-group differences, as well as the relationship of political orientation with the Big Five personality traits, our study extended previous work, and resulted in more robust and fine-grained estimates of genetic and environmental sources of variance in political orientation. Therefore, it contributed to a better understanding of the complex nature–nurture interplay that forms political orientation in emerging adulthood.