Genetic and environmental effects on political preferences and party identification in adolescence and early adulthood: An Extended Twin Family Analysis

Political preferences and party identification have been subject of extensive research. Both aspects have been seen as mainly socially influenced attitudes for a long time. However, recent analyses have also found substantial... [ view full abstract ]

Political preferences and party identification have been subject of extensive research. Both aspects have been seen as mainly socially influenced attitudes for a long time. However, recent analyses have also found substantial genetic influence on social attitudes and political traits, but still little is known about the concrete pathways through which genes and environment exert influence.

Since the Classical Twin Design has several limitations, we implemented a Nuclear Twin Family Design in a study of 4097 (same-sex MZ and DZ) twins reared together, their biological parents and full siblings. The twins were 17 and 23 years old, an age which marks an important transition from adolescence to young adulthood where most people start to engage in social or political activities. This design enables us to detect additive and non-additive genetic effects simultaneously and to account for assortative mating, cultural transmission and passive gene-environment correlations as well as a twin-specific (possibly age-related) environment. We asked the participants how close they felt to the currently most successful eight German parties and arranged the parties on a left-right continuum.

We found substantial additive genetic effects that increase with age while shared environmental influences are small and tend to decrease. Interestingly, direct non-genetic parental effects were significant. Concerning the twin specific environment we obtained mixed results. In addition, variables that could act as potential moderators such as sex, socioeconomic status and personality were investigated. We discuss the findings with regard to their contributions to disentangle the intertwined mechanisms that influence political attitudes.