In this article, we examine whether there is genetic overlap between personality traits and political participation, interest, and efficacy. We make several contributions to the literature. First, we use new data from a large sample of twins from Denmark to examine the link between genes, the Big Five traits, and political behavior. Previous research in this area has not examined the Danish context. Second, because our measures have some overlap with those used in previous studies, we are able to examine whether previous findings replicate in a different sample. Finally, we extend the literature by examining the possible genetic link between some personality and political traits that have not yet been explored. Overall, we find that genes account for a fairly large share of the correlation between two of the Big Five personality traits (openness and extraversion), political participation, and political interest. Thus, most of the relationship between these personality traits and our measures of political behavior can be accounted for by a common underlying genetic component.

Twin studies have revealed political ideology to be partially heritable. Neurological research has shown that ideological differences are reflected in brain structure and response, suggesting a direct genotype-phenotype link. Social and informational environments, however, also demonstrably affect brain structure and response. This leads to a “chicken-and-egg” question: do genes produce brains with ideological predispositions, causing the preferential absorption of consonant information and thereby forming an ideology, or do social and informational environments do most of the heavy lifting, with genetic evidence the spurious artifact of outdated methodology? Or are both inextricably intertwined contributors? This article investigates the relative contributions of genetic and environmental factors to ideological development using a role-play experiment investigating the development of opinions on a novel political issue. The results support the view that the process is bidirectional, suggesting that, like most traits, political ideology is produced by the complex interplay of genetic and (social/informational) environmental influences.