Friendships Moderate an Association Between a Dopamine Gene Variant and Political Ideology

Abstract

Scholars in many fields have long noted the importance of social context in the development of political ideology. Recent work suggests that political ideology also has a heritable component, but no specific gene variant associated with political ideology has so far been identified. In this article we hypothesize that individuals with a genetic predisposition towards seeking out new experiences will tend to be more liberal, but only if they are embedded in a social context that provides them with multiple points of view. Using data from the National Longitudinal Study of Adolescent Health, we test this hypothesis by investigating an association between self-reported political ideology and the 7R variant of the dopamine receptor D4 gene (DRD4), which has previously been associated with novelty-seeking. We find that the number of friendships a person has in adolescence is significantly associated with liberal political ideology among those with DRD4-7R. Among those without the gene variant there is no association. This is the first study ever to elaborate a specific gene-environment interaction that contributes to ideological self-identification, and it highlights the importance of incorporating both nature and nurture into the study of politics.