A genetic basis for social trust?

A propensity to believe that fellow citizens will not act against our interests in social and economic transactions has been identified as key to the effective functioning of democratic polities. Yet the causes of this type of 'generalized' or 'social' trust are far from clear. To date, researchers within the social and political sciences have focused almost exclusively on social-developmental and political/institutional features of individuals and societies as the primary causal influences. In this paper we investigate the intriguing possibility that social trust might have a genetic, as well as an environmental basis. We use data collected from samples of monozygotic and dizygotic twins to estimate the additive genetic, shared environmental, and non-shared environmental components of trust. Our results show that the majority of the variance in a multi-item trust scale is accounted for by an additive genetic factor. On the other hand, the environmental influences experienced in common by sibling pairs have no discernable effect; the only environmental influences appear to be those that are unique to the individual. Our findings problematise the widely held view that the development of social trust occurs through a process of familial socialization at an early stage of the life course.