The origins of party identification and its relationship to political orientations

• The data indicate that political party identification (PID) is partially heritable.
• Political orientations and PID have much genetic variance in common.
• Political orientations may mediate the effect of genetic influences on PID.

An established position, long recognized in the literature, maintains that political party identification (PID) arises mainly from familial socialization and has a major impact on political outlooks and behaviors. An alternative view, also entrenched in the literature, holds that the direction of causation may go the other way, with political orientations influencing PID insofar as individuals seek out parties that match their ideological viewpoints. Here we use univariate and multivariate twin modeling to examine the underlying etiology assumed by those two positions, and introduce a new perspective that may help researchers make sense of PID, political orientations, and the relationships between them. Our findings indicate that: (1) PID is substantially heritable; and (2) there is empirical support for a model in which genetic and environmental factors influence political orientations, which in turn affect PID.