Choosing sides. The genetics of why we go with the loudest

Recent developments in spatial voting have moved beyond finding the most appropriate utility function and started to assess individual differences in decision strategy. The question is not if a proximity or directional worldview performs better in general, rather under what conditions do people pick one strategy over the other? We draw on psychological theories to develop a survey-based measure of individual decision strategy and take a behavior genetic route to explaining the individual differences. We argue that dispositional traits shape whether an individual develops a directional or proximity worldview of the political arena. Utilizing a classical twin design, we capitalize on the documented relationship between partisanship and a directionalist worldview. We find that, in the Minnesota Twin Political Survey, both the strength of party identification and directional voting are moderately (~20 percent) but significantly (p < 0.05) heritable with no socialized component contributing to the variance. The covariation between the two traits is predominantly driven by common underlying genetic effects (p < 0.01). Implications for the rational voter models are discussed in light of the findings.