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.