Partisan Bias in Political Judgment

Abstract

This article reviews empirical data demonstrating robust ingroup favoritism in political judgment. Partisans display systematic tendencies to seek out, believe, and remember information that supports their political beliefs and affinities. However, the psychological drivers of partisan favoritism have been vigorously debated, as has its consistency with rational inference. We characterize decades-long debates over whether such tendencies violate normative standards of rationality, focusing on the phenomenon of motivated reasoning. In light of evidence that both motivational and cognitive factors contribute to partisan bias, we advocate for a descriptive approach to partisan bias research. Rather than adjudicating the (ir)rationality of partisan favoritism, future research should prioritize the identification and measurement of its predictors and clarify the cognitive mechanisms underlying motivated political reasoning. Ultimately, we argue that political judgment is best evaluated by a standard of ecological rationality based on its practical implications for individual well-being and functional democratic governance.