Inducing Motivated Reasoning: Confirmation Bias and Attitude Polarization Among Liberals and Conservatives

What types of motives trigger politically motivated reasoning? In two large-scale experiments (total N = 5,403) involving four contentious political issues, we investigated two psychological mechanisms that could trigger biased reasoning and attitude polarization: (1) epistemic motives to reduce uncertainty, manipulated by raising uncertainty about politically relevant evidence; and (2) relational motives to establish within-group homogeneity, manipulated through social cueing. We also investigated ideological symmetries and asymmetries in these processes. In the presence of uncertainty cues, results revealed that liberals moderated their attitudes, whereas conservatives maintained pre-existing opinions. Social cues, on the other hand, increased attitude polarization in liberals and conservatives alike. These findings highlight psychological similarities and dissimilarities between liberals and conservatives and show that multiple motives, when temporarily activated, are capable of contributing to biased reasoning.