Novel Social Identities Shape Belief in True and False Information

Classic social psychological accounts of belief formation propose that beliefs can be influenced by directional motives to reach specific conclusions. Such theories have been particularly influential in recent accounts of the spread of political misinformation. However, the assumption of directionally-motivated belief formation has been challenged by theories reexplaining motivational effects in terms of purely cognitive factors like prior beliefs or information exposure. The goal of the present manuscript is to provide a direct test of the assumption that social-identity-based motives can shape what people believe. We report three experiments (N = 1,459) causally isolating the effects of identity-based directional motives on belief formation using minimal groups. In Experiment 1, participants were more likely to trust, and thus believe statements endorsed by, arbitrarily assigned in-group versus out-group members. Experiment 2 replicates these findings and experimentally demonstrates that this in- group bias in belief can be affected by social motivations to affiliate with groups: exposing participants to social exclusion selectively reduced belief in statements endorsed by out-group members. Experiment 3 suggests that these effects arise because social motivations moderate people's relative trust in novel in-group over out-group members. Together, these results address longstanding debates about the possible role of social motivations in epistemic processes by demonstrating that social identities, unconfounded from other explanatory factors, can shape who people trust and what they believe.