Group value learned through interactions with members: A reinforcement learning account

How do group-based interaction tendencies form through encounters with individual group members? In three experiments, in which participants interacted with group members in a reinforcement learning task presented as a money sharing game, participants formed instrumental reward associations with individual group members through direct interaction and feedback. Results revealed that individual-level reward learning generalized to a group-based representation, as indicated in self-reported group attitudes, trait impressions, and the tendency to choose subsequent interactions with novel members of the group. Moreover, group-based reward values continued to predict interactions with novel members after controlling for explicit attitudes and impressions, suggesting that instrumental learning contributes to an implicit form of group-based choice. Experiment 3 further demonstrated that group-based reward effects on interaction choices persisted even when group reward value was no longer predicted of positive outcomes, consistent with a habit-like expression of group bias. These results demonstrate a novel process of prejudice formation based on instrumental reward learning from direct interactions with individual group members. We discuss implications for existing theories of prejudice, the role of habit in intergroup bias, and intervention strategies to reduce prejudice.