Race Effects on Impression Formation in Social Interaction: An Instrumental Learning Account

How does race influence the impressions we form through direct interaction? In two preregistered experiments (N = 239/179), White American participants played a money-sharing game with Black and White players, based on a probabilistic reward reinforcement learning task, in which they chose to interact with players and received feedback on whether a player shared. We found that participants formed stronger reward preferences for White relative to Black players despite equivalent reward feedback between groups-a pattern that was stronger among participants with low internal motivation to respond without prejudice and high explicit prejudice. This race effect in reward learning was evident in participants' behavioral choice preferences, but not in their self-reported perceptions of group members' reward rates. Computational modeling suggested two mechanisms through which race affected instrumental learning: race (a) influenced White participants' initial expectancies (i.e., priors) about Black compared with White players' behavior and (b) led participants to update reward representations of Black and White players according to separate learning rates. These findings demonstrate that race can influence the formation of impressions through direct social interaction and introduce an instrumental learning framework to understand the effects of bias in intergroup interactions. Public Significance Statement Race influences how people form impressions of others in the direction of social interactions through a process of instrumental learning, particularly among perceivers high in prejudice. Computational modeling reveals that this bias occurs because race influences perceivers' initial expectancies and how they learn from their partner's behavior.