Learning from financial rewards and punishments reduces the ingroup bias in social approach without changing the ingroup bias in impressions

Humans’ approach behavior and impressions are biased towards individuals from their own group (ingroup) compared to different groups (outgroup). There is evidence that learning from specific interactions with ingroup and outgroup members can reduce these ingroup biases, but it is yet unclear if learning from non-social reinforcers such as financial rewards and punishments can have similar effects. Here, we conducted three independent studies by using different versions of a novel approach-avoidance learning task, intergroup impression ratings, and computational learning models. In the approach-avoidance learning task, participants moved a manikin representing themselves towards or away from one of two symbols, representing ingroup or outgroup individuals or which had no social meaning. Approach was financially rewarded with varying probabilities. Our results confirmed initial ingroup biases in approach and impression ratings. Rewarding outgroup approach significantly reduced the ingroup bias in approach with stronger learning from rewards compared to punishments. In contrast, the ingroup bias in impressions remained unchanged. Two further studies showed that learning-related changes in approach are larger in social compared to non-social contexts and require varying reward probabilities. Together, these findings show that learning from financial rewards or punishments can improve outgroup approach but not outgroup impressions.