Social Identity and Punishment

Third party (bystander) punishment is crucial for sustaining cooperative behavior. Through laboratory experiments we investigate the interaction between group identi - cation and a bystander's punishment preferences by inducing minimal groups and giving a bystander the opportunity to levy a xed amount of punishment on the perpetrator of an unfair act towards a defenseless victim. We elicit the bystander's valuation for punishment in four cases: when the perpetrator, the victim, both or neither are members of the bystander's group. For predictions, we construct three separate frameworks di ering by whether the primary e ect of group identity is to create an empathetic bond between in-group members or to a ect the weights placed on others' money earnings (distributional social preferences). The frameworks yield starkly di erent ordinal predictions about the bystander's value for punishment across two cases: i) when the perpetrator and victim are both members of the bystander's group; ii) when only the victim is an in-group member. The empathetic bond framework predicts that punishment will be more highly valued in the latter case, while the distributional preferences frameworks suggest the opposite. Our data support the predictions of the rst. Finally, we conduct control sessions where groups are not induced and nd that bystanders tend to treat others as in-group members unless speci cally divided into distinct groups.