Third-party fairness maintenance in five types of group relationships

To find out if third-party fairness maintenance is affected by group relationships, we divided participants into three groups and had them play a game of third-party fairness maintenance, in which a third party chooses between keeping (not intervening), punishing, or compensating, when the other players face unfair dictator game results. Results show that when faced with in-group unfair events, the third party tended to choose keeping or compensating strategies, and to opt not to intervene in the unfair events of the out-group. This tendency was stronger when both the dictator and the recipient belonged to the same out-group. In addition, there was intergroup bias in maintenance of third-party fairness. When the violator was an in-group member, the third party tended to use keep and compensate strategies, and chose to punish when facing violation by the out-group. Our findings illustrate the influence of group relationships on third-party fairness maintenance.