Social norms and group-bounded indirect reciprocity

Indirect reciprocity is a reputation-based mechanism proposed to explain the evolution of human cooperation. Theoretical models demonstrated that the use of both first-order information (i.e., whether an evaluation target cooperated) and second-order information (i.e., the reputation of an interaction partner of the evaluation target) is critical for the evolution of cooperation. However, empirical findings on the use of second-order information have been mixed. Drawing upon the literature on group-bounded indirect reciprocity, we tested the hypothesis that individuals would be more sensitive to second-order information when evaluating in-group interactions, compared to when evaluating out-group interactions. We conducted a preregistered online experiment (N = 604), where we independently manipulated group membership (in-group vs. out-group), target behaviour (cooperation vs. defection), and recipient reputation (good vs. bad). We found that donors who defected against good recipients were rated more negatively than those who defected against bad recipients, indicating the use of second-order information. Partly consistently with our hypothesis, when individuals evaluated coopering donors, second-order information influenced reputation for in-group donor-recipient interactions more than for out-group donor-recipient interactions. Nevertheless, individuals readily used second-order information, whether or not they evaluated in-group or out-group donor-recipient interactions.