Not fair but acceptable… for us! Group membership influences the tradeoff between equality and utility in a Third Party Ultimatum Game

A substantial body of literature on economic games (e.g., the Ultimatum Game) has consistently demonstrated that individuals strongly reject unfairness even at the price of personal utility. In four experiments we investigated the influence of social categorization and membership on economic decision-making and inequality aversion. Specifically, we used a modified version of the Third Party Ultimatum Game, in which participants played the role of responder and were instructed to make decisions for themselves or another individual (i.e. the receiver of the economic offer) who was an ingroup or outgroup member. Experiments 1-2 (N = 173) showed that the participants were more likely to accept unequal-advantageous offers when the receivers were ingroup rather than outgroup members. Experiment 3 (N = 121) supported previous findings and suggested the intervening role played by perceived intergroup competition. Experiment 4 (N = 61) explored the effect boundary conditions. Findings revealed that, even when responder's utility is linked to the receiver's utility, the receiver's membership exerted its influence when the responders were highly identified with the ingroup. A final small-scale meta-analysis confirmed the robustness of our findings. Taken together, these results integrate research on economic decision-making and intergroup bias and suggest that the utility target's membership can resolve the conflict between inequality aversion and utility maximization.