Can Reference to Others’ Behaviour Foster a Cooperative Group in Intergroup Conflict Situations?

Abstract

This study examined the effect of others’ behaviour on ingroup cooperation in intergroup conflict situations. Following cultural group selection theory, reference to other group members’ behaviour enhances ingroup cooperation in these situations. The validity of the cultural group selection theory was confirmed using an evolutionary simulation and a vignette experiment. However, no empirical study has tested this theory in the lab to assess ingroup cooperative behaviour. Hence, this study conducted an experiment using a repeated public goods game with intergroup conflicts. In total, 132 Japanese undergraduates (54 references, 48 non-references, and 30 controls) participated in this study. Two three-person groups played a public goods game, and the group with the higher number of cooperators received a portion of the other group’s public goods (intergroup conflict). The situation in which participants could refer to the feedback in each game trial was manipulated: reference condition (informed other members’ decisions in a previous trial and the win/loss of intergroup conflict), non-reference condition (informed only win/loss), and control condition (no information). The results validated the hypothesis that ingroup cooperation is enhanced in situations where participants can refer to other members’ behaviour more than in other situations.