2009 年 80 巻 3 号 p. 246-251
Recent research has suggested that two distinct psychological processes lead to ingroup favoritism in the minimal group paradigm (MGP) : the motivation to gain positive intergroup distinctiveness, and the motivation to maintain intragroup cooperation. In this study, we tested a hypothesis based on the adaptationist perspective, that different situational cues suggesting intergroup threat or intragroup interdependence would elicit ingroup favoritism via these distinct psychological processes. Ninety-one Japanese undergraduates participated in a minimal group experiment and performed a reward allocation task. The results supported our predictions. Participants did not show ingroup favoritism in the control condition, where only pure ingroup-outgroup categorization was made. However, they showed ingroup favoritism when they were exposed to intergroup threat in an ostensibly unrelated task prior to reward allocation (intergroup threat condition). Moreover, a positive correlation between ingroup favoritism and the motivation to maximize positive intergroup distinctiveness was observed only in the intergroup threat condition. Likewise, participants showed ingroup favoritism in the interdependence condition, where they were presented with cues suggesting interdependence within the ingroup. The significance and implications of the findings are discussed.