野球チームのファンの内集団協力に関する場面想定法実験

抄録

This study aimed to test the validity of social identity theory (SIT) and bounded generalized reciprocity hypothesis (BGR) to explain ingroup cooperation in real social groups. Each of the validity of SIT and BGR have been discussed by social psychologists for a long time. However, recent studies indicate that both theories could explain ingroup cooperation simultaneously. Nakagawa et al. (2015) showed that ingroup cooperation among Japanese fans of a baseball team was derived from the psychological mechanisms predicted by both theories. The present study tested the reproducibility of these results when the cost of cooperation was emphasized. Japanese fans of all 12 baseball teams (N = 1,635) participated in this experiment. In each scenario, the cost of helping was emphasized, and reciprocal expectation was manipulated by knowledge about the feeling of belonging by participants and their partner’s group. The results showed that ingroup cooperation was shown by the psychological mechanism of BGR more than SIT when the cost of cooperation was emphasized.