In-group favouritism in multiple social category contexts: extending generosity towards out-group members

Intergroup prosocial behaviour can potentially help us solve intergroup conflicts, but in-group favouring behaviour hinders building a cooperative relationship between different groups. However, why individuals favour in-group members over out-group members has not been well understood, and ways to reduce discrimination in prosocial behaviour have not been sought either. The present research first aimed to elucidate the mechanism of parochial prosocial behaviour (Study 1 and Study 2). Secondly, it tested the hypothesis that individuals would treat partial out-group members more favourably than out-group members, which would help reduce intergroup discrimination (Pilot study, Study 1, and Study 2). Overall, it found support for the group neutral increased prosociality perspectives (Study 1) which assumes that both social identity and reputational concern shape intergroup prosocial behaviour. Previously dominant theories concerning in-group favouritism such as the social identity theory approach (Tajfel & Turner, 1979) and bounded generalized reciprocity (Yamagishi, Jin, & Kiyonari, 1999) were not supported. In addition, the pilot study and Study 1 provided evidence in favour of the hypothesis, but not in Study 2. Discrepancies in findings among those studies were discussed. The research provides theoretical implications for future research concerning in-group favouring behaviour, suggesting possible key issues that will help further elucidate parochialism. Furthermore, the finding that individuals extend in-group favouring behaviour towards partial out-group members is of practical importance as it will potentially reduce intergroup discrimination.