Is it a norm to favour your own group?
通过两阶段分配实验，研究惩罚者身份如何影响对内群体偏袒行为的规范执行，发现内群体成员视偏袒为规范，外群体成员则予以惩罚，第三方旁观者不愿干预。
Abstract This paper examines the relationship between norm enforcement and in-group favouritism behaviour. Using a new two-stage allocation experiment with punishments, we investigate whether in-group favouritism is considered as a social norm in itself or as a violation of a different norm, such as egalitarian norm. We find that which norm of behaviour is enforced depends on who the punisher is . If the punishers belong to the in-group, in-group favouritism is considered a norm and it does not get punished. If the punishers belong to the out-group, in-group favouritism is frequently punished. If the punishers belong to no group and merely observe in-group favouritism (the third-party), they do not seem to care sufficiently to be willing to punish this behaviour. Our results shed a new light on the effectiveness of altruistic norm enforcement when group identities are taken into account and help to explain why in-group favouritism is widespread across societies.