We provide an evolutionary explanation for the well-established evidence of the existence of in-group favoritism in intergroup conflict. Using a model of group contest for a (local) public good, we show that the larger the number of groups competing against one another, or the larger the degree of complementarity between individual efforts, the more likely are group members altruistic towards their teammates under preference evolution.

中文翻译：

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在（本地）公共产品的群体间冲突中，进化上稳定的群体内利他主义

我们为组间冲突中存在组内偏爱的确凿证据提供了进化论的解释。使用针对（本地）公共物品的小组竞赛模型，我们表明，互相竞争的小组越多，或者个人努力之间的互补程度越大，小组成员就越有可能对自己的队友表现出无私的态度。偏好演化。