According to inclusive fitness theory, people are more willing to help those they are genetically related to because relatives share a kin altruism gene and are able to pass it along. We tested this theory by examining the effect of reproductive potential on altruism. Participants read hypothetical scenarios and chose between cousins (Studies 1 and 2) and cousins and friends (Study 3) to help with mundane chores or a life-or-death rescue. In life-or-death situations, participants were more willing to help a cousin preparing to conceive rather than adopt a child (Study 1) and a cousin with high rather than low chance of reproducing (Studies 2 and 3). Patterns in the mundane condition were less consistent. Emotional closeness also contributed to helping intentions (Studies 1 and 2). By experimentally manipulating reproductive potential while controlling for genetic relatedness and emotional closeness, we provide a demonstration of the direct causal effects of reproductive potential on helping intentions, supporting the inclusive fitness explanation of kin altruism.

中文翻译：

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具有更大生殖潜力的亲戚会首先获得帮助吗？：对亲属利他主义的包容性适应性解释的测试。

根据包容性适应理论，人们更愿意帮助那些与自己有血缘关系的人，因为亲属共享亲属利他主义基因，并且能够将其传递下去。我们通过研究生殖潜力对利他主义的影响来检验这一理论。参与者阅读假设的场景，并在表兄弟姐妹（研究 1 和 2）以及表兄弟姐妹和朋友（研究 3）之间进行选择，以帮助处理日常琐事或生死攸关的救援。在生死攸关的情况下，参与者更愿意帮助准备怀孕的表亲而不是收养孩子（研究1），以及生育机会高而不是低的表亲（研究2和3）。平凡条件下的模式不太一致。情感上的亲密也有助于帮助意图（研究 1 和 2）。通过实验性地操纵生殖潜力，同时控制遗传相关性和情感亲密性，我们证明了生殖潜力对帮助意图的直接因果影响，支持亲属利他主义的包容性适应性解释。