Evolutionary definitions of altruism are only concerned with reproductive consequences and not motives or other psychological mechanisms, making them ideal for generalization to all forms of organisms. Hamilton’s inclusive fitness theory explains altruistic behavior toward genetic relatives and has generated extensive empirical support. Trivers’ theory of reciprocal altruism helps explain patterns of helping among non-kin, and other research has demonstrated that human helping intentions follow fitness consequences from age-based reproductive value on altruism. The current study examines a novel psychological factor, belief in the afterlife, which may influence altruistic helping intentions. Belief in the afterlife was incorporated into a previous study design assessing the effects of a target’s genetic relatedness and age-based reproductive value. The influences of inclusive fitness and target age were reproduced in a non-Western sample of participants (N = 300) in Iran. Belief in the afterlife predicted the overall confidence of risking one’s life to save another across all targets, and also moderated the effects of genetic relatedness and target age. Rather than promoting altruism equitably or advantaging those favored by adaptive tendencies, higher belief in an afterlife aligned with these tendencies in promoting further favoritism toward close kin and younger targets with higher reproductive value.

利他主义的进化定义只涉及生殖后果，而不涉及动机或其他心理机制，这使得它们非常适合推广到所有形式的生物体。汉密尔顿的包容性适应性理论解释了针对亲缘关系的利他行为，并得到了广泛的实证支持。特里弗斯的互惠利他主义理论有助于解释非亲属之间的帮助模式，而其他研究表明，人类的帮助意图遵循基于年龄的利他主义生殖价值的适应性结果。目前的研究探讨了一种新的心理因素，即对来世的信仰，它可能会影响利他的帮助意图。对来世的信仰被纳入之前的研究设计中，评估目标的遗传相关性和基于年龄的生殖价值的影响。在伊朗的非西方参与者样本（N = 300）中再现了包容性健身和目标年龄的影响。对来世的信仰预测了所有目标中冒着生命危险拯救他人的总体信心，并且还调节了遗传相关性和目标年龄的影响。对来世的更高信念与这些倾向相一致，而不是公平地促进利他主义或有利于那些受适应性倾向青睐的人，从而进一步促进对近亲和具有更高生殖价值的年轻目标的偏爱。