Abstract Emergence of characteristically human traits, including extensive collaboration, prosociality, and cooperative communication, has presumably necessitated evolution toward lower aggression. While empirical studies have provided evidence for evolutionary reduction in human aggression, such as canine teeth reduction in hominins and craniofacial feminization in Homo sapiens , the underlying mechanisms for the reduction in human aggression are virtually unknown. A promising hypothesis is social selection by partner choice; that is, individuals’ choice of collaborative partners may have induced selection against exceedingly aggressive individuals. However, it is thus far unclear whether partner choice can give unaggressive individuals a fitness benefit that more than compensates for the lost advantage of being aggressive in interindividual conflict. This study explores the plausibility of the social selection hypothesis, using a game-theoretic model of coalition formation. Analysis of the game shows that partner choice can induce selection favoring reduced fighting ability if individuals are ecologically demanded to collaborate, they can be viewed as rational fitness maximizers, and they have communicative skills to bring a synergy in collaboration. The model also suggests a possible feedback loop between reduction of fighting ability and a correlated enhancement of communicative skills. Significance statement Domesticated animals often share a suite of morphological, physiological, and cognitive characteristics, called the domestication syndrome, that are distinct from their wild ancestors. Experimental studies have shown that the domestication syndrome can arise as a by-product of selection against aggressiveness. A similar process may occur in wild animals; in particular, it has been suggested that “self-domestication” through selection against aggression may have played a major role in human evolution. Despite the proposed role of reduced aggression, however, it is thus far unclear in what ecological context less aggressive individuals can be selectively favored over more aggressive ones. This study provides a theoretical foundation for the social selection hypothesis for the evolution of reduced aggression, using a game-theoretic model of coalition formation, and specifies the conditions under which individuals’ choice of collaborative partners can induce selection favoring reduced aggression.

中文翻译：

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有利于减少攻击性的社会选择的数学模型

摘要 人类特征的出现，包括广泛的合作、亲社会性和合作交流，可能需要向低攻击性进化。虽然经验研究已经为人类攻击性的进化减少提供了证据，例如人类的犬齿减少和智人的颅面女性化，但人类攻击性减少的潜在机制实际上是未知的。一个有希望的假设是伴侣选择的社会选择；也就是说，个人对合作伙伴的选择可能会导致对过于激进的个人的选择。然而，迄今为止，尚不清楚伴侣的选择是否能给不具攻击性的个体带来健康益处，而不仅仅是弥补在个体间冲突中具有攻击性所失去的优势。本研究使用联盟形成的博弈论模型探讨了社会选择假说的合理性。博弈分析表明，如果个体在生态上需要协作，则合作伙伴选择可以诱导选择有利于降低战斗能力，他们可以被视为理性的适应度最大化者，并且他们具有交际技巧以在协作中带来协同作用。该模型还提出了战斗能力降低和沟通技巧相关增强之间可能存在的反馈循环。意义说明 家养动物通常共享一套形态、生理、和认知特征，称为驯化综合症，与它们的野生祖先不同。实验研究表明，驯化综合症可能是针对攻击性进行选择的副产品。类似的过程可能发生在野生动物身上；特别是，有人提出通过选择对抗侵略的“自我驯化”可能在人类进化中发挥了重要作用。然而，尽管提出了减少攻击性的作用，但目前尚不清楚在什么生态环境中，攻击性较小的个体可以被选择性地偏爱于攻击性较强的个体。本研究使用联盟形成的博弈论模型，为减少攻击性演变的社会选择假说提供了理论基础，