Akdeniz Aslihan, van Veelen Matthijs
University of Amsterdam, Roetersstraat 11, 1018 WB Amsterdam, The Netherlands.
Tinbergen Institute, Gustav Mahlerplein 117, 1082 MS Amsterdam, The Netherlands.
Evol Hum Sci. 2021 Jul 22;3:e41. doi: 10.1017/ehs.2021.36. eCollection 2021.
A considerable share of the literature on the evolution of human cooperation considers the question why we have not evolved to play the Nash equilibrium in prisoners' dilemmas or public goods games. In order to understand human morality and pro-social behaviour, we suggest that it would actually be more informative to investigate why we have not evolved to play the subgame perfect Nash equilibrium in sequential games, such as the ultimatum game and the trust game. The 'rationally irrational' behaviour that can evolve in such games gives a much better match with actual human behaviour, including elements of morality such as honesty, responsibility and sincerity, as well as the more hostile aspects of human nature, such as anger and vengefulness. The mechanism at work here is commitment, which does not need population structure, nor does it need interactions to be repeated. We argue that this shift in focus can not only help explain why humans have evolved to know wrong from right, but also why other animals, with similar population structures and similar rates of repetition, have not evolved similar moral sentiments. The suggestion that the evolutionary function of morality is to help us commit to otherwise irrational behaviour stems from the work of Robert Frank (, (4), 593-604, 1987; , WW Norton, 1988), which has played a surprisingly modest role in the scientific debate to date.
为何我们在囚徒困境或公共物品博弈中没有进化到采用纳什均衡。为了理解人类道德和亲社会行为，我们认为，实际上更具启发性的做法是研究为何我们在序贯博弈（如最后通牒博弈和信任博弈）中没有进化到采用子博弈完美纳什均衡。在这类博弈中能够进化出的“理性的非理性”行为，与实际人类行为更为契合，包括诚实、责任和真诚等道德元素，以及人性中更具敌意的方面，如愤怒和报复心。这里起作用的机制是承诺，它既不需要群体结构，也不需要互动重复进行。我们认为，这种关注点的转变不仅有助于解释人类为何进化到能够明辨是非，还能解释为何其他具有相似群体结构和相似重复率的动物没有进化出类似的道德情感。道德的进化功能是帮助我们对原本不理性的行为做出承诺，这一观点源于罗伯特·弗兰克的研究（《经济学季刊》，第102卷，第4期，第593 - 604页，1987年；WW诺顿出版社，1988年），然而迄今为止，该观点在科学辩论中所起的作用却出人意料地有限。
