Kurokawa Shun
Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan; Key Lab of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, P. R. China.
Math Biosci. 2017 Apr;286:94-103. doi: 10.1016/j.mbs.2017.02.006. Epub 2017 Feb 14.
One key potential explanation for the evolution of cooperation is conditional cooperation. This allows cooperation to evolve for cooperators who switch their behavior on the basis of information about the opponent's behavior or reputation. However, information about the opponent's behavior or reputation is sometimes unavailable, and previous studies have assumed that a player cooperates with some default probability when no information about the opponent's previous behavior or reputation is available. This default probability has been interpreted as the player's "optimism". Here, we make use of the fact that even if a player cannot observe the opponent's previous behavior or reputation, he may still condition his future behavior based on his own past behavior and in such a case, he can behave persistently. In this paper, we especially consider the case where information about the opponent's "behavior" is sometimes absent and the iterated prisoner's dilemma game between the same two individuals is played. Here, we examine the evolution of strategies that can refer to the own behavior in the previous round. Using evolutionarily stable strategy (ESS) analysis and analyzing replicator dynamics, we find that conditioning his future behavior based on his own past behavior is beneficial for the evolution. Persistence facilitates the evolution of cooperation.
合作进化的一个关键潜在解释是条件性合作。这使得合作能够在那些根据对手行为或声誉信息来改变自身行为的合作者中得以进化。然而，关于对手行为或声誉的信息有时是无法获取的，并且先前的研究假定，当没有关于对手先前行为或声誉的信息时，玩家会以某种默认概率进行合作。这种默认概率被解释为玩家的“乐观程度”。在此，我们利用这样一个事实：即使玩家无法观察到对手先前的行为或声誉，他仍然可以根据自己过去的行为来调整未来的行为，在这种情况下，他可以表现出持续性。在本文中，我们特别考虑这样一种情形，即有时缺乏关于对手“行为”的信息，且同一对个体之间进行重复囚徒困境博弈。在此，我们研究能够参考上一轮自身行为的策略的进化情况。通过进化稳定策略（ESS）分析并分析复制动态，我们发现根据自己过去的行为来调整未来行为对进化是有益的。持续性促进了合作的进化。
