School of Mathematics, University of Bristol, Bristol BS8 1TW, UK.
Nat Commun. 2015 Jan 20;6:6134. doi: 10.1038/ncomms7134.
One possible explanation for the widespread existence of cooperation in nature is that individuals cooperate to establish reputations and so benefit in future interactions with others. We consider a class of games in which individuals contribute to a common good at a cost to themselves. Population members vary in type, that is, in the cost paid for a given level of contribution. We consider a form of indirect reciprocity in which the contribution of an individual depends on their partner's reputation and their own type. Here we show that for such games, reputation destabilizes the selfish equilibrium through a novel and robust feedback mechanism. For those games in which the selfish optimal contribution to the common good increases as the contribution of the partner increases, the feedback mechanism enhances cooperation levels. In contrast, when the optimal contribution decreases as partner's contribution increases, cooperation levels are reduced still further.
自然界中合作广泛存在的一个可能解释是，个体通过合作来建立声誉，从而在未来与他人的互动中受益。我们考虑了一类游戏，其中个体以自身的代价为共同利益做出贡献。群体成员在类型上存在差异，即对于给定的贡献水平，他们付出的代价不同。我们考虑了一种间接互惠形式，其中个体的贡献取决于他们的伙伴的声誉和他们自己的类型。在这里，我们表明，对于这种游戏，声誉通过一种新颖而稳健的反馈机制破坏了自私的均衡。对于那些自私的最优贡献随着伙伴的贡献增加而增加的共同利益游戏，反馈机制增强了合作水平。相比之下，当最优贡献随着伙伴的贡献增加而减少时，合作水平进一步降低。
