Social contact patterns can buffer costs of forgetting in the evolution of cooperation

Analyses of the evolution of cooperation often rely on two simplifying assumptions: (i) individuals interact equally frequently with all social network members and (ii) they accurately remember each partner's past cooperation or defection. Here, we examine how more realistic, skewed patterns of contact---in which individuals interact primarily with only a subset of their network's members---influence cooperation. In addition, we test whether skewed contact patterns can counteract the decrease in cooperation caused by memory errors (i.e., forgetting). Finally, we compare two types of memory error that vary in whether forgotten interactions are replaced with random actions or with actions from previous encounters. We use evolutionary simulations of repeated prisoner's dilemma games that vary agents' contact patterns, forgetting rates, and types of memory error. We find that highly skewed contact patterns foster cooperation and also buffer the detrimental effects of forgetting. The type o...

合作演化的相关分析通常依赖两项简化假设：其一，个体与所有社交网络（social network）成员的互动频率均等；其二，个体能够准确记忆每一位过往合作伙伴的合作或背叛行为。
本研究探讨了更贴合现实的偏态接触模式——即个体的互动主要集中于社交网络中的部分成员——对合作行为的影响。此外，我们还检验了偏态接触模式能否抵消由记忆错误（memory errors，即遗忘）所引发的合作水平下降。最后，我们对比了两类记忆错误的差异：两类错误的区别在于，被遗忘的互动行为会被随机行动替代，还是被过往互动中的行动所替代。
本研究采用重复囚徒困境博弈（repeated prisoner's dilemma games）的演化模拟（evolutionary simulations）方法，模拟中可调整智能体（agent）的接触模式、遗忘速率以及记忆错误类型。研究结果显示，高度偏态的接触模式能够促进合作，同时还可缓冲遗忘带来的负面影响。而该类……