HELPING BEHAVIOR IN LARGE SOCIETIES
研究在匿名随机配对的大社会中，即使存在从不帮助的个体，如何通过一种接近“以牙还牙”的线性均衡策略维持助人行为，对理解大规模社会合作机制有参考价值。
This article investigates how helping behavior can be sustained in large societies in the presence of agents who never help. I consider a game with many players who are anonymously and randomly matched every period in pairs. Within each match, one player may provide socially optimal but individually costly help to the other player. I introduce and characterize the class of “linear equilibria” in which, unlike equilibria used in the previous literature, there is help even in the presence of behavioral players. Such equilibria are close to a tit‐for‐tat strategy and feature smooth help dynamics when the society is large.