Conditional Cooperation and Voluntary Contributions to Public Goods
实验比较了固定小组（伙伴组）和轮换小组（陌生人组）在重复公共物品博弈中的贡献差异，发现伙伴组贡献更高且波动较大，陌生人组贡献持续下降，行为可用条件合作解释。
We compare a partners condition , where the same small group of subjects plays a repeated public good game, to a strangers condition , where subjects play this game in changing group formations. From the first period onward, subjects in the partners condition contribute significantly more to the public good than subjects in the strangers condition. Strangers' contributions show continual decay, while partners' contributions fluctuate on a high level prior to decreasing in the final periods. We interpret subjects' behaviour in terms of conditional cooperation which is characterized by both future‐oriented and reactive behaviour. JEL classifications: C 91; C 92; H 41