One bad apple? Heterogeneity and information in public good provision
通过实验识别参与者的社会偏好类型，研究群体中自私个体的数量如何影响合作与效率，发现自私者不仅自己贡献少，还会降低条件合作者的贡献。
Abstract Previous research demonstrates that individuals vary in their social preferences. Less well-understood is how group composition affects the behavior of different social preference types. Does one bad apple really spoil the bunch? This paper exogenously identifies experimental participants’ social preferences, then systematically assigns individuals to homogeneous or heterogeneous groups to examine the impact of ‘bad apples’ on cooperation and efficiency. Consistent with previous research, we find that groups with more selfish types achieve lower levels of efficiency. We identify two mechanisms for the effect. First, the selfish players contribute less. Second, selfish players induce lower contributions from the conditional cooperators, and this effect increases in the number of selfish players. These results are not sensitive to information about the distribution of types in the group.