This paper studies how people react to rumors from the perspective of social networks. Before making decisions to match the state of a rumor, individuals in a social network decide whether to investigate the rumor's authenticity. An unusual signal, which could possibly be detected if the rumor is fake, is local public information. We show that an individual is a bystander when few linked neighbors investigate, is a free-rider when many neighbors are investigators, and becomes an investigator only when the number of linked neighbors falls in a certain range. We use the insulated set of a core of the network to characterize the set of investigators in an equilibrium that induces the least number of bystanders. Only those who belong to the core make decisions upon observed signals, while those outside the core make decisions based on prior belief in this equilibrium.

本文从社交网络的角度研究人们对谣言的反应。在做出与谣言状态相匹配的决定之前，社交网络中的个人会决定是否调查谣言的真实性。如果当地谣言是假的，则可能会检测到一个不寻常的信号。我们表明，当很少有联系的邻居进行调查时，一个人是旁观者；当许多邻居是调查员时，他是一个搭便车的人；只有当链接的邻居的数量在一定范围内时，该人才成为调查者。我们使用网络核心的绝缘集来表征调查员在均衡状态下的集合，该均衡导致最少的旁观者。只有那些属于核心的人才能根据观察到的信号做出决定，