信息瀑与协调失灵——一个基于网络外部性的经济理论的产生及其进展

Informational Cascade and Coordination Failure——A Survey of a Theory Based on Network Externality

经济行为人来自某行动的所得与采取同样行动的人的数量呈相关性时就存在网络外部效应,此时,人们的行动是互补的。若分散的私人信息不能有效加总,当决策者采取序列互补行动时,就会出现非理性的从众行为,当行动者放弃自己的私人信息而跟随前一个人的行动时,信息瀑就发生了。如果将行动置于不确定性、互补性和分散信息状态下,不论是否序列行动,都可能发生群体协调行为的失灵,这会导致帕累托无效率的结果、甚至灾难性的后果。

The effect of network externality will exist when there is a pertinence relation between the net value of an action taken by an economic person and the number of agents taking equivalent actions, which means the actions are complementary. When dispersed personal information cannot be effectively aggregated and agents take sequential complementary actions, irrational herding occurs. An informational cascade arises when it is optimal for an individual, having observed the actions of those ahead of him, to follow the behavior of the preceding individual without regard to his own information. Regardless of sequential actions, coordination among agents is likely to break down if their behaviors have three features-uncertainty, complementarities and dispersed information, which leads to a result of Pareto-inefficient equilibrium and even results in a disastrous consequence.