Aggregate Uncertainty Can Lead to Incorrect Herds
研究在总体不确定性下，理性代理人如何通过观察他人选择形成羊群行为，并可能错误地选择劣质技术，对理解金融市场中的非理性现象有参考价值。
A continuum of homogeneous rational agents choose between two competing technologies. Agents observe a private signal and sample others' previous choices. Signals have an aggregate component of uncertainty, so aggregate behavior does not necessarily reflect the true state of nature. Nonetheless, agents still find others' choices informative, and base their decisions partly on others' behavior. Consequently, bad choices can be perpetuated: aggregate uncertainty makes agents herd on the inferior technology with positive probability. I derive the optimal decision rule when agents sample exactly two individuals. I also present examples with herds on the inferior technology for arbitrarily large sample sizes.