Learning by observing the past decisions of others can help explain some otherwise puzzling phenomena about human behavior. For example, why do people tend to converge on similar behavior? Why is mass behavior prone to error and fads? The authors argue that the theory of observational learning,...

An informational cascade occurs 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. We argue that localized conformity of behavior and the fragility of mass behaviors...

Consider a mechanism design setting in which agents acquire costly information about an unknown, payoff-relevant state of nature. Information gathering is covert. We investigate conditions under which (i) efficient implementation and (ii) full surplus extraction are Bayesian incentive compatible...