Communication and Learning

We study strategic information transmission in an organization consisting of an infinite sequence of individual decision makers. Each decision maker chooses an action and receives an informative but imperfect signal of the once-and-for-all realization of an unobserved state. The state affects all individuals' preferences over present and future decisions. Decision makers do not directly observe the realized signals or actions of their predecessors. Instead, they must rely on cheap-talk messages in order to accumulate information about the state. Each decision maker is therefore both a receiver of information with respect to his decision, and a sender with respect to all future decisions. We show that if preferences are not perfectly aligned "full learning" equilibria - ones in which the individuals' posterior beliefs eventually place full weight on the true state - do not exist. This is so both in the case of private communication, in which each individual only hears the message of his immediate predecessor, and in the case of public communication, in which a decision maker hears the message of all his predecessors. Surprisingly, in the latter case full learning may be impossible even in the limit as all members of the organization become infinitely patient. We also consider the case where all individuals have access to a mediator who can work across time periods arbitrarily far apart. In this case full learning equilibria exist.