Abstract
The standard approach of economic theory is to simplify, simplify, simplify. In many contexts, from experimentation to search to communication, this implies a state of the world that is often as simple as a single piece of information. Reality is much messier, and typically there is much that decision makers don’t know. This distinction is particularly stark in models of expert advice. The insight from classic models of cheap talk is that communication is imperfect when the expert is biased, and the outcome is both inefficient and unfavorable to the expert, whereas in practice, experts hold considerable power over uninformed decision-makers. We show that this dissonance is due to simplification of expertise in classic models. We introduce a model of expert advice in which the mapping from actions to outcomes is given by the realized path of a Brownian motion. We show in this environment that strategic communication can be efficient and highly favorable to the expert. Communication is efficient not despite the complexity, but rather because of it.