Theoretical Economics, Volume 12, Number 3 (September 2017)

Theoretical Economics 12 (2017), 1155–1189


Active learning with a misspecified prior

Drew Fudenberg, Gleb Romanyuk, Philipp Strack

Abstract


We study learning and information acquisition by a Bayesian agent whose prior belief is misspecified in the sense that it assigns probability zero to the true state of the world. At each instant, the agent takes an action and observes the corresponding payoff, which is the sum of a fixed but unknown function of the action and an additive error term. We provide a complete characterization of asymptotic actions and beliefs when the agent's subjective state space is a doubleton. A simple example with three actions shows that in a misspecified environment a myopic agent's beliefs converge while a sufficiently patient agent's beliefs do not. This illustrates a novel interaction between misspecification and the agent's subjective discount rate.

Keywords: Active learning, learning in games, mis-specified models

JEL classification: D83,D90

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