Talking with an Extremist

Abstract

Two agents announce the state they consider most likely infinitely many times. A small departure from common belief in rationality can have a severe impact on the belief about the state and on the behavior of an extremist: while initial periods of disagreement produce a temporary convergence of beliefs, prolonged disagreement induces reversion towards the initial belief. The mechanism is simple: the longer the counterpart insists on the opposite view, the more the extremist doubts that the counterpart is intellectually capable and honest, and therefore the more he discounts the counterpart's opinion.

Keywords: disagreement, almost common belief, polarization, misspecification, bounded rationality

JEL Classification: D83