Strategic Misinformation : The Role of Heterogeneous Confirmation Bias

Why do politicians sometimes support evidently false claims, such as fake news and conspiracy theories, spreading among a minority of the electorate? We analyze this political supply of misinformation from the perspective of politicians’ electoral incentives. For this purpose, we construct a two-period electoral accountability model in which the incumbent politician decides whether to support or deny the truth about a particular issue and exerts effort for producing public goods. We show that the low-competent incumbent paradoxically has an electoral incentive to support misinformation, even if only a minority of voters believe the misinformation. The key to this paradoxical incentive is the heterogeneity of confirmation bias, a psychological bias that has been regarded as a determinant for people’s persistent acceptance of misinformation in the literature. We show that the low-competent politician denies the truth if and only if the variance in the distribution of confirmation bias among voters is sufficiently large. This result indicates that individual differences in psychological bias among voters play a key role in the political supply of misinformation