Political Overconfidence Inhibits the Effectiveness of Inoculations Against Misperceptions

In this study, I develop an experimental framework to examine whether political overconfidence leads Americans to defend political misperceptions. Politically overconfident Americans, who suffer from the “double bind” of ignorance described by the Dunning-Kruger Effect, are expected to resist the effects of corrective inoculations against misperceptions. In two survey experiments, I measure political overconfidence, and assess its effects on skepticism towards five common misperceptions. In one study, I randomly expose respondents to an inoculation message, and observationally assess the effects of political overconfidence on the inoculation’s effectiveness. In a second study, I experimentally manipulate overconfidence itself, by exposing a random subset of respondents to an objective assessment of their political knowledgeability before random exposure to an inoculation. Together, the results show that corrective inoculations can reduce support for misperceptions. However, among the politically overconfident, these treatments are ineffective.