Distrust in Experts and the Origins of Disagreement

Disagreement about the state of the world and expert credibility often go together in areas such as economics, climate change, and medicine. We argue this occurs because individuals make a mistake we call pre-screening when determining how much weight give an expert's signals. A pre-screener mistakes credibility as a primitive of the model and uses the signals to learn about credibility before forming posterior beliefs. Pre-screening predicts that disagreement about credibility is correlated with disagreement about the state. Furthermore: 1) Differing first impressions about credibility create persistent disagreement about the state; 2) Encountering experts in different order generates disagreement; and 3) Confirmation bias, overconfidence, and their opposites endogenously arise. These effects arise even when individuals share common priors, information, and learning errors, providing a theory of the origins of disagreement.