Code for: Ideological Bias and Trust in Information Sources

We study the role of endogenous trust in amplifying ideological bias. Agents in our model learn a sequence of states from sources whose accuracy is ex ante uncertain. Agents learn these accuracies by comparing their own reasoning about the states based on introspection or direct experience to the sources’ reports. Small biases in this reasoning can cause large ideological differences in the agents’ trust in information sources and their beliefs about the states, and may lead agents to become overconfident in their own reasoning. Disagreements can be similar in magnitude whether agents see only ideologically aligned sources or diverse sources.