Essays on Belief Formation and Political Polarization

Abstract

This dissertation consists of essays in behavioral, experimental, and political economics. It studies why people form polarized and biased beliefs, and how these beliefs lead to politically-polarized behavior in public health. The first chapter constructs a new experimental design to show how people, when faced with new information, engage in motivated reasoning by distorting their inference in the direction of beliefs they are more motivated to hold. Its results show that motivated reasoning is widespread and helps explain persistent belief polarization along political dimensions about immigration, income mobility, racial discrimination, crime, gender-based math ability, climate change, and gun laws. The second chapter delves into the limits of motivated reasoning, showing that the bias is not a major factor in the absence of self-image concerns. It shows that people do not systematically motivatedly reason to think that the world is a better place for others. The third chapter, coauthored with Hunt Allcott, Levi Boxell, Jacob Conway, Matthew Gentzkow, and David Yang, studies the public-health implications for political polarization in beliefs and behavior. It shows in a survey that there are significant gaps between Republicans and Democrats in beliefs about the severity of the COVID-19 pandemic in the United States, and shows using smartphone data that areas with more Republicans engage in significantly less social distancing.