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Just a Big Misunderstanding? Bias and Affective Polarization

47 Pages Posted: 9 Apr 2016 Last revised: 17 Jun 2017

Daniel F. Stone

Bowdoin College - Department of Economics

Date Written: June 15, 2017


I propose and test a model of affective polarization ("that both Republicans and Democrats increasingly dislike, even loathe, their opponents," Iyengar et al, 2012). In the model, two agents, representing the parties, repeatedly choose actions based on private interests, the social good, their own "character" (willingness to trade private for social gains) and beliefs about the other agent's character. Each agent Bayesian updates about the other's character, and dislikes the other more when its character is perceived as more self-serving. I study the dynamic and long-run effects of two biases that seem unrelated to character: the false consensus bias and limited strategic thinking. Each causes actions to become more extreme over time leading to affective polarization. Despite Bayesian updating, the magnitude of dislike can be arbitrarily large---even when both players are arbitrarily "good." Both biases are in part caused, and have effects exacerbated, by overconfidence in beliefs (overprecision), and thus the model suggests overprecision is a more general factor driving affective polarization. Using representative survey data, I show that overprecision indeed predicts higher out-party hostility, conditional on controls for ideological extremism, strength of partisanship, perceived distance between the parties, and motivated reasoning. I argue that the results help explain the development of hostility between well-meaning people in more general contexts.

Keywords: affective polarization, partyism, polarization, disagreement, dislike, over-precision, unawareness, motivated reasoning, media bias

JEL Classification: D64, D72, D83

Suggested Citation

Stone, Daniel F., Just a Big Misunderstanding? Bias and Affective Polarization (June 15, 2017). Available at SSRN:

Daniel Stone (Contact Author)

Bowdoin College - Department of Economics ( email )

Brunswick, ME 04011
United States
6463387833 (Phone)

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