Just a Big Misunderstanding? Bias and Bayesian Affective Polarization

29 Pages Posted: 22 May 2020

See all articles by Daniel F. Stone

Daniel F. Stone

Bowdoin College - Department of Economics

Multiple version iconThere are 2 versions of this paper

Date Written: February 2020


I present a model of affective polarization—growth in hostility over time between two parties—via quasi‐Bayesian inference. In the model, two agents repeatedly choose actions. Each choice is based on a balance of concerns for private interests and the social good. More weight is put on private interests when an agent's character is intrinsically more self‐serving and when the other agent is believed to be more self‐serving. Each agent Bayesian updates about the other's character, and dislikes the other more when she is perceived as more self‐serving. I characterize the effects on growth in dislike of three biases: a prior bias against the other agent's character, the false consensus bias, and limited strategic thinking. Prior bias against the other's character remains constant or declines over time, and actions do not diverge. The other two biases cause actions to become more extreme over time and repeatedly be “worse” than expected, causing mutual growth in dislike, that is, affective polarization. The magnitude of dislike can become arbitrarily large—even when both players are arbitrarily “good” (unselfish). The results imply that seemingly irrelevant cognitive biases can be an important cause of the devolution of relationships, in politics and beyond, and that subtlety and unawareness of bias can be key factors driving the degree of polarization.

Suggested Citation

Stone, Daniel F., Just a Big Misunderstanding? Bias and Bayesian Affective Polarization (February 2020). International Economic Review, Vol. 61, Issue 1, pp. 189-217, 2020, Available at SSRN: https://ssrn.com/abstract=3602120 or http://dx.doi.org/10.1111/iere.12421

Daniel F. Stone (Contact Author)

Bowdoin College - Department of Economics ( email )

Brunswick, ME 04011
United States
6463387833 (Phone)

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