Résumé

We provide a model of ideological and affective polarization and partisan communication. To do so, we formalize influential results in political psychology showing that moral and political judgements are primarily based on intuitions and emotions, while reasoning serves to rationalize these intuitions and provide image as a reasonable, evidence-based decision-maker. Rationalizations are strategic complements, as an increase in rationalizations undermines the ability to critically judge others, and implies that actions become less informative of the true state. Contagion of self-serving political narratives occurs both among like-minded individuals

and among opposing political partisans. When agents are naive about their own rationalizations, the model generates both ideological polarization about facts and policies, and affective polarization where agents assign inappropriate motives to their opponents. We also analyze the strategic disclosure of narratives, and show that sharing convenient narratives between ingroup members (but not outgroup members) can increase belief bias. Our model sheds light on the origin of partisan disagreement about the consequences of public policies and matches empirical facts on polarization

Co-auteurs : Peter Schwardmann and Joel J. van der Weele

Informations pratiques