Document Type



Many theorists claim that social media contribute to political polarization, but it is not clear how these effects occur. We propose and explain a theoretical model of this process that focuses on moral outrage. This combination of anger and disgust can emerge from a mismatch between evolved human nature and certain features of political discussions on the internet. We identify three specific types of socially negative behavior that moral outrage facilitates: aggression (behavior intended to harm others), sophistry (poor argumentation), and withdrawal (avoiding discussions of politics). We describe psychological mechanisms through which moral outrage can lead to these outcomes, specifically focusing on dehumanization and group antagonism. We discuss research justifying our proposed model and suggest new ways to empirically test its links. Our model should be useful for researchers exploring the question of when and how political discussions on social media go wrong as well as what to do about these problems.