Identity Strength Leads to Out-Group Animus and Polarization

Abstract America is increasingly a polarized society. Party politics has become a form of tribalism by which Democrats and Republicans treat each other as a stigmatized out-group. Partisans shun close contact with opposing partisans and show no compunction when discriminating against opposing partisans in a variety of contexts. In this chapter, the authors explore the antecedents of polarization, focusing on identity strength and political tolerance as key predictors. Using American National Election Study (ANES) national surveys conducted between 1964 and 2020, the authors first document the significant increase in hostility toward the opposing party. They then show that hostility is significantly elevated among individuals with a strong sense of partisan identity. Surprisingly, they find that the question used to measure political tolerance in the ANES surveys has negligible effects on partisan animus. In closing, they consider the implications of extreme polarization for democratic politics.