What Information Drives Political Polarization? Comparing the Effects of In-group Praise, Out-group Derogation, and Evidence-based Communications on Polarization

This project differentiates between communication that praises one's political in-group (in-group praise), attacks the opposition (out-group derogation), or focuses on policy details (evidence based), testing their effects on network and attitude polarization. We begin with an agent-based model, which shows that congenial evidence-based exchanges polarize the network and the inclusion of identity-driven communications leads to greater polarization. Once out-group derogation reaches a certain threshold, the network of agents splits into two groups, yet the polarizing effects of in-group praise are yet stronger and emerge more rapidly (i.e., a lower threshold of in-group praise is needed to polarize the network). Using an experimental design on a sample of American partisans, we offer a partial validation of the model. In-group praise and out-group derogation polarize attitudes more than balanced evidence-based news, but not more than congenial evidence-based news. Identity-driven news also has no effects on affective polarization. This multidisciplinary evidence shows that the nature of political content matters.