Morality, Outgroups, and Politics

Moral differences between Democrats and Republicans contribute to affective polarization, or how negatively each side feels toward one another. Partisans are also generally aware of and sensitive to which social groups comprise the other political party. The present study examines if changes to the United States population, and thus levels of support for the two parties, will influence affective polarization. To do so, participants were randomly assigned to one of two treatment conditions in which they read about demographic changes reported in the 2020 U.S. Census, or a control condition. I find that the treatment conditions did not have a main effect for how partisans felt toward the outparty or its supporters, and only limited evidence that treatment effects were moderated by partisans’ collective moral values (i.e., normative expectations for society as a whole). However, I do find that the strength of collective moral values predicted the degree to which partisans disliked the other side, albeit only for the parties themselves and not their supporters. Altogether, this study provides evidence for the role of moral values in heightened political polarization, and offers a discussion of how to effectively measure the ways in which people might respond to demographic change information, specifically as a form of intergroup threat. Advisor: Elizabeth Theiss-Morse