Affective Polarization Among Party Members: Experimental Evidence from Brazil

What are the main drivers of affective polarization among party members? How do political, cultural, and economic cues shape party members’ feelings of dislike toward competitors, perceptions of social distance, and levels of satisfaction with democracy? This paper addresses these questions by analyzing both observational and experimental data from an original, large-scale survey of Brazilian party members. We examine the extent to which political, cultural, and economic narrative disputes operate as triggers of affective polarization. Specifically, we explore how disagreements over issues such as abortion rights, support for tax increases to expand public services, and trust in the Judiciary contribute to hostility within the political landscape. Our findings indicate that animosity toward rival parties can be a powerful driver of political engagement. However, the mechanisms that sustain and intensify hostility toward political adversaries remain only partially understood. While existing research has documented rising affective polarization among mass publics, less is known about how these dynamics operate within party organizations and among politically engaged activists. This paper addresses this gap by examining how issue-based narratives and institutional cues shape distrust, social distance, and democratic attitudes among party members. Drawing on theories of affective polarization and social identity, we argue that party members are especially responsive to elite-framed political, cultural, and economic conflicts, as these cues reinforce in-group identity and sharpen perceptions of out-group threat. We focus on how disagreements over moral issues, redistributive policies, and institutional trust function as distinct but potentially complementary drivers of affective polarization. In particular, we assess whether conflicts surrounding abortion rights, taxation to expand public services, and evaluations of the Judiciary activate different forms of hostility, ranging from emotional dislike of rival parties to broader dissatisfaction with democratic institutions. By highlighting this contemporary feature of party activism in a country marked by the growing influence of anti-democratic leadership, this study contributes to ongoing debates about the challenges democratic systems face amid the rise of the far right.