Constructing the Enemy: Noun and Generic Party Labels Predict Partisan Prejudice in Social Media Comments

Research suggests that affective polarization stems from social categorization processes: People sort themselves and others into political categories and perceive each other as either ingroup or outgroup members. This categorization forms the basis for intergroup conflict, producing dislike and distrust between groups. However, the consequences of categorization are not uniform but scale with a group’s perceived entitativity—the degree to which it is perceived as coherent and unified. Research on novel groups suggests that perceived entitativity is driven by how others label these groups. Using fine-tuned transformer models to automatically classify Facebook posts ( N = 45,780) and comments ( N = 769,684), we show that this effect also holds for established political groups. Specifically, posts containing noun labels (e.g., “Senate Republicans”) rather than adjective labels (e.g., “Republican senators”) and using these labels generically (e.g., “Democrats want”) rather than non-generically (e.g., “some Democrats want”) receive higher proportions of comments expressing partisan prejudice.