Proceedings of the Annual Meeting of the Cognitive Science Society

Political polarization is intensifying globally, with social media influencing social sorting by amplifying ideological extremes and reinforcing segregation. Recent work suggests that one driver of polarization is the fact that individuals preferentially engage with co-partisans who hold more extreme views than themselves. This study examines whether this tendency generalizes across countries and which perceptions are associated with it. We conducted a preregistered online study across five countries (United States, Chile, Germany, South Africa, and Australia; N = 1,199). Participants evaluated fictional social media profiles, locally adapted and validated, that varied in ideological extremity and reported their likelihood of following each profile. Across countries, participants preferred extreme over moderate ingroup profiles. This tendency was associated with perceiving extreme profiles as more dependable, self-confident, and intelligent. Greater attraction to extreme profiles was also linked to higher outgroup animosity, suggesting biased social inferences and coordination processes reinforced by contextual factors.