Anna Keuchenius, Petter Törnberg, Justus Uitermark Sociological Science May 11, 2026 10.15195/v13.a22 Abstract The influential “echo chamber” hypothesis suggests that social media drive polarization through a mutual reinforcement between isolation and radicalization. The existence of such echo chambers has been a central focus of academic debate, with competing studies finding ostensibly contradictory empirical evidence. This article identifies a fundamental methodological limitation of these em