Success-Driven User Activity Contributes to Online Polarization

Online social networks are often seen as a breeding ground of political polarization.This study introduces an additional explanation why, attributing polarization to success-driven user activity.Using an agentbased model, we demonstrate that polarization intensifies when users become more active after experiencing rewarding interactions on the platform.We compare a basic version of Axelrod's cultural dissemination model, which lacks success-driven activity, with an extended version that does include it.Our analyses replicate key findings from the literature and show that success-driven activity consistently enhances polarization, even in scenarios like complete networks or minimal network clustering, where Axelrod's model typically predicts uniformity to be unavoidable.Success-driven activity triggers a self-reinforcing "rich-get-richer" dynamic, where success leads to more activity and vice versa, resulting in a highly skewed success distribution.A few highly successful users dominate discussions, causing local convergence and fragmenting the population into distinct groups.This polarization arises in a model without biased media, polarized elites, algorithmic echo chambers, or users intentionally distancing themselves from others.We discuss the implications for designing online social networks that do not exacerbate polarization and for creating digital twins of online platforms for regulatory and analytical purposes.