{"ID":2849072,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2510.24354","arxiv_id":"2510.24354","title":"Rewarding Engagement and Personalization in Popularity-Based Rankings Amplifies Extremism and Polarization","abstract":"Despite extensive research, the mechanisms through which online platforms shape extremism and polarization remain poorly understood. We identify and test a mechanism, grounded in empirical evidence, that explains how ranking algorithms can amplify both phenomena. This mechanism is based on well-documented assumptions: (i) users exhibit position bias and tend to prefer items displayed higher in the ranking, (ii) users prefer like-minded content, (iii) users with more extreme views are more likely to engage actively, and (iv) ranking algorithms are popularity-based, assigning higher positions to items that attract more clicks. Under these conditions, when platforms additionally reward \\emph{active} engagement and implement \\emph{personalized} rankings, users are inevitably driven toward more extremist and polarized news consumption. We formalize this mechanism in a dynamical model, which we evaluate by means of simulations and interactive experiments with hundreds of human participants, where the rankings are updated dynamically in response to user activity.","short_abstract":"Despite extensive research, the mechanisms through which online platforms shape extremism and polarization remain poorly understood. We identify and test a mechanism, grounded in empirical evidence, that explains how ranking algorithms can amplify both phenomena. This mechanism is based on well-documented assumptions:...","url_abs":"https://arxiv.org/abs/2510.24354","url_pdf":"https://arxiv.org/pdf/2510.24354v2","authors":"[\"Jacopo D'Ignazi\",\"Emma Fraxanet Morales\",\"Andreas Kaltenbrunner\",\"Gaël Le Mens\",\"Fabrizio Germano\",\"Vicenç Gómez\"]","published":"2025-10-28T12:19:41Z","proceeding":"cs.SI","tasks":"[\"cs.SI\",\"cs.CY\"]","methods":"[]","has_code":false}