A Collective Field Experiment Disentangling Participation in Online Political Discussions

Online discussions are often dominated by a small group of active users, while the majorityremain silent. To investigate what differentiates active from silent users, whether participation inequality can be mitigated, and the downstream effects on discourse dynamics, weconducted a collective field experiment on Reddit. We recruited 520 U.S. participants andrandomly assigned them to six private communities. Participants discussed 20 political issues over four weeks and completed weekly surveys. Results show that frequent commenterswere highly interested in politics and posted more when they perceived the community aspolarized and toxic. In contrast, silent users were more likely to break their silence whenthey perceived the discussion to be respectful and constructive. Over time, positive socialfeedback reinforced commenting. Incentivizing commenting reduced participation inequality, whereas emphasizing moderation norms unexpectedly increased toxicity. Although corediscussion roles persisted, the interventions seem to have activated different user groups—offering insights into ways of fostering more equitable online discourse.