Closed-Mindedness Prevails and Cascades in Online Political Spaces (WP-26-03)
Michalis Mamakos, William Brady, Steven Franconeri, Galen Bodenhausen, and Eli Finkel
The unwillingness to consider alternative viewpoints hinders the integration of differing perspectives required to resolve contentious problems. Here, the authors conducted the first large-scale behavioral study of closed-mindedness, examining its prevalence and the reactions it receives in online political spaces. They first developed a text classifier of closed-mindedness by fine-tuning a large language model, then applied it to Reddit comments. Closed-mindedness was significantly more prevalent in political than nonpolitical communities. Within political communities, closed-mindedness was more common among comments expressing partisan views, and it predicted social disapproval more strongly when these views misaligned with the community’s lean. Closed-minded comments were likelier to elicit replies, and those replies were especially likely to be closed-minded, suggesting a cascade of closed-minded exchanges that hinder constructive discourse. These findings underscore closed-mindedness as a core and self-reinforcing feature of online political discourse, thereby compromising the active consideration of diverse perspectives critical for healthy democratic functioning.