Filtering out Euroskepticism: Media influence and interpersonal communication in an agent-based model of Brexit opinion dynamics

Why do heavily biased media campaigns sometimes fail to achieve expected persuasive effects in electoral contexts? While compelling at the national level, the argument that pro-Leave media bias explains Brexit outcome struggles to account for places such as London and other urban areas, where majorities voted Remain despite exposure to Euroskeptic media. To shed light on this puzzle, this article applies the “filter hypothesis” to examine how interpersonal communication mediates media effects. We extend this framework by incorporating group pressure mechanisms simulating opinion conformity, and building an agent-based model that compares theoretical mechanisms: direct versus mediated media effects, varying conformity levels, and different thresholds for network homogeneity and opinion similarity perception. Our findings show that models incorporating both mediated effects and group pressure mechanisms best replicate observed voting patterns and improve explanatory power.