Micro-foundation of opinion dynamics: Rich consequences of the weighted-median mechanism

The key to obtaining a mechanistic and reliable understanding of complex public opinion formation processes is identify the main mechanism governing interpersonal influence. Researchers have long been exploring simple yet predictive mathematical models dynamics. Although most are based on assumption that individuals update their opinions by averaging others' opinions, researchers might need rethink this universally adopted micro-foundation. deceivingly weighted-averaging features non-negligible unrealistic implication, which brings unnecessary difficulties in seeking proper balance between model complexity power. In paper, we fundamentally resolve problem proposing weighted-median as new micro-foundation Such an inconspicuous change from median leads rich consequences. mechanism, derived cognitive dissonance theory psychology, well supported online experiment data. It also broadens applicability dynamics multiple-choice issues with ordered discrete options, e.g., political elections. Moreover, comparative studies show predicts various real-world patterns evolution while some widely studied averaging-based fail to, including how group structure affects likelihood reaching consensus extreme located social networks.