When attitudes don’t matter–until they do

Why do some behaviours rapidly spread across society, while others fade despite widespread support? Theories of attitudes and social influence often provide competing explanations. We present an agent-based model that integrates three basic intuitions from social sciences: that behaviour is affected by individual dispositions, by social influence, and by one’s past behaviour. Simulating the joint dynamics of these three mechanisms shows that even small attitudinal preferences can determine society-level outcomes, and that all three mechanisms are required for this process to unfold. Our results reconceptualize the attitude-behaviour gap in dynamic terms and problematize the view of attitudes and conformity pressures as competing forces. The results provide a new look at the unexpected rise of behaviours that are disapproved by the majority, such as populist voting, climate denialism, and resistance to vaccination.