Why the psychology of collective action requires qualitative transformation as well as quantitative change

The argument of this paper is that social psychological models of collective action do not (and cannot) adequately explain social change and collective action through models based on shared variance between variables. Over and above the questions of why and how collective action and social change occur, such models do not adequately address the question of when they occur: at what point on a measure of perceived illegitimacy - or any other predictor - does a person decide that enough is enough, and at what point do shared grievances transform into mass protest? Instead, it is argued that the transition from inaction to action at the level of both the individual and the group is better conceptualised as a qualitative transformation. A key agenda for the social psychology of collective action should therefore be to conceptualise the link between quantitative variation in predictors of action and the actual emergence of action.