Understandings of social movements have changed dramatically from purportedly scientific but in fact heavily normative accounts that depicted mass action as anomic and irrational. Reification reached its peak in North American social science during the 1950s and 1960s when scholars made a sharp disciplinary and conceptual distinction between conventional and unconventional politics. William Gamson aptly notes, “Political science claimed ‘normal’ prescribed politics as its bailiwick, leaving social movements to the social psychologist whose intellectual tools prepare him to better understand the irrational.”

Since the 1970s, social movement scholarship has taken several turns. First, the resource mobilization approach challenged assumptions about the irrational character of social movements by demonstrating the significance of their organizations, networks, and resources. Next, scholars argued that social movements emerge when political opportunities exist and sought to link the emergence and growth of social movements to changes in the political environment. Scholars then emphasized the cultural dimensions of protest by exploring how social movements framed their demands and drew upon earlier repertoires of contention.

Social movements are collective actions that challenge authorities to effect change. Although their goals differ, many of their cultural repertoires are similar. They combine ideological appeals with symbolic acts and discourses to identify and interpret what they deem social injustice. Movements call on people to take personal risks even when the odds are against them. They crystallize deeply held identities and beliefs and simultaneously express popular anger, frustration, pride, and fear. They rouse people to action by providing them with a sense of efficacy, common purpose, and the possibility of a better, if idealized, world. They appeal to moral values to purify what is commonly seen as the dirty world of politics. Social movements are less constrained than parties in the ideologies they promote, the constituencies they represent, the demands they make, and the tactics and strategies they deploy.

Social movements are simultaneously expressive and instrumental, and voluntaristic and organized. Their emotionally charged activity entails purposeful interactions with the state. David Meyer comments, “Unlike pigeons in Skinner's boxes, people who make movements are moral and instrumental actors, if not always narrowly ‘rational calculators.’” Movements often affirm established moral codes even as they question and subvert them.