||Social movements respond to demography in two distinct ways. First, the people who comprise a social movement often have distinctive demographic features. In addition, the demographic profile of a society can shape the opportunities and motivations for social movement mobilization. Societies with very large youth cohorts tend to have more radical, and sometimes violent, movements; older societies tend to have more peaceful and moderate ones. Whether a society is rapidly urbanizing can determine the location and effectiveness of popular revolts. Finally, the particular age, religious, and ethnic cleavages in society, and how the proportion and characteristics of people in different identity groups changes over time, creates conflicts but also opportunities to resolve them. These principles are illustrated with the examples of the US civil rights and Tea Party movements, and the 2010–11 Arab revolts.