Role theory (or social role theory) is a concept in sociology and in social psychology that considers most of everyday activity to be the acting-out of socially defined categories (e.g., mother, manager, teacher). Each role is a set of rights, duties, expectations, norms, and behaviors that a person has to face and fulfill. The model is based on the observation that people behave in a predictable way, and that an individual's behavior is context specific, based on social position and other factors. Research conducted on role theory mainly centers around the concepts of consensus, role conflict, role taking, and conformity.
Although the word role has existed in European languages for centuries, as a sociological concept, the term has only been around since the 1920s and 1930s. It became more prominent in sociological discourse through the theoretical works of George Herbert Mead, Jacob L. Moreno, Talcott Parsons, Ralph Linton, and Georg Simmel. Two of Mead's concepts—the mind and the self—are the precursors to role theory.