Norms are the shared rules that regulate behaviour in various social settings. Norms provide a set of guidelines and expectations about what is and is not acceptable or appropriate conduct. They are inculcated and reinforced through an on-going process of socialisation. For sociologists such as Durkheim, all societies are bound together by a normative structure that is essential for their continued existence, and the failure of normative regulation is closely linked to crime and social conflict. The role of norms in inhibiting criminality has been explored from a wide range of criminological perspectives, including Chicago School criminology and social control theories. Criminologists have also examined the ways in which norms at odds with those of mainstream society can support rule-breaking, especially in the context of deviant subcultures.