Sociology of deviance is the area of sociology that studies the violation of social norms or expectations, and researchers studying it will often use social or interpersonal methods of obtaining data. Among the large variety of theories concerning the source and sociology of deviance, class conflict theory, stemming from Karl Marx, is among the foundational and influential theories of the sociology of deviance. Emile Durkheim, on the other hand, based her theory of social deviance on communal cohesion, especially as it relates to pre- and post-industrial societies, and this relates to Kai Erikson's theory of boundary maintenance, in which he asserts that the sociology of deviance is centered around constructing boundaries to keep a community intact. Robert Merton's strain theory is also particularly influential, in which he asserts that deviance is a method of coping with social expectations.
Despite the many theories of the sociology of deviance, most hold that the actions that are considered deviant are relative to each specific society. Similar actions may be given different labels in different time periods and cultures, and even within one culture, social responses can change over time and can be affected by historical events. Theories of social deviance tend to try to develop a model that will explain consistent patterns of deviant behavior throughout different cultures.
Those who research social deviance will often focus on small- and large-scale views of a community. They may interview a small group of individuals personally or perform a survey via many institutions. They may also perform participant observation, in which they spend time in the community they wish to study to gain first-hand knowledge of the social interactions that take place there.
Marx bases all his theory, fundamentally, on class conflict: usually, the more powerful bourgeoisie will pursue its own interests against the proletariat. According to Marx, the criminal justice system, and therefore the laws that define deviant or criminal behavior, exists primarily to protect the upper class and its interests. In addition, a capitalist society will necessarily worsen this division and create deviance because technology will gradually lead to more efficient means of production: those who can keep up with it become economically powerful, while those who cannot are pushed to the edges.
Durkheim held that every society had a collective consciousness of agreed-upon values, and deviance is a normal consequence of a society setting boundaries for itself. In simplistic, pre-industrial societies, social cohesion is greater, but in post-industrial cities, there is more differentiation. As a result, there is more debate regarding deviant behavior, and some behaviors may be considered deviant by some groups while others are not.
Erikson studied the Puritans and the Salem witch trials and developed a theory related to Durkheim's: that a community stays intact by limiting itself to a particular range of activities. Any activities that fall outside this range are condemned as deviant. Each time the community calls individuals to account for this behavior, it is reaffirming those boundaries, but other factors can cause deviant individuals to gain power and shift the boundaries.
Merton's strain theory deals with the different ways people cope with social expectations, and deviant behavior is just part of the different methods. He outlines a major value that society upholds, such as love of money, as well as the ways of achieving it that are labeled as proper. Some, according to Merton, will conform and reach that goal, obtaining monetary success. Innovators will use deviant means of reaching the same goal, whereas ritualists will try to conform, but will not be successful. Rebels are truly deviant in rejecting both the lifestyle and the goal.