Labelling theory was developed by Howard Becker and is based on the simple idea that deviance is not a characteristic of an act, but instead a label that is placed on an act. The famous quotation being "deviance is behaviour that we so label"; it is the reaction to behaviour that determines whether or not it is deviant, not the act itself. This of course can then go on to have other consequences, such as what individuals do with the labels that are placed on them and how society reacts to those who are labelled deviant. As such this theory is fundamental to interactionist theories of crime.