In addition to sociological and biological explanations of deviant behavior, there are also psychological explanations. Three of the major psychological theories of deviance include psychoanalytic theory, cognitive development theory, and learning theory. There are several fundamental assumptions that all psychological theories on deviance have in common. First, the individual is the primary unit of analysis in psychological theories of deviance. That is, individual human beings are solely responsible for their criminal or deviant acts. Second, an individual's personality is the major motivational element that derives behavior within individuals. Third, criminals and deviants are seen as suffering from personality deficiencies. Thus, crimes result from abnormal, dysfunctional, or inappropriate mental processes within the personality of the individual. Finally, these defective or abnormal mental processes could be caused from a variety of things, including a diseased mind, inappropriate learning, improper conditioning, and the absence of appropriate role models or the strong presence of inappropriate role models. Read more about these theories and how they explain deviant behavior.