Sociological theories of crime have been categorized into three broad groups: strain theories, subcultural deviance theories, and control theories. Strain theories are characterized by the premise that crime and delinquency result when socially approved ends cannot be achieved through conventional channels, and illegal activities are chosen as alternative means of obtaining the desired ends. Subcultural deviance theories postulate that some subgroups in society hold values contrary to the values of the dominant society and that some of these subgroups condone and even encourage criminal and delinquent activities. Control theories argue that involvement in delinquency and crime results when an individual's bond to conventional society is weakened or destroyed. Psychological theories emphasize the characteristics of the person as the primary factor in crime causation. Such theories include the psychoanalytic theory, the moral development theory, social learning theory, and a biologically rooted conditioning theory. Each or a combination of these theories explains some but not all deviant behaviors. 22 references.