Behavioral modification, as championed by B.F. Skinner (1904-1990) in the 1950s, relies on the principals of operant conditioning. It employs carefully designed rewards (or positive reinforcement) to encourage desirable behavior. Likewise, removal of key rewards reduces incentive for undesirable behavior. Alternatively, punishment can be used to decrease frequency of undesirable behavior. Punishment is used less frequently than positive reinforcement, however, because it tends to elicit negative reactions. In sum, behavioral modification changes behavior by manipulating the rewards and punishments that motivate people to perform the behavior.

Such techniques are used in child rearing and animal training as well as the treatment of emotionally disturbed children and individuals with mental retardation. Oper-ant conditioning techniques are also widely used in situations requiring some degree of social control, for example in prisons, schools, and even the workplace. They are less frequently used in individual therapy, as such techniques are most useful for people who lack internal motivation to change their behavior. For the most part, people seeking out psychotherapy on their own do so because they are already motivated to change.