the application of experimentally derived principles of learning to the treatment of psychological disorders. The concept derives primarily from work of the Russian psychologist Ivan Pavlov, who published extensively in the 1920s and 1930s on the application of conditioning techniques and theories to abnormal behaviour. Behaviour-therapy techniques differ from psychiatric methods, particularly psychoanalysis, in that they are predominately symptom (behaviour) oriented and show little or no concern for unconscious processes, achieving new insight, or effecting fundamental personality change.

Behaviour therapy was popularized by the U.S. psychologist B.F. Skinner (Skinner, B.F.), who worked with mental patients in a Massachusetts state hospital. From his work in animal learning, Skinner found that the establishment and extinction (elimination) of responses can be determined by the way reinforcers, or rewards, are given. The pattern of reward-giving, both in time and frequency, is known as a “schedule of reinforcement.” The gradual change in behaviour in approximation of the desired result is known as “shaping.” More recent developments in behaviour therapy emphasize the adaptive nature of cognitive processes.

One of the most prominent behaviour techniques, variously known as systematic desensitization, reciprocal inhibition, extinction, or counter-conditioning, has its experimental basis in work done with animals in the 1950s by psychologists Joseph Wolpe and Arnold Lazarus. In one such experiment, cats were conditioned with electric shock to refuse to eat in a confined space. Their conditioned fear was overcome by feeding them in remotely similar situations and gradually increasing the similarity until all signs of anxiety had disappeared. When the technique, known as desensitization, is applied to human problems, patients may be asked either to imagine anxiety-producing situations or to deal with actual feared objects or situations. The construction of hierarchies of fears is perhaps the most important part of the procedure; the patient's verbalized responses are the primary source of information, although the therapist may also rely on such other sources as diagnostic tests or interviews of family or friends of the patient. Often relaxation training is employed in the presence of the anxiety-producing stimuli. The theoretical question of whether these procedures involve reduction in the habit strength of anxiety responses or establishment of alternative, adaptive responses to the same stimuli remains unresolved.

Much evidence has been collected to demonstrate the effectiveness of structured learning and behaviour therapy in groups. Assertiveness training is the broad term for a structured group situation that facilitates the acquisition of emotionally expressive behaviour. Such training is based on the behavioral concept that once the appropriate overt expressions of emotions are learned, practiced, and reinforced, the correlated subjective feelings will be felt.

In 1975, the U.S. psychologist Robert P. Liberman introduced assertion or personal effectiveness training as a fundamental component of the clinical services offered by community health centres.

A number of other behavioral techniques have been used in therapy. aversion therapy causes a patient to reduce or avoid an undesirable behaviour pattern by conditioning him to associate the behaviour with an undesirable stimulus. The chief stimuli used in the therapy are electrical and chemical. In the electrical therapy, the patient is given a lightly painful shock whenever the undesirable behaviour is aroused; this method has been used in the treatment of sexual deviations. In the chemical therapy, the patient is given a drug that produces unpleasant effects, such as nausea, when combined with the undesirable behaviour; this method has been common in the treatment of alcoholism, the therapeutic drug and the alcohol together causing the nausea. Another approach reinforces desired responses with praise, food, or some other reward.

Behaviour-therapy techniques have been applied with some success to such disturbances as enuresis (bed-wetting), tics, phobias, stuttering, obsessive-compulsive behaviour, drug addiction, neurotic behaviours of “normal” persons, and some psychotic conditions. It has also been used in training the mentally retarded.

In addition, behavioral self-control has received great academic attention, particularly learning to control the functions of the autonomic nervous system (e.g., heart rate, blood pressure, and intestinal contractions) by methods such as biofeedback (q.v.). The theory and therapy of self-control represents a significant humanistic development within the area of behaviour modification, by enhancing personal responsibility. See also behaviourism; conditioning.