title: A general systems taxonomy for psychological defence mechanisms.
abstract: A taxonomy of psychological defence mechanisms based on general systems concepts is proposed. The personality system consists of the subsystems concerned with input, internal processing, and output of information. Psychological defence mechanisms can be classified according to the subsystem whose function is mainly altered. Defence mechanisms primarily altering the input apparatus function through changes in the perceptual process. These include diminution of perception (denial), distortion of the origin of the percepts (projection and introjection), and distortion of subjectively perceived direction of the feelings and thoughts (displacement). Defence mechanisms that primarily alter the functions of the internal processing apparatus include repression, rationalization, intellectualization, isolation, and fantasy/day-dreaming. These mechanisms alter associative and cognitive processes either directly (repression) or indirectly. In reaction formation, there may by a selective distortion to produce an opposite affect. Defence mechanisms that primarily affect the output apparatus include acting out, counterphobic activity, undoing, sublimation, and non-specific activity. Regression and identification are defence mechanisms that affect all the subsystems, input, internal processing and output, more or less uniformly producing effects throughout the personality system. The advantage of this classification scheme is that it relates primarily to directly observable phenomena that can be readily classified. Another advantage is that it may generate researchable neuropsychological hypotheses concerning possible neural substrates of defence mechanisms.
mesh_terms: D003674:Defense Mechanisms; D006801:Humans; D008960:Models, Psychological; D010465:Perception; D010551:Personality