IQ and Defense Mechanisms Assessed with the TAT

Abstract

Abstract. The concept of defense mechanism has a long history in psychoanalysis and clinical psychopathology. The function of defenses has been modified over the years, from a counter-force against instincts to the protection of self-esteem. To understand the role of defenses in pathological and normal development, a coding method to use with Thematic Apperception Test (TAT) stories – the Defense Mechanism Manual ( Cramer, 1991a ) – has been developed and validated. Three broad defenses – Denial, Projection, and Identification – may be coded with this method. The article presents examples of TAT stories that have been coded for defense use. These show how defense use changes after a period of psychotherapy, and how defenses change with age. Evidence for reliability and validity is provided, both from correlational and experimental studies. The remainder of the paper focuses on the relation between the use of defense mechanisms and intelligence. Research has shown that the two ego functions of defense and IQ are not correlated in childhood and adolescence, but are correlated in adulthood defenses and IQ. Importantly, IQ serves as a moderator for the effect of defense use on variables such as psychiatric symptom change, level of Ego Development, and Big Five personality traits.