Defensive style and performance on objective personality measures

Two studies on the relations between various styles of defense and the power or validity of self-reports on objective personality questionnaires. The power of individual items on the Rotter Internal-External Locus of Control scale to discriminate between subjects defined as internals or externals by a median-cut procedure using the total score was not affected by the presence Or absence of a projective defensive style. However, the presence of repressive tendencies did appear to restrict item power. Prediction from two achievement scales taken from Gough's California Psychological Inventory was not influenced by level of repression, was affected somewhat adversely by a projective style, and was most clearly contaminated by a rationalizing defense. It was proposed that the differential effects of defensive styles upon the validity of personality tests depended upon the convergence or divergence of the cognitive operations involved in the type of defense and in the type of personality measure.