Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


The purpose of this study was to examine the effect of various instructional sets on the MMPI performance of prisoners. Specifically, an attempt was made to examine whether any significant biases existed in the scales and ratios used to measure the prisoner's attitudinal set concerning the MMPI. Ninety-six subjects were selected from the U.S. Camp and Penitentiary in Lompoc, California. The subjects were randomly assigned to three groups of 32 subjects each. One group was requested to take the MMPI under instructions to malinger psychopathology. Another group was instructed to take the MMPI under instructions to deny or conceal any psychological problems. The third group was administered the MMPI under standard instructions so as to serve as a control group. The results indicated that subjects were able to feign maladjustment on the MMPI when instructed to do so. At the same time, the validity indicators were effective in detecting the malingering subjects. Under instructions to feign hyper-adjustment, the subjects were considerably less successful in manipulating the clinical scales. Likewise the validity measures were not uniformly effective in detecting attempts to fake good. Appropriate cutoff points were devised for each of the validity indicators which successfully produced significantly different distribution between the experimental and control group subjects. The results were discussed in terms of various forensic and legal issues concerning the use of the MMPI with prisoners.