Subjects consisted of 40 males recruited from group counseling sessions at the Veteran's Center in Pittsburgh. Ages ranged from 22 to 43, and years of education ranged from 9 to 21. Physiological recordings were made with a Stoelting Polyscribe Model 22770. The paper describes the laboratory mock crime experiment which randomly assigned the subjects to four treatment conditions: one-half were assigned to guilt conditions and, with guilty and innocent conditions, subjects were assigned to be given either the positive control or the control test first. Guilty subjects were instructed to remove a ring, without being caught, from a desk drawer in the polygraph firm's waiting room and conceal it on their person while taking the polygraph examination. Results indicated that the positive control test was an inferior method for detecting deception techniques as compared to the control question test. The weakness of the positive control test appears to be that it does not provide a set of stimuli that elicit differential physiological reactivity between truthful and deceptive subjects. These results seriously question the widespread field use of the test. Tables and 14 references.