IT IS BASED ON THE CONCEPT THAT PHYSIOLOGICAL TREMOR OR MICROTREMOR (SUPPRESSED IN STRESS SITUATIONS) CAN BE SHOWN IN THE LABORATORY AS A NORMAL ACCOMPANIMENT TO THE ACTIVITY OF ANY VOLUNTARY MUSCLE, OCCURRING AT THE RATE OF EIGHT TO FOURTEEN CYCLES PER SECOND. THIS PAPER PRESENTS THE RESULTS OF THREE STUDIES BOTH USING AND EVALUATING THE PSYCHOLOGICAL STRESS EVALUATOR AS A LIE AND STRESS DETECTOR. AFTER LAB TESTS, THESE EXPERTS QUESTION THE PHYSIOLOGICAL BASIS UPON WHICH THE PSE WAS CONSTRUCTED SINCE IT IS NOT CERTAIN WHETHER THE LOW FREQUENCY PHYSIOLOGIC TREMORS WHICH IT IS PRESUMED TO DETECT EXIST IN THE SMALL FAST MOVING MUSCLES OF THE LARYNX. TWO EXPERIMENTS INDICATED THAT THE PSE IS NOT SUFFICIENTLY SENSITIVE TO DETECT A LIE WHEN THERE IS LITTLE OR NO JEOPARDY INVOLVED. IN A LABORATORY INDUCED HIGHLY STRESSFUL SITUATION, HOWEVER, THE PSE DOES DIFFERENTIATE BETWEEN STRESS AND NO STRESS AT LEAST 77 PERCENT OF THE TIME. HOWEVER, THESE IDENTIFICATIONS COULD ALSO BE MADE BY SIMPLY LISTENING TO THE RECORDING OF THE SPEAKER. ONLY IN EXPERIMENT THREE WAS IDENTIFICATION OF STRESS USING PSE SIGNIFICANTLY HIGHER THAN CHANCE. IT IS CONCLUDED THAT STUDIES TO DATE ARE NOT SUFFICIENTLY CONCLUSIVE TO RECOMMEND THAT PSE BE USED AS A LIE/STRESS DETECTOR. (AUTHOR ABSTRACT MODIFIED)