There is no shortage of studies on the various PSE® instruments and their accuracy. Exclusive of articles, testimony and other reports, there are more than 60 formal independent studies of various applications, which are clearly favorable to the PSE® system. While many of these were accomplished in universities, medical centers, and mental health centers, some were directly associated with criminal activity.
- Heisse, J “Is the Micro-Muscle Tremor Usable?- The Micro Muscle Tremor in the Voice” U.S. House Subcommittee of the Committee on Government Operations, 1974. Heisse analyzed 91 known conclusion criminal responses utilizing voice stress analysis and determined the “audio stress analysis seems to valid in detecting changes in various psycho physiological parameters so that a trained examiner utilizing standard techniques can evaluate these changes and thus utilize the instrument in truth and deception” (available from the Library of Congress)
- Lippold, O., J. Vuco, R. “The Rhythmical Activity of Groups of Muscle Units in the Voluntary contraction of Muscle”. The Journal of Physiology, August, 1957. Lippold, Redfearn and Vuco begin exploring the correlation between muscle activity and stress (available from the Library of Congress).
- Lippold, O. “Oscillations in the Stretch Reflex Arc and the Origin of the Rhythmical l8-12 C/S Component of the Physiological Tremor” The Journal of Physiology, February, 1970 Lippold first discovers the physiological tremor in the human voice in the 8-12 hz range. (available from the Library of Congress).
- Chapman, J. Criminal Justice Department, Corning Community College, NY. “The Psychological Stress Evaluator as a Tool for Eliciting Confessions”, 1989. Chapman selected 211 criminal responses at random from 2109 known conclusion responses where Voice Stress Analysis was used to test suspects. Professor Chapman’s study confirmed that Voice Stress Analysis was accurate when utilized as a truth device and produced a confession rate of 94% of the responses where deception was indicated.
- Smith, G.A. “Voice Analysis for Measurement of Anxiety.” British Journal of Medical Psychology. 1977. The author concludes that Voice Stress Analysis is a valid measure of anxiety. (Available from the Library of Congress)
- Borgen, L.A. Goodman, L.I. Parke-Davis Research Laboratories, Ann Arbor, MI “Voice Stress Analysis of Anxiolytic Drug Effects” . Results of the study indicated that Voice Stress Analysis of the verbal responses correlated well with the other physiological responses to acute stress (available from the Library of Congress)
- Inbar, GF, Eden, G. Department of Engineering Technion, Israel Institute of Technology, Haifa, Israel. “Psychological Stress Evaluators: EMG Correlation with the Voice Tremor” published in Biology of Cybernetics, 1976. Inbar and Eden were able to independently verify the existence of the 8-14 hertz “micro-tremor’ and trace its origins to the central nervous system (available from the Library of Congress).
- Brenner, M. “Stage Fright and Steven’s Law”. Department of Psychology, Ohio State University, presented at the convention of the Eastern Psychological Association, April 1974. Brenner, utilizing a voice stress analyzer (PSE), established that the frequency of vocal stress increased as a function of audience size (available from the Library of Congress)
- Brockway, B.F. University of Colorado School of Nursing, Denver Colorado, “ Situational Stress and Temporal Changes in Self and Vocal Measurements”. Presented to the annual meeting of the American Association for the Advancement of Science”, February 1977. Brockway’s study reports that Voice Stress Analysis does depict predictable and self-reported anxiety. (available from the Library of Congress)
- Ruiz, Legros & Guell, 1990. Voice Stress Analysis to predict the psychological or physical state of a speaker. Published in Aviation, Space and Enviromental Medicine, 1990. Ruiz et al. reports that their “research suggests that psychological stress may be detected as acoustic modifications in the fundamental frequency of a speakers voice” and “that the fundamental frequency of the vocal signal is slowly modulated (8-14hz) during speech in an emotionally neutral situation. In situations demanding increased mental or psychomotor activity, the 8-14 hz modulation then decreases as the striated muscles surrounding the vocal cords contract in response to the arousal, thus limiting the natural trembling”. (available from the Library of Congress)
- Wiggins, S.L., McCranie, M.L. and Bailey, P. Department of Psychiatry, Medical College of Georgia, Augusta, Georgia. “Assessment of Voice Stress in Children”. Published in the Journal of Nervous Disorders. 1975 The authors concluded that “audio stress can be detected with a PSE in a psychiatric patients during the course of therapy and that the PSEcould serve as a useful tool for this purpose” (available from Library of Congress).
- Heisse, J. Dr.; 1976 Carnahan House Conference on Crime Counter-measures, May 5 1976, University of Kentucky; Dr. Heisse, a practicing otolaryngologist, had conducted a study to validate and to establish the reliability of the Psychological Stress Evaluator. The study concluded: 1. “Audio Stress Analysis utilizing the PSE (Psychological Stress Evaluator) seems to be valid in detecting various psychophysiologic parameters in truth and deceptions so that a properly trained examiner, utilizing standard techniques, can evaluate these changes and thus utilize the instrument (PSE) in truth and deception”. (2) “the compliance between evaluators and the known results with 258 evaluation replies, is 96.12 percent.”