Polygraph and the CVSA (Computerized Voice Stress Analyzer)

The following is courtesy the American Polygraph Association Web Site The following CVSA research was compiled by Donald Krapohl.

Various investigative techniques for detecting deception have appeared in the past 80 years. Some were developed by scientists and researchers, like reaction time tests, the polygraph, and brain wave methods. Others were proffered by manufacturers without the help of researchers, such as the B&W lie detector and the various voice stress devices.

The most recent method being heralded as the new lie detector is the Computer Voice Stress Analyzer (CVSA). What separates the CVSA from previous voice stress methods is that the display is on a computer screen, versus on paper. There are no validated algorithms or scoring systems, or sophisticated analytical methods. These shortcomings have not prevented the manufacturer from making remarkable claims regarding the efficacy of its product.

Computerized Voice Stress Analyzer

Computerized Polygraph

But, are they true? Those of us in the detection of deception profession would like to believe it because switching to this new device would allow us to better serve our clients and agencies in a shorter time. Before we accept the self-endorsements of the manufacturer, it is best that we first look at what scientists have to say.

Below is a list of university-grade research studies that have investigated voice stress as a deception detection approach. Some studies looked at the CVSA device in particular, while others investigated whether voice stress analysis, in general, could be used to detect stress or deception. Copies of these studies can be obtained at many university libraries.

Brenner, M., Branscomb, H., & Schwartz, G. E. (1979). Psychological stress
evaluator: Two tests of a vocal measure. Psychophysiology, 16(4), 351-357.
Conclusion: “Validity of the analysis for practical lie detection is

Computerized Voice Stress Analyzer

Computerized Voice Stress Analyzer (CVSA)

Cestaro, V.L. (1995). A Comparison Between Decision Accuracy Rates
Obtained Using the Polygraph Instrument and the Computer Voice Stress
Analyzer (CVSA) in the Absence of Jeopardy. (DoDPI95-R-0002). Fort
McClellan, AL: Department of Defense Polygraph Institute.
Conclusion: Accuracy was not significantly greater than a chance for the

DoDPI Research Division Staff, Meyerhoff, J.L., Saviolakis, G.A., Koenig
M.L., & Yourick, D.L. (In press). Physiological and Biochemical Measures of
Stress Compared to Voice Stress Analysis Using the Computer Voice Stress
Analyzer (CVSA). (DoDPI01-R-0001). Department of Defense Polygraph

Conclusion: Direct test of the CVSA against medical markers for stress (blood
pressure, plasma ACTH, salivary cortisol) found that CVSA examiners could
not detect known stress. This project was a collaborative effort with Walter
Reed Army Institute of Research.

Fuller, B.F. (1984). Reliability and validity of an interval measure of vocal
stress. Psychological Medicine, 14(1), 159-166
Conclusion: Validity of voice stress measures was poor.

Janniro, M. J., & Cestaro, V. L. (1996). Effectiveness of Detection of
Deception Examinations Using the Computer Voice Stress Analyzer.

(DoDPI95-P-0016). Fort McClellan, AL : Department of Defense Polygraph

DTIC AD Number A318986.
Conclusion: Chance-level detection of deception using the CVSA as a voice
stress devise.

Hollien, H., Geison, L., & Hicks, J. W., Jr. (1987). Voice stress analysis and lie
detection. Journal of Forensic Sciences, 32(2), 405-418.
Conclusions: Chance-level detection of stress. Chance-level detection of lies.
Horvath, F. S. (1978). An experimental comparison of the psychological stress
evaluator and the galvanic skin response in the detection of deception. Journal of
Applied Psychology, 63(3), 338-344.
Conclusion: Chance-level detection of deception.

Horvath, F. S. (1979). Effect of different motivational instructions on detection
of deception with the psychological stress evaluator and the galvanic skin
response. Journal of Applied Psychology, 64(3, June), 323-330.
Conclusion: Voice stress did not detect deception greater than chance.
Kubis, J. F. (1973). Comparison of Voice Analysis and Polygraph As Lie
Detection Procedures. (Technical Report No. LWL-CR-03B70, Contract
DAAD05-72-C-0217). Aberdeen Proving Ground, MD: U.S. Army Land
Warfare Laboratory.
Conclusion: Chance-level detection of deception for voice analysis.

Lynch, B. E., & Henry, D. R. (1979). A validity study of the psychological
stress evaluator. Canadian Journal of Behavioural Science, 11(1), 89-94.
Conclusion: Chance level detection of stress using the voice.
O’Hair, D., Cody, M. J., & Behnke, R. R. (1985). Communication
apprehension and vocal stress as indices of deception. The Western Journal of
Speech Communication, 49, 286-300.
Conclusions: Only one subgroup showed a detection rate significantly better
than chance, and it did so by the thinnest of margins. The use of questionable
statistical methods in this study suggests the modest positive findings would
not be replicated in other research. See the next citation.

O’Hair, D., Cody, M. J., Wang, S., & Chao, E. Y. (1990). Vocal stress and
deception detection among Chinese. Communication Quarterly, 38(2, Spring),
Conclusion: Partial replication of above study. Vocal scores were not related to
Suzuki, A., Watanabe, S., Takeno, Y., Kosugi, T., & Kasuya, T. (1973).
Possibility of detecting deception by voice analysis. Reports of the National
Research Institute of Police Science, 26(1, February), 62-66.
Conclusion: Voice measures were not reliable or useful.
Timm, H. W. (1983). The efficacy of the psychological stress evaluator in
detecting deception. Journal of Police Science and Administration, 11(1), 62-
Conclusion: Chance-level detection of deception
Waln, R. F., & Downey, R. G. (1987). Voice stress analysis: Use of telephone
recordings. Journal of Business and Psychology, 1(4), 379-389.
Conclusions: Voice stress methodology did not show sufficient reliability to
warrant its use as a selection procedure for employment.

Please remember, a CVSA or a “Voice Stress Lie detector” is NOT a Polygraph Instrument. Nor is it a POLYGRAPH Exam! Know the difference.