Comparison Between Decision Accuracy Rates Obtained Using the PolygraphInstrument and the Computer Voice Stress Analyzer (CVSA) in the Absence of Jeopardy

摘要

This two-experiment study was designed to (1) validate the underlying electronictheory of operation of the Computer Voice Stress Analyzer (CVSA), and (2) examine the decision accuracy and agreement rates using the traditional polygraph instrument and the CVSA. The CVSA input/output was evaluated using simulation signals from lab test generators. Forty-two subjects took psychophysiological detection of deception (PDD) examinations with the polygraph and CVSA instruments, within the context of Peak of Tension (POT) tests using numbers between 3 and 8. Half of the subjects were tested with the polygraph instrument, then the CVSA instrument. The remaining half were tested using the instruments in the opposite order. PDD and CVSA based POT tests were blind-evaluated by four examiners for each instrument. The frequencies of accurate determinations made using each instrument were compared using proportionality tests. The lab simulations established that the CVSA performs electrically according to the manufacturer's theory of operation. The CVSA and associated processes were less accurate than the polygraph and PDD processes tested in similar circumstances (38.7% vs. 62.5%). Interrater reliability, assessed using a multiple rater Kappa test, showed agreement among all blind evaluators within each instrument category was significantly better than chance (p < .05). These data indicate there may be a systematic and predictable relationship between voice patterns and stress related to deception.