Abstract
The purpose of this study was to evaluate two commonly used voice stress analyzers: NITV’s computer voice stress analyzer (CVSA) and Nemesysco’s layered voice analysis (LVA) system. In both cases, a speech database was used, which contained materials recorded (1) in the laboratory, while highly controlled deceptive and shock induced stress levels were systematically varied and (2) during a field procedure. Subjects were 24 males and females (age range 18–63 years) drawn from a population representative of the United States. All held strong views on an issue and were required to make sharply derogatory statements about it. The systems were then evaluated in a double blind study using two sets of examiners: (1) two UF scientists trained/certified by the manufacturers and (2) either three experienced CVSA operators or two LVA instructors provided by the manufacturer(s). The results for both devices showed that the “true positive” (or hit) rates ranged from chance to somewhat higher levels—50% to 65%—for all conditions/types of materials (stressed‐unstressed, truth, or deception). However, the false positive rate was just as high—often higher. Sensitivity statistics demonstrated that these systems operated at about chance levels. [Work supported by Counterintelligence Field Agency, DoD.]
Published Version
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