Chery Sabol reports for the Daily Inter Lake of Kalispell, Montana uncritically reports on “Computerized Voice Stress Analysis” (CVSA). Excerpt:
It sounds metaphysical.
Without ever laying eyes on you, detective Lance Norman of the [Flathead County] sheriff’s department believes he can tell if you are lying.
Spoken answers reveal to him ‹ directly, on the telephone or on audio tape, in any language, from any subject young or old, even if the speaker has no larynx ‹ whether someone is being deceptive.
Norman and deputy Jeanne Landis are certified in the use of a Computer Voice Stress Analyzer ‹ a device that exceeds the accuracy of old polygraph tests, he said.
“CVSA, on a bad day, is about 93 percent” accurate, he said. Polygraphs run around 80 percent, he said.
It’s not metaphysics; it’s science, Norman said.
The voice-stress test measures an inaudible part of human vocalization.
People speak in AM and FM, Norman explained. Amplified modulation is what we hear. Frequency modulation isn’t audible, but it’s the key to detecting deception, he said.
Stress caused by lying is measurable in FM levels. It is specific to lying, Norman said. While a person might answer questions about an event that was stressful, it is the irrespressible stress of a lie that reliably measures on Norman’s gauges.
“As stress increases in the human body, FM decreases in voice tones,” he said. “If we as humans could hear FM, no one would ever get away with lying in the world.”
That’s how the voice-stress test outperforms polygraphs, Norman said. There are ways to control pulse rates, respiration and other reactions recorded by a polygraph.
There is no way to control FM levels.
“A skilled pathological liar can not cheat CVSA. It can’t be done,” Norman said.
Despite Detective Lance Norman’s enthusiasm for it, CVSA, like polygraphy, has not been proven through peer-reviewed scientific research to differentiate between truth and deception at better-than-chance levels. While techniques for “cheating the CVSA” by altering one’s voice may not be available, the behavioral countermeasures described in Chapter 4 of The Lie Behind the Lie Detector should be helpful for anyone facing a pseudoscientific CVSA “test” in the context of an application for employment. As with the polygraph, anyone suspected of a crime should refuse to submit to any CVSA interrogation and get a lawyer.