New Voice in Lie Detection Some Police Say Voice Stress Test Is Faster, Cheaper Than Polygraphs

Article excerpt

Byline: Robert Sanchez Daily Herald Staff Writer

The detectives on television make it look so easy.

A blink.

A hand gesture.

A bead of sweat on the forehead.

That's all they need to know someone is lying.

Of course, experience tells us that catching anyone in a real life fib is lot more difficult.

Or is it?

A technique called voice stress analysis claims to make lie detecting as simple as listening to someone talk. Using a computer laptop, special software and a microphone, an interviewer can determine if someone is telling the truth.

Local police departments say the technique is so simple and inexpensive they are pushing to get Illinois law changed so they can use it during investigations.

"You could use it to question people and eliminate them as suspects in a crime," said Gurnee police Detective Jack Metcalf, who learned about voice stress during a recent training session attended by investigators from Cook, Lake and McHenry counties.

"The sooner you eliminate people as suspects, the happier they are and the sooner crimes get solved," he said.

Jeff Pavletic, a chief deputy state's attorney for Lake County, agrees voice stress could become "an extremely valuable tool" for law enforcement if state law is changed or modified.

"Right now it's a grass-roots effort," Pavletic said. "It's one of those things where we are going to patiently approach this issue with the lawmakers in Springfield."

But polygraph groups are committed to persuading state politicians to leave the law alone.

Elmhurst Police Chief John Milner, who is president of the Illinois Police Chiefs Association, said he has been getting repeated requests for the association to endorse voice stress. But Milner said there isn't any scientific evidence that proves it works.

"We would love to support voice stress if it works," Milner said. "But from the studies I have seen, it's not any more accurate than flipping a coin."

A recent study by the Department of Defense concluded there was "no credible evidence to validate voice analysis as an effective instrument for determining deception."

Harry Reed, president of the Illinois Polygraph Association, said, "If someone can prove to me through valid scientific research that voice stress works, I will buy one of the devices. But the fact is it doesn't work."

Results from lie detection tests are not admissible in court as evidence in Illinois. But state law does allow lie detection devices to investigate crimes.

The requirement is that the test must simultaneously measure respiration, skin response, blood pressure and pulse to determine if someone is being untruthful.

The only device that does that is the polygraph test.

Unlike polygraph, voice stress analysis works by detecting small frequency modulations in the human voice, called "micro tremors," involuntarily created by the nervous system when someone lies.

Micro tremors can't be heard by the human ear.

But the West Palm Beach, Fla.-based National Institute for Truth Verification claims to produce a computer software program that can detect micro tremors.

"If our product didn't work, we wouldn't be in business," said David Hughes, the company's executive director. …