“Glynn County Police Like Voice Stress Lie Detector; Others Not So Sure

The Associated Press reports on Glynn County, Georgia’s use of and professed belief in “Computer Voice Stress Analysis” (CVSA). Excerpt:

BRUNSWICK, Ga. — Glynn County police have become true believers in a new sort of lie detector that analyzes stress in a suspect’s voice, but other police departments are not convinced.

The Computer Voice Stress Analyzer helped snare William David Tatro, who was convicted earlier this month for killing his wife and burying her in a garden in his front yard.

Tatro initially told police two different versions of what happened to his wife, Yukie Tatro.

Glynn police Sgt. Chip Anderson said Tatro first told them he “didn’t know where his wife was, that she (had) driven away in her car.” He then agreed to answer questions about her disappearance on the voice stress test.

“Mr. Tatro changed his story after we confronted him with results of his voice stress test, which showed that he had been deceptive in his statements about her disappearance. That’s when he told us that he killed her accidentally,” Anderson said.

Yukie Tatro’s decomposed body was found Oct. 5, 2000. William David Tatro is awaiting sentencing.

Jurors never heard any testimony about the voice stress test, but Anderson said it was “an important tool” leading investigators to Yukie Tatro’s body and her killer.

“It bolstered our feeling that (William Tatro) knew more about her disappearance than he was saying, and it showed us that we were going in the right direction with our investigation,” Anderson said.

About 1,200 law enforcement agencies nationwide use the voice stress test, including 38 in Georgia and 124 in Florida.

The instrument uses a special computer program to detect, measure and analyze the micro-frequency modulations in a person’s voice. The frequency changes can be used to determine lying or truthfulness, police said.

But neither voice stress analysis, nor the more traditional polygraph tests are admissible in court as evidence in Georgia, Florida or federal courts, authorities said.

Glynn County public defender Timothy Barton said the analyzer shouldn’t be used as evidence because, like a polygraph, it hasn’t been proved scientifically accurate.

“It’s a crude tool, but it’s a tool. I’ve got no problem with it as an investigative tool, as long as the police don’t use it to trick people,” Barton said. “We want the truth as much as the police do. If it helps get at the truth then I’m for it.”

While Glynn County public defender Timothy Barton has no problem with the use of CVSA as an “investigative tool, as long as the police don’t use it to trick people,” that is precisely how CVSA (like polygraphy) is used–as an interrogation tactic to trick suspects into believing that they have been caught in a lie, and to convince them that it is in their best interest to confess. Neither polygraphy nor CVSA has any scientific basis, and no reliance should be placed on the outcome of such “tests.”

“Voice Analyser Pyramid Points to Truth”

Louise Dickson reports on the first use of Computerized Voice Stress Analysis (CVSA) by Canadian police in this puff piece published in the Victoria Times Colonist. Excerpt:

“Did you actually see Ruth shoot Billy?”

“Yes,” the suspect replied.

“Did you shoot Billy?”


But the image on the computer screen told another story. In this Florida case, a picture was worth 25 years.

The Florida investigator was using a computerized voice stress analyser to detect deception. Saanich police have the first analyser in use in Canada.

“It’s a very accurate instrument,” said Saanich police Sgt. Don Wiebe as he played the taped interrogation in the Florida case. “If done accurately and correctly by the operator, it will be 100 per cent effective in verifying truth.”

The Florida investigator, trying to get to the bottom of a a drug shooting, hooked up his suspect to the voice stress analyser. After a series of direct questions, it became apparent that both Ruth and her boyfriend had shot Billy.

Wiebe said that using the $16,000 analyser is as easy as hooking a microphone to a lapel. The microphone directs the sound into the software of the computer. The tool, used by 1,103 law enforcement agencies in the U.S., is portable and less intrusive than a polygraph test.

The machine works by measuring the FM frequency in the voice, Wiebe explained.

“Voices line up in two modulations, AM and FM. When you are speaking, your AM frequency rides on top of your FM frequency. If you are under considerable stress, the FM in your voice diminishes,” said Wiebe.

When someone gives a perfectly truthful answer, the voice stress analyser projects an image on the computer screen of a pyramid with diagonal lines. When someone lies, the diagonal lines diminish and plateau. The pyramid shape becomes more of a block.

Like polygraphy, CVSA, peddled by the “National Institute of Truth Verification,” is a pseudoscientific fraud. In the early 20th century, uncritical journalism of the kind we see here helped to delude the general public into believing in the myth of the polygraph. Now, in the early 21st century, the same process continues with respect to CVSA.

“Police Using Voice Stress Analysis to Detect Lies”

Associated Press writer Michael Rubinkam reports on the pseudoscience of voice stress analysis. Excerpt:

PHILADELPHIA (AP) — Police want to know if a suspect is lying, but the polygraph test comes back inconclusive.

What’s an exasperated interrogator to do?

Increasingly, law enforcement agencies are using a technology that measures “voice stress” — small frequency modulations in the human voice that supposedly occur whenever someone is lying.

Some police officials swear by the Computer Voice Stress Analyzer — a laptop computer, software and microphone package that promises to catch deception.

Proponents call it just as reliable as a polygraph but more portable, less intrusive and easier to use. Additionally, law enforcement in some states can surreptitiously record a suspect’s voice, then run the tape through the analyzer.

The industry hopes to get a boost from the new federal aviation safety law, enacted in the wake of the Sept. 11 attacks. A provision of the law calls for the use of “voice stress analysis, biometrics or other technologies” to prevent terrorists from boarding airplanes.

But how well does it work? Studies suggest that voice stress analysis is no better than chance at detecting deception. It is banned in several states and, like the polygraph, it is not admissible in any court of law.

“There is no scientific evidence to validate it,” said Victor Cestaro, a retired biological psychologist who conducted research on voice stress for the U.S. Department of Defense Polygraph Institute.

Nevertheless, the National Institute for Truth Verification, the West Palm Beach, Fla., company that makes the market-leading Computer Voice Stress Analyzer, says it has sold the devices to 1,100 law enforcement agencies across the country.

The cost: more than $11,000 for the analyzer and a six-day training course.

Another company, Diogenes, sells a similar device called the Lantern for about $4,700, plus $950 for one week of training.

Voice stress analysis, like polygraphy, is junk science. See the CVSA forum of the AntiPolygraph.org message board for discussion of this pseudoscience.

“Lying Technology: Now in Morgan County [Missouri]: New-Age Lie Detector Measures Micro Tremors”

Marsha Paxson gullibly reports on Computerized Voice Stress Analysis (CVSA) for the Lake Sun Leader of Camdenton, Missouri. Excerpt:

MORGAN COUNTY – The same type of lie detection machine used to test former President Bill Clinton when he claimed not to have had sex with Monica Lewinksy is now being used in the arsenal against crime in Morgan County and Laurie.

Morgan County Sheriff’s Department Investigator Greg Martin said he and three Laurie police officers are now certified to use a Computer Voice Stress Analyzer.

“It is a specially-designed program that works on a Toshiba laptop computer,” Martin said. “Each machine has one key that is required for operation. No other key can open it and only trained eyes can decipher what the test markings mean.”

A small microphone with a clip is attached to the suspect’s clothing while the tester asks questions.

“While a standard lie detector measures physiological changes when a subject gives an answer, the CVSA registers micro tremors in the human voice,” Martin said. “We can determine deception when there is a lack of FM frequency in the voice.”

CVSA, like polygraphy, has not been proven by peer-reviewed research to work better than chance under field conditions. While confessions elicited from naive and gullible suspects may be useful, it is irresponsible for law enforcement officers to place any reliance on the results of these pseudoscientific “tests.”

“Vocal Stress Can Betray You in a Lie”

Julie Novak uncritically reports on Computerized Voice Stress Analysis in this single-source Narragansett Times article. Excerpt:

NARRAGANSETT – If you want to tell a lie, don’t tell it to Narragansett Police Lt. Vincent Carlone.

The department’s head of detectives has learned how to analyze vocal stress, and with the assistance of a laptop computer he’s prepared to play “Truth or Consequences” with any suspect who’s brought in for questioning.

Last Friday, Carlone completed an Advanced Examiners Course at the National Institute for Truth Verification in West Palm Beach, Florida. Carlone was among 120 participants from all over the country, and the only one from Rhode Island, in the week-long course.

The program trains only members of the law enforcement community in how to use the Computer Voice Stress Analyzer, an investigative tool that assesses the amount of stress in a subject’s voice to indicate deception.

“I’m currently the only certified examiner in the department, but we have plans to train more personnel,” Carlone said. “This really is a wonderful tool.”

The Stress Analyzer requires no wires be attached to a subject being questioned. A multi-functional laptop computer, the analyzer requires only a microphone plugged into the system. As the subject speaks, the computer displays each voice pattern in the form of a graph, numbers it, and saves each chart to a specific file.

“The graphs are activated by the discreet changes in the human voice,” Carlone explained as he demonstrated the equipment Tuesday.

Micro tremors, he said, are tiny frequency modulations in the human voice. When someone is lying, the automatic, or involuntary nervous system, causes an inaudible increase in the micro tremor’s frequency. Once the Stress Analyzer detects, measures, and displays changes in the voice frequency, they are processed graphically and display a picture of the voice patterns.

“An angular and steep pattern is good, but a horizontal or box-like pattern indicates stress or deception,” Carlone said.

In the advanced course, Carlone learned to use new and different patterns of questioning, called formats. The Stress Analyzer has built-in questioning formats, but also allows an investigator the freedom to create his or her own line of questioning.

“You use different types of formats depending on what the investigation is,” Carlone said. “I can tailor my questions so they are applicable to the situation.

“Sometimes you have to be graphic so a subject understands what you’re getting at. If I asked a subject if they sexually assaulted someone, they might not understand what that means so I would have to ask about specific details.”

The Stress Analyzer is not restricted to yes or no answers and is able to accurately analyze recordings of unstructured conversations.

Wary of giving away any “trade secrets,” Carlone said that using a variety of questions allows investigators to make comparisons and evaluate specific lines of questioning applicable to an investigation.

First introduced in 1988, the original Stress Analyzer was an analog computer. It has progressed into its current digitized form and is effective in all investigative situations such as homicide, sex crimes, robbery, white collar crimes, as well as pre-employment examinations for background investigators.

“This machine has really made the difference for us in serious investigations,” Carlone said.

Cases of sexual assault and breaking and entering and larceny in Narragansett have been cleared up easily because of the Stress Analyzer, Carlone said.

“What I like best about it is clearing innocent people. You can have a group of people pointing the finger at someone, but if they come out fine on the test then you can clear them. It’s nice to be able to clear someone from blame.”

It is an unsettling thought that the head of detectives of a municipal police department would believe that suspects can be cleared (or not cleared) based on a pseudoscientific voice stress analysis “test.” Narragansett Times reporter Julie Novak’s unquestioning parroting of Detective Carlone’s claims is evocative of the uncritical early 20th century reporting that helped to entrench polygraph “testing” in popular American mythology.

“Cops Seek Voice of Truth”

Bloomsburg, Pennsylvania Press Enterprise writer Michael Reich reports on Computerized Voice Stress Analysis (CVSA). Excerpt:

HAZLETON — When someone lies to police here, a “truth verification” machine might be able to sense the fib by recording changes in a person’s voice.

Hazleton Police Chief Edward Harry says the machine has led to confessions in 75 percent of the roughly 500 cases it has been used in here over the years. The national average is 35-40 percent, he said.

“That just shows how many times that we’ve got confessions and made arrests on cases that we wouldn’t have been able to do that,” the chief said.

But some have criticized the computer voice stress analyzer (CVSA) for inaccuracy. A 1996 Department of Defense review found it had a success rate of only 49.8 percent on 109 test subjects, some of whom took part in a mock crime that involved the theft of $100, according to the Web site www.voicestress.com.

Like polygraph lie detector tests, results from a CVSA are inadmissible as evidence in court. But more and more departments are turning to the machine, Harry said.

“Other departments are starting to see that this really works,” he said.

CVSA, like polygraphy, is a pseudoscientific fraud and only “works” to the extent that it elicits confessions from naive and gullible suspects.

“Police Use of Voice Stress Analysis Generates Controversy”

Margie Wylie reports for the Newhouse News Service in a well-researched article on CVSA. Excerpt:

Police departments across the country are buying the controversial Computer Voice Stress Analyzer, which its manufacturer claims can tell when a person is lying merely by the sound of his voice. When a suspect speaks, a computer program “listens” for minute vocal shifts that, in theory, indicate stress.

The technology’s critics, citing government and university research, say the CVSA is little more than an electronic Ouija board with accuracy rates to match. At best, they say, voice stress analysis scares suspects into confessions; at worst, it can incriminate the innocent.

CVSA results aren’t admissible in most courts, under the same Supreme Court decisions that generally bar polygraph evidence.

Even so, police officers love it. Cheaper and faster than the polygraph, the CVSA can be operated with a few days’ training and without the need to “wire up” a suspect. It can also be used in the field, covertly, and on tape recordings, according to the National Institute for Truth Verification of West Palm Beach, Fla., its manufacturer.

Between 1999 and 2000, NITV added 100 new customers. So far in 2001, NITV officials say nearly 300 police departments have bought at least one CVSA. Some have bought several, and nearly all “have put their polygraph on the shelf,” said David Hughes, a retired police captain and executive director of the company.

Originating from a Cold War military project, voice stress analysis was first commercialized in the early 1970s.

NITV, founded in 1986, has a virtual lock on the law-enforcement market,according to both the company and its critics. It has sold its $10,000 CVSA to more than 1,100 police departments and trained more than 4,200 CVSA operators at about $1,300 each, Hughes said.

The company’s Web site is replete with testimonials and success stories. One Alabama police department is said to have solved a murder case 14 years cold by re-interviewing the main suspect with the CVSA. The suspect had previously taken four polygraphs given by three different examiners, all inconclusive. Confronted with three failed voice stress tests, he broke down and confessed.

Researchers counter that nothing in 30 years of studies proves that voice stress analysis works, either generally or in the specific case of the CVSA.

“Voice stress analysis is a fraud. It has zero validity,” said David T. Lykken, a psychology professor emeritus at the University of Minnesota in Minneapolis and author of the book “A Tremor in the Blood: Uses and Abuses of the Lie Detector.”

For discussion of CVSA, see the CVSA forum on the AntiPolygraph.org message board.

“Honest, It’s the Truth”

Moira Gunn writes on “Computer Voice Stress Analysis” (CVSA) for SiliconValley.com. Excerpt:

Here’s what I call scary technology. Ever hear of a `voice stress analyzer`? It’s almost exactly what it says it is. It’s a technology that purports to measure a selection of inaudible characteristics of the human voice. Of course, it’s the `analyzer` part that’s scary. Even if we know the values of these so-called characteristics, once known, how do we know what they mean?

Mercury News staffer Sean Webby reports that the FBI refuses to use these devices and the U. S. Department of Defense Polygraph Institute gives them a less than 50 percent accuracy rating.

So, the burning questions for me are: Who would use them? And why?

According to the Web site for the National Institute for Truth Verification (NITV), an organization that manufactures this equipment, its product is used by some 1,000 police departments, two dozen district attorneys and prosecutors, and nearly 40 correctional facilities. Add to this the California Highway Patrol and you’ve got yourself a mighty array of law enforcement agencies.

“Bay Area Officers Turn to Voice Analyzer”

Sean Webby of the San Jose Mercury News reports. Excerpt:

Bay Area police departments are snatching up one of the latest technological tools in crime-solving — a computerized voice analyzer that’s supposed to determine when the bad guy is telling a lie, just by the sound of his voice.

But critics say this $10,000 device doesn’t work; it only intimidates suspects into confessions.

Police departments in San Jose, San Francisco, Menlo Park, Mountain View and Redwood City are among about 1,000 agencies that use “voice stress analyzers.” The California Highway Patrol uses the machine when hiring officers.

Law enforcement agencies have only one place to buy the controversial devices and train their officers at $1,300 per student — the National Institute for Truth Verification, a private company in West Palm Beach, Fla.

Yet many law enforcement agencies refuse to use the analyzers, including the FBI and both the San Mateo County and Santa Clara County sheriff’s departments.

Several police chiefs and other senior investigators in departments who bought the voice analyzers said privately they doubted that the device measured the truth very well. But all said it did what they had bought it to do — elicit confessions from suspects who are convinced the machines work.

“It’s a marketing scam,” said Sgt. Gary Hoss, who is the chief polygrapher for the San Mateo County Sheriff’s Department. “It’s fast and it’s cheap and it doesn’t work, and that’s the bottom line.”

Hoss and others predict these voice analyzers will put innocent people in jail and expose police departments who use them to massive lawsuits.

Yet NITV says its product is more powerful at detecting a criminal’s deception than polygraph tests.

“It can’t get much more accurate,” said David Hughes, the company’s director and a retired captain from the West Palm Beach, Fla., police department. NITV reports that its analyzer has about a 98 percent accuracy rate.

Merrillville, Indiana P.D. Buys Into CVSA

In an article entitled, “New equipment will give police edge on liars,” staff writer Erin Howard of the northwest Indiana Times reports. Excerpt:

MERRILLVILLE — Lie detection is one of many methods police use to solve criminal cases, and the Merrillville Police Department will soon have the latest lie detector technology at its disposal.

The ancient polygraph machine, which measures a person’s heart rate and breathing changes to determine if the person is lying, is being replaced by many departments with a Computer Voice Stress Analyzer. The analyzer detects, measures and displays changes in the voice.

Unlike the polygraph, the voice analyzer requires no wires, instead it uses a microphone plugged into a laptop computer to analyze the subject’s voice responses, said Capt. David Hughes from the National Institute for Truth Verification in Palm Beach, Fla. As the subject speaks, the computer displays each voice pattern, numbers it and saves each chart to a file, he said.

“We’ve never had any type of lie detector or anything like that previously,” Merrillville Police Chief John Shelhart said. “So hopefully this is going to help our officers’ ability to interview suspects and ascertain conclusions on their truthfulness.”

The Town Council approved the purchase of the lie detection technology Tuesday. The $13,000 purchase price includes comprehensive training in use of the technology for four police officers.

While the Computer Voice Stress Analyzer “detects, measures and displays changes in the voice,” these changes have no demonstrable correlation to whether the speaker is telling the truth or not. The article goes on to state that over 1,000 police departments in the United States, including 81 in the state of Indiana, have purchased these devices.