Detecting deception
‘Voodoo’ vs. science in debate on polygraphs

MONTROSE — After grand jurors were able to hear of murder suspect Lionel Lopez’s refusal to take a polygraph, his attorney argued the indictment should be tossed. Polygraphs, public defender Harvey Palefsky said, were not admissible as criminal trial evidence and allowing the grand jury to hear of Lopez’s refusal, plus the results of two other men’s polygraphs, had prejudiced his client.

The local trial court shot down Palefsky’s argument and the Colorado Supreme Court denied his motion without a hearing.

But among polygraph administrators and their critics, the debate is not settled. Doug Williams, a former polygraphist with the Oklahoma City Police, says the polygraph is a “joke” and no more accurate “than the flip of a coin,” while other experts contend it is a valid scientific tool that assists in investigations.

What it does

Developed in the early 20th century as a paper graph system — whose depiction has long been the staple of television crime dramas — the polygraph device of today tends to be computerized.

At the Montrose Police Department, detective and polygraphist Ted Valerio uses a slender, six-inch device that transmits physiological readings to a computer. The results, he said, are numerically scored and can be read exactly the same way, even by another polygraphist. Tampering with results will corrupt the file, rendering it unusable.

The MPD’s device also includes motion sensor pads, a blood pressure cuff and finger cuffs that register sweat. The ink graph of yesterday is now displayed on a computer screen. Valerio also has a Web cam that allows for both audio and video recording of the procedure.

Agent Henry Stoffel, polygraphist for the Montrose office of the Colorado Bureau of Investigation, said the device reads changes in the body that are caused by “fear of detection of deception,” which is monitored through heart- and breathing rates.

“There’s a perception out there that it’s ‘voodoo,’” Stoffel said. “It’s not voodoo. It’s based on scientific study, physiological changes in the body based on the fear of detection of deception.”

The device records breathing, relative blood pressure and perspiration on the surface of the skin.

Don Krapohl, chairman and past president of the American Polygraph Association describes the actual test as: “A carefully crafted protocol that allows people to undergo a physiological recording and from that recording, to be able to produce a fairly high accuracy rate as to the inference of deception or truthfulness.”

But does that really measure deception?

What it shows

“If you’re using a validated protocol and a competent examiner, it allows for inferences of deception up to 90 percent,” Krapohl said. “You can’t just turn it on and have it produce anything meaningful.”

He said a polygraph test measures the subject’s normal patterns and charts reactions to a series of questions applicable to the investigation at hand.

“We look for patterns of reactions across different kinds of questions,” Krapohl said. “From those patterns we can, in a single-issue test, ID you as truthful or deceptive at somewhere around 90 percent.”

“I believe in the system and the way it works,” Valerio said, while showing the equipment to the Daily Press Wednesday. Professional standards prohibit him from giving demo polygraphs. (See related for training and standards).

“It’s standardized and validated. There are certain things found over the years to show someone is attempting deception.”

Williams isn’t so sure, and he challenged Krapohl’s statistics. “The basic premise is there is a reaction that always indicates deception. The problem with that premise is it’s false.”

Williams said he performed between 3,000 and 6,000 polygraphs for the OCPD during his career. He now makes money teaching people how to pass a polygraph.

“About 50 percent of the time, it (a failed polygraph) means you’ve lied. The problem is the other 50 percent of the time, it just means you’re nervous. There is no such thing as a ‘Pinocchio Effect.’”

Williams said the polygraph was not a valid instrument and anyone could be taught how to pass a test. “Because just going in there and telling the truth only works 50 percent of the time and that’s not good enough odds for most people,” he said.

Beating the system

Williams told of his now well known study, conducted with 60 Minutes at the New York office of Popular Photography magazine. He and reporters invited three polygraphists from leading firms to conduct testing on magazine employees they were told were suspected of stealing a camera. Williams said the polygraphists each fingered a different employee as the culprit, with “100 percent certainty,” but in reality, the camera wasn’t missing.

“No camera had been stolen, but three out of three (examiners) called different, innocent people liars,” Williams said.

One of them also had words for Williams, when he submitted to a polygraph about the supposedly missing camera: that he was the most honest person. At the time, the camera was inside his briefcase. The test, he said, was 100 percent wrong, 100 percent of the time.

Krapohl said critics like Williams apparently choose to ignore scientific evidence. Polygraphs can be beaten, he conceded — but then again, so can speed traps.

“Anything that involves human beings can be beaten,” Krapohl said.

He, Valerio and Stoffel all said they can usually tell when someone is trying to trick the system — and Krapohl also said just reading about how to beat a polygraph doesn’t work.

Williams said there’s no evidence that the techniques he teaches can be spotted in a test.

“They just accuse everyone of it (trying to beat it),” he said. “But nobody’s ever caught me and I’ve done it lots and lots of times.”

‘Psychological billy club’

“In a criminal case, if the suspect makes a statement and denies participating in the crime, the polygraph can be used to corroborate what he’s saying or if he’s being deceitful,” Stoffel said. “If it’s showing deceit, obviously, I want to talk with him.”

Valerio said polygraphs alone do not make or break a case. “We look at the totality of the questions. We don’t just take one,” he said. “At no time are we trying to make up things.”

Remember the Lopez case? The judge not only found that a grand jury functions like a preliminary hearing, not a trial, but that the polygraph issue alone did not make or break the indictment — there was ample additional evidence to support it, he said.

Williams said investigators should bear in mind exactly what they are doing when administering a polygraph. “It’s a good psychological billy club and it intimidates people. The polygraph is just a thin excuse to get you into the hands of a skilled interrogator without the benefit of counsel,” he said.

“Yes, it’s useful. So is a Taser gun and a billy club. Water boarding really worked good too.”

Krapohl admits the polygraph has a bad rap, but said there is currently no better method for assessing credibility.

“It’s a two-edged sword. ... Some people have rated accuracy at 100 percent, which is untrue, but we have critics who say it’s not accurate at all, which is also untrue.”

While many courts, including Colorado’s, exclude polygraph evidence from criminal trials, they allow eye-witness testimony, which Krapohl called “horribly, horribly flawed.”

He said other evidence, including psychological evaluations, also had lower accuracy rates than polygraphs, but was still admissible.

“You can cross-examine (witnesses) and make your own evaluation as to credibility,” Williams said, calling the polygraph a crude reaction recorder. “You can’t cross examine on the polygraph. There is no such thing as a lie detector, because there is no reaction that always indicates deception.”

“You can’t cross examine fingerprint evidence. You can’t cross-examine blood evidence,” Valerio countered, adding no one is ever forced to take a criminal polygraph.

“We just want to get to the truth. Our agenda is not to hurt the innocent,” he said. “It’s just another tool we use. By no means do we intend to anything unethical. No one wins at that.”