By Joel Warner
By Michael Roberts
By Alan Prendergast
By Michael Roberts
By Michael Roberts
By Amber Taufen
By Patricia Calhoun
By William Breathes
The examiner tells you to sit down in an old, creaky chair with high, worn-down armrests. If the chair had straps to secure your legs, it would look like the one they use to fry people at the pen. Even though the examiner has gone over the questions with you for the past hour and a half--giving you the questions before the test--you're shifting in the chair and sweating.
He cinches black sensor-laden straps across your chest and stomach, inflates the blood-pressure cuff around your biceps and clips three clothespin-like sensors onto three fingers of your right hand. He plugs the leads from all these tentacles into a white box that looks like an old floppy-disk drive. That box full of wires and circuits will determine whether you're telling the truth.
Though the actual test will take only twelve minutes, the examiner has taken more than two hours to explain all of its inner workings. Strapped down, you can see him peering at his instruments, but you can't see all the digital squiggles that represent your body functions.
"Stay still and keep your feet flat on the floor," he says. "The test is about to begin.
"Do you understand that I will ask you only the questions we have discussed?"
"Yes," you say, trying to sound nonchalant. But the finger clamps are making you aware of your pulse, and the strap across your chest is making you take shallow breaths.
The examiner pauses for a few seconds between each question. The only sound in the room comes from the whirring of the computer.
"Regarding the charges that you stole the money, do you intend to answer all of my relevant questions truthfully?"
"Do you live in Colorado?"
Easy question. "Yes."
"I want you to deliberately lie on this question," the examiner drones. "Before 1998, did you ever shoplift?"
You hesitate slightly, even though you know you've been instructed to lie about this on purpose. The lie helps establish what the examiner described as a "norm."
"No," you answer.
"Do you remember stealing any money?"
You've been told that the computerized polygraph test can be used as evidence to prove your innocence.
"No," you answer confidently, trying to see how the examiner reacts to your answer out of the corner of your eye. Nothing.
"Stay still, don't move," the examiner gently chides. "This is a deliberate lie. Prior to 1998, did you ever intentionally take something that wasn't yours?"
"Do you remember stealing money in November?"
"This is a deliberate lie. Before the age of 25, did you ever make a serious mistake in judgment?"
"Have you been completely truthful about your work history?"
You have to go through the same set of questions two more times before the ordeal ends.
When it's over, two and a half hours later, the examiner prints out a graph to pinpoint your body's reactions to every question. The computer scores the responses. If it gives you a mark of 85 percent under the heading "Probability Truthful," you're off the hook. The examiner marks the changes in the squiggles, the peaks and valleys--the truths and the lies.
Your combined score on the three tests comes out to be 0.8983. You're telling the truth about the missing money.
At least as far as the polygraph examiner is concerned.
Most Colorado police departments and DA's offices have staff polygraphers even though lie detector tests haven't been admissible in state courts since 1981. Investigators often use polygraph exams to help determine how to proceed with criminal cases. "It doesn't make or break a case if the suspect passes or fails an examination," says Drew Grant, the Arapahoe County district attorney's chief investigator and polygrapher. "We look at how it fits in with the whole picture we have of the case."
The handful of independent polygraph examiners in Colorado who freelance for attorneys and the public flutter around the world of law enforcement like private dicks (in fact, many are also private investigators). Their test results are mostly used by attorneys to help determine whether clients are telling the truth. Sometimes attorneys use positive results to try to convince a district attorney to reconsider pressing charges. "Of course," says Grant, a twenty-year veteran of the DA's office, "we only see the test if the subject passes."
Polygraph examiners don't have to be licensed by the state. In order to be a professional polygrapher, all you need is about $7,000 to buy the newest equipment. You can attend a polygraph school and get a couple hundred hours of instruction and a diploma to hang on your wall. But it's not necessary.
You can join the forty-odd members of the Colorado Association of Polygraph Examiners (CAPE)--but you don't have to. You can pay the $135 annual membership fee and join the American Polygraph Association (APA) and get on the mailing list--but you don't have to do that, either.
That opens the door for some strange types, says David Raskin, the scientist who helped invent computerized polygraph software at the University of Utah back in the Seventies and Eighties. Before Raskin got ahold of the instrument, polygraphs traced a subject's biological responses onto graph paper that was later deciphered by examiners. Raskin thought he could get more accurate results with a digital test. However, dealing with the other people on the project proved to be almost as much of a challenge as computerizing the polygraph.