Doug Williams is a former Oklahoma city cop, and one of the most vocal critics of the polygraph test in the U.S. He says he's administered thousands of tests, including some for the FBI and the US Secret Service. For the past three decades, he's been teaching people techniques to beat the test through his books and DVD's. But the U.S. federal government says what he's doing is illegal, and next week he'll be facing federal charges in court. Here, he explains why he thinks polygraph tests are a complete sham - and what he makes of the charges he's facing.

If I wanted to join the Royal Canadian Mounted Police right now, I would have to undergo a polygraph test. What advice do you give me?

Never work for any agency that employs this insidious Orwellian instrument of torture because that is nothing but a foreshadowing of all the trauma that you will endure at their hand.

You've administered thousands of these tests over the years. Why are you so sure that the test doesn't work?

Because in order for a polygraph examination to be accurate and reliable as a lie detector, then you must have a reaction that always indicates deception. My problem with a polygraph is that it's based on a faulty scientific premise. There is no such thing as "lying reaction." What the polygraph operators are claiming, is that every time your breathing becomes erratic, your blood pressure increases, and the sweat activity on your hand increases, that this reaction indicates deception. The problem is that the scientific evidence all proves that while this reaction may be induced by the stress of lying, about fifty percent of the time the problem lies in the fact that simple nervousness, embarrassment, even the tone of the examiner's voice, can elicit a reaction that would brand you as a liar. So there is no such thing as a Pinocchio response, therefore there is no such thing as a lie detector.

Back to the R.C.M.P. test then, what do I need to do physically in order to make sure that that test is not used against me?

The polygraph is a comparison of questions, [like] did you tell the truth on your job application, are you withholding any information, have you committed a serious crime? Those are called relevant questions. They then intersperse control questions: have you ever stolen anything, have you ever lied to anyone that trusted you, have you ever lied to an authority to keep getting in trouble? If you have this reaction on a relevant question and you don't have it on a control question, they say that you have lied. So all I do is teach people how to relax. I have a relaxation script and tell them to picture themselves lying on the beach when they answer the relevant questions to avoid showing a reaction. Then on the control questions, I tell them to think of something frightening, like falling off of a building or whatever, thus providing the polygraph examiner with a perfect, classic, textbook truthful chart.

But defenders of the polygraph test say that the test is still better than any other existing technology.

Why don't you think there is some value in the test even if it doesn't perform perfectly?

Well I could just as easily make the same argument for a magic 8 ball or flipping a coin because they have the same degree of accuracy. In other words, I could say "Okay, even though it's not perfect, when I flip this coin, if it comes up heads, you're lying."

Doug Williams - From Cop to Crusader (Doug Williams)

You're saying the polygraph test is not scientific. Why is it then that they continue to be used by government agencies and law enforcement?

Because the polygraph operators have a vested interest in perpetuating this myth that they can detect deception with it, and they are convincing those in positions of power to continue to employ them because it's a multibillion dollar industry. If you want to figure out why something continues, just follow the money.

Let me ask you about your experience using the machine Doug, because you've had decades of experience with it. When you were administering tests for the police, you also conducted tests on behalf of private companies who are looking to test their employees. How did people react to those tests?

With great fear and trepidation. When you come in for a job, your goal is to get that job. You want to put your best foot forward. But when you walk into my office for a polygraph test to get that job, I've changed your goal. Your goal is to pass the polygraph, and in order to pass the polygraph, you have got to answer completely truthful and you will divulge things to me that you have never told another living soul.

Did you see people who lost their jobs as a result of these tests that you gave?

Tons of them. I was quite a smart alec back then. We'd go through two, three, or four hours of interrogation for an applicant. Then at the end I would say "Okay, I've got some good news and some bad news. The good news is, you passed the polygraph test, you told me the complete truth. But the bad news is, you aint't going to get the job because of all the crap you told me.

Tell me about one person whose story stuck with you.

I remember one case still that stands in my mind. It was a woman who had been accused of arson. She was the sister in-law of the city manager, and the city manager was putting a lot of pressure to go easy on her and so, I did quite the opposite. I interrogated her very intensely, broke her down emotionally and mentally, and got a confession out of her. She began sobbing and then basically went almost limp.

So what did it do to you personally and psychologically to have been playing that role?

It destroyed me and my spirit in so many ways. Physically, my blood pressure would go to extremes, I was drinking heavily. If you've got any conscience at all, it has to take a toll on you. If it doesn't, then you just gotta consider yourself a really calloused psychopath or sociopath. That's the only thing it could be.

You're facing serious charges and there could be jail time involved. The charges include obstruction of justice. How are you going to prove that you're innocent of those charges?

I do not know. My attorney is very concerned, I'm very concerned. They're trying to put on so many restrictions on what the judge will allow into evidence. They're trying to keep it to where I can't even debate the validity and reliability of the polygraph, and I can't bring in any of my previous good deeds. It sounds like the deck is stacked against me. So I'm already out $25,000 for my attorney and I don't know how to craft a defense against something that I did not then, and do not now, think was a crime. All I did was teach someone how to relax when they're going through an interrogation. If they're successful, they will have they will have imprisoned me, for upwards of 100 years, for protesting the use of the polygraph and doing it the loudest and the longest.

You've spent a long time thinking about this, do you think there ever will be a machine that can detect lies?

Your wife at 3am.