Would I lie to you? Herts Ad reporter gets grilled in Herts Police’s polygraph test


Taylor - Credit: Archant

“Fight, flight or freeze,” explains polygraph examiner, Tim Benson, “is how physiologists talk about the body’s response to stress.

“If you’re walking down an alleyway late at night, for example, and you hear a bang somewhere in the distance, even momentarily, your body is going to be experiencing some level of stress.”

According to Tim, your body’s reaction to stress can be summed up into one of three categories: fight, flight or freeze.

He says: “When something like that happens, changes are taking place in your body that you can’t control: heart rate, sweat rate – these happen automatically. When you tell a lie, your body responds in a similar way.”

Tim is one of two polygraph examiners now working for Herts Police, which is one of only two forces in the UK using polygraph machines - better known as lie detectors.

Herts Police has carried out a polygraph test 117 times since its introduction in the summer (118 after my visit). Sex offenders, as well as those accused of downloading indecent images of children, are asked if they would mind participating in a polygraph examination.

The purpose is to minimise risk. Those applying to be removed from the sex offenders register, for example, will be asked to take a polygraph test as part of that procedure.

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Tim says: “We don’t force them to [take the test]. A lot of people say yes, which is good for us because it helps us build trust.”

If somebody refuses to take a test, it is not held against them, although Tim says: “We would be concerned if they said no – we’d be curious as to why that was.”

The tone of the examinations, Tim tells me, is informal. He says: “We spend a lot of time explaining to people how it works and some of the science behind it. A lot of people turn up and say, ‘this is like being on Jeremy Kyle’. Or people say they’re going to beat it – normally by the end of it they’re not very sceptical.”

I was sceptical. If Jeremy Kyle furiously waved around polygraph results like they were on fire, why were the police taking them so seriously? So when, in a small room in a secret location, Tim said, “when you lie, we should see some responses on the screen”, I saw it as a challenge.

The test we were going to do was the so-called ‘acquaintance test’. Tim asked me to think of a number between three and eight (I chose six) and write it in the middle of a piece of paper.

Starting at the top of the page, Tim then wrote three, four, five, and under my six, the numbers seven and eight.

So in a vertical line in the middle of the page were the numbers three to eight.

Tim then told me to answer truthfully, and asked whether I had written the number three, four, five and so on.

He explained: “That’s what we’re going to do on the test, except on the test I want you to say no to every question, including number six.

“When we get to number six, you’re going to lie to me. You’re going to say ‘no’ to every single question.”

Then we set about plugging me in to the lie detector: two of my fingers were strapped up in metal plates to measure my ‘galvanic skin response’ - how much I perspired.

Another device measured my heart rate and I had two ‘pneumographs’ wrapped around me, one on my chest (for my breathing), one on my stomach (for the gastric fibs, I presumed). I also had a blood-pressure monitor on one arm and I sat on a pad which measured my movement.

Tim switched on the machine and began asking questions. “Regarding the number that you wrote,” he said, “did you write the number three?”

“No.” This is going to be a cinch, I thought.

“Did you write number four?”

“No,” I said, feeling the lie approaching.

“Did you write the number five?”

“No.” I could feel my pulse rise under the weight of the impending lie.

“Did you write the number six?”

“No,” I said and heard my heart throb in my ears. I felt the blood-pressure monitor tighten, too.

Tim asked about seven and eight, but it was too late. I’d given the game away. I’d blown it - the results of my polygraph proved as much.

The graph showed a steady incline of my heart rate and a spike in my galvanic skin response as Tim asked about six, showing beyond doubt where I had lied.

My scepticism dissolved. If my body had such a response to an inconsequential lie, then how must those people who have a lot riding on the strength of their answers react?

Polygraphs are likely to be rolled out to more forces around the country and Tim, who had three months of training in order to use it, says he has “no doubts” about the method’s efficacy and is “very confident” in Herts Constabulary’s ability to minimise risk by using this technology.

Maybe Jeremy Kyle has been onto something all along.