Marcel Kittel takes lie detector test to try and prove he's not doping

Marcel Kittel, the German sprinter who exploded to prominence when he won the opening stage of this year’s Tour de France, has undergone a lie detector test in an attempt to ‘prove’ that he is not doping.

Germany’s Bild magazine challenged 20 German Tour riders, from teams such as the former Gerolsteiner, Milram, and T-Mobile squads, to submit to polygraph testing to demonstrate they were not doping.

Only Kittel stepped up.

Marcel Kittel after winning Stage 1 of the 2013 Tour of Oman (picture courtesy Tour of Oman)

The 25-year-old has insisted he is part of a new, clean generation of racers. Toward the end of last year, he took to Twitter to lambast those who defended Lance Armstrong.

"I feel SICK when I read that Contador, Sanchez & Indurain still support Armstrong. How does someone want to be credible by saying that?!" he tweeted.

"It makes it all worse. They should play their false game somewhere else."

A polygraph is actually a collection of instruments that measure physiological indicators such as blood pressure, pulse, respiration, and skin conductivity. A questioner asks neutral questions such as the subject's name, and irrelevant questions they are likely to lie about such as "Have you ever told a lie?" to establish baseline readings, then asks a mixture of relevant and control questions.

Kittel was put through the polygraph process by forensic psychologist Holger Leutz who concluded that Kittel was speaking the truth.

“The things we have monitored during the interview were very evenly measured,” said Leutz. “That is a sign of credibility. Kittel makes us believe in a pure generation of cyclists. I dare say in response to what the detector indicates that Marcel Kittel has never used doping and is a clean athlete.”

“I have nothing to hide, so I decided to take the test,” Kittel told Bild. “I stand for clean sport, and the test proves it.”

Polygraph reliability

Or does it? Unfortunately, the history of the polygraph is strewn with failure. In his book, The Secret Race, Tyler Hamilton wrote:

I learned that if you’re vague enough, you don’t have to lie. I said things like “I’ve always been a hard worker,” and “I’ve been at the top consistently for ten years,” and “I’ve tested clean dozens of times,” and so on. I learned that if you repeat something often enough, you begin to believe it. I even took a lie-detector test to help prove my innocence, and passed. (Though, just before taking it, we Googled a few tips for beating the test. Clenching your buttocks, I remember, was one.)

In more serious cases, double-agent Aldrich Ames passed two polygraph tests while spying for the Soviet Union, and serial killer Gary Ridgway passed a polygraph in 1984, only confessing almost 20 years later when confronted with DNA evidence.

As a result, polygraph tests are inadmissible as evidence in criminal cases in most jurisdictions, though they may still be used during investigations to fool or intimidate suspects into confessing.

Germany is one of the countries that absolutely forbids the use of polygraph evidence in criminal trials.

Experience in lying seems to be the biggest factor in beating a polygraph, as Hamilton implies. In 1978, Richard Helms, former director of the CIA, said: “Americans are not very good at [fooling the polygraph], because we are raised to tell the truth and when we lie it is easy to tell we are lying. But we find a lot of Europeans and Asiatics can handle that polygraph without a blip, and you know they are lying and you have evidence that they are lying."