Is the Truth Worth $500,000?

Dec. 13, 2007— -- Hook someone up to a lie detector. Ask personal questions. Watch the person squirm.

That's the premise of the new Fox TV reality show, "The Moment of Truth," which some polygraph experts have criticized.

Contestants are asked a series of personal -- and potentially embarrassing -- questions while connected to a polygraph machine. Answer honestly, the premise goes, and you win money.

But an association of polygraph examiners is already questioning the accuracy of the show, which airs next month. The American Polygraph Association, a trade association of polygraph examiners that promotes the use of the machines, calls the show an irresponsible misuse of lie detectors.

"This is a wholesale abuse of a technology that has appropriate use in national security and community safety," said Don Krapohl, the association's chairman.

In the show, contestants undergo a pretape polygraph test, taken by a certified polygraph expert, of about 75 questions. They are not told the results of the test.

A few days later, they are asked 21 of those questions on camera and in front of an audience. The more answers that match what the lie detector says is true, the more money they win, up to $500,000.

Friends and family, who are in the audience, have a button they can hit to stop the contestant from answering.

Similar programs are being produced in 23 other countries, according to Fox, not always without controversy. A similar show has been a hit in Colombia but was briefly taken off the air earlier this year after a woman reportedly admitted on air that she had hired a hitman to kill her husband.

The questions in the U.S. version tend toward the confidential. Some samples: "Is there a part of your husband's body that repulses you?" "Do you really care about the starving children in Africa?" "Are you sexually attracted to one of your wife's friends?" "Do you like your mother-in-law?" "Do you think you'll be with your husband five years from now?"

Answering the questions, sometimes in front of the very people who may be hurt by the answers, is all part of the novelty and intentional controversy of the show, says Fox. "What deep, dark secret will someone divulge for hundreds of thousands of dollars?" the network's promotional materials ask.

But Krapohl of the American Polygraph Association said polygraph machines are unable to measure some of the kinds of questions that appear to be asked on the show, such as ones that measure attitudes and inclinations.

Polygraphs "test on past behavior, not on what's going on in your head," he said. The former head of the FBI's polygraph unit, who was not familiar with the show, said the machines also cannot accurately measure a person's beliefs, opinions or expectations.

A Fox spokesman, Michael Roach, declined to comment on the criticism. Mike Darnell, the station's president of alternative entertainment, told the Los Angeles Times that early tapings show that contestants do lie during the show but don't challenge the lie detector.

"It's like a reality soap," he told the paper. "Every one of us thinks about these things and has these thoughts, but we never have to say a word. But this show reads people's minds. If they want the money, they have to be honest."

Polygraphs work by tracking how a person's body, through measurements such as blood pressure and pulse, responds to a series of questions. Though they accurately measure stress, the National Academy of Sciences has warned that the tests don't necessarily show that a person is lying. A 2002 study warned that polygraphs are "intrinsically susceptible to producing erroneous results."

Polygraphs are widely used by law enforcement agencies, who stand by their usefulness as investigative tools, though the results of the tests are generally inadmissible in court.

The Polygraph Association, which promotes the use of the tests, says studies have shown they are about 90 percent accurate in field tests, when used to ask about specific events in the past. They are less accurate when used in laboratory simulations. The National Academy of Sciences put it this way: "Specific-incident polygraph tests can discriminate lying from truth telling at rates well above chance, though well below perfection."

The tests are far less accurate when used in employment screening, according to the Academy, and federal courts have warned that their accuracy is still subject to debate.

Kendall Shull, the former head of the FBI's polygraph program, said that for questions to be reliable, they should be focused on past actions; questions that are too general or too broad could produce inaccurate results, he said.

The questions shouldn't focus on a person's intentions. "You cannot ask questions that ask for a person's beliefs, opinions or expectations," he said.

"You can't ask if your spouse loves you. You can't ask if they intend to divorce you," he said. "But you can ask if they've visited an attorney."

Contestants sign an agreement not to challenge the results of the polygraph test and Darnell told the Times that contestants tend not to dispute the accuracy of the test when caught in a lie.

James Blascovich, a University of California at Santa Barbara psychology professor who has done research on polygraph tests, suggested that the tests are useful because people believe they are accurate. "Because people believe, they might confess," he said.