Sunday, March 02, 2008

The moment of "truth"

Much ado has been made recently over a woman on the Fox program Moment of Truth admitting that she has cheated on her husband in order to pass a lie detector test in order to win money. Apparently, being willing to answer revealing questions honestly for money is the premise of the show.

One problem: lie detectors do not detect lies.

This is one of the prevaling myths in our country. Take it away APA

Lie detector tests have become a popular cultural icon - from crime dramas to comedies to advertisements - the picture of a polygraph pen wildly gyrating on a moving chart is readily recognized symbol. But, as psychologist Leonard Saxe, PhD, (1991) has argued, the idea that we can detect a person's veracity by monitoring psychophysiological changes is more myth than reality. Even the term "lie detector," used to refer to polygraph testing, is a misnomer. So-called "lie detection" involves inferring deception through analysis of physiological responses to a structured, but unstandardized, series of questions.
The lie detector is less obvious fantasy than another iconic creation of early polygraph enthusiast William Moulton Marston: the Wonder Woman and her lasso of truth.

This persistent popular myth about lie detectors also has dangerous implications for national security. After all, Aldrich Ames passed his lie detector test.

For more on the history of the lie detector and America's fixation on it, see Ken Adler's The Lie Detectors: The History of an American Obsession. Or perhaps more convenient than having to read an entire book, see the entry on polygraphs at the Skeptic's Dictionary.


Sheldon said...

Yes, a good liar, like a double agent in Aldrich Ames, can pass a polygraph. But of course, the point is to catch all liars, not just the bad ones. And then there is the problem of people possibly having a reaction when telling the truth, perhaps because they thought of a possible lie beforehand? Who knows? And that is exactly the problem.

When I was in my late teens or early twenties, I had to take a polygraph test for a job application (moving furniture), during it I fessed up to taking a bottle of wine while working at a resturaunt. I don't know how the polygraph test turned out exactly, but I was not hired for the job.

I suppose the polygraph worked if they wanted to reject anybody who confessed to ever stealing anything on the job. But on the other hand they rejected somebody who told the truth, and would likely have never stolen anything again. On the otherhand they might have hired a good liar in my place.

Hume's Ghost said...

That's absolutely absurd that you were asked to submit to a polygraph test for a job. We've had our civil liberties eroded so much that such things (along with job drug testing) no longer even register as a wrong anymore.

I would never voluntarily submit to a polygraph test.

Sheldon said...

Yeah, well that was a long time ago, during the eighties and high unemployment, and before I had a college degree. I certainly wouldn't submit to it again.

For some of the reasons I alluded to, and the Skeptic's Dictionary entry, it probably isn't a good investment on the employers part anyway. IF the polygraph test at all detects liars, it only detects bad liars. And the Aldrich Ames entry a Wikipedia is a good article on the folly of trusting such tools.

I suppose though it make for good entertainment on reality television for people into that sort of thing.