THE STUDY NOVEMBER 10, 2011
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The polygraph test: last resort of the accused and desperate. In 2009, cocktail waitress Rachel Uchitel told two tabloids she’d take a lie-detector test to disprove charges she had an affair with Tiger Woods. Earlier this year, Lindsay Lohan offered prosecutors the same deal after she pinched a $2500 necklace. Facing new allegations of sexual assault, Herman Cain wants in too. While one intrepid Atlanta P.I. has already proclaimed Cain’s innocence based on a voice test he conducted, the likelihood we’ll get a dramatic public polygraph press conference (a la boxing match weigh-in or Maury Povich DNA test reveal) remains slim. Even so, could we have trusted the accuracy of Herman Cain’s polygraph test?
Hardly, according to a 1986 paper from The Lancet. Using previous polygraph research conducted on lying criminals, the researchers found that the device typically accused nine of ten people falsely, given a sample size of test takers among whom five percent were actually "guilty." Conversely, only two percent of liars went undetected. In other words, if Herman Cain takes a poly and fails, there’s a good chance he's innocent. If he passes, he’s still probably innocent. All of which explains his desire to take a polygraph test: heads he wins, tails the results are untrustworthy anyways. A more recent study details researchers’ ambivalence about even measuring the scientific validity of polygraph tests, one of them noting that in controlled lab experiments polygraph users “are not threatened by severe consequences of failing a test” and that using real criminals’ testimony is similarly dicey given the lack of “conclusive exonerating or incriminating evidence that can corroborate test outcome.” The most convincing argument against using polygraphs comes from the initial Lancet study: “There is no rational scientific basis for any machine to detect liars’ consistency, since there is no known consistent physiological response unique to the cognitive state of lying.” Except asking to take a polygraph test in the first place.
4 comments
And, in any case, didn't Cain follow up his declaration that he was ready to take a polygraph test with the statement that he wasn't going to do that anyway?
- ironyroad
November 10, 2011 at 8:28pm
When T.V. Westerns were popular, the (American) Indians were always shown putting a hot knife on an accused liar's toungue. The theory, we were told, was that the liar's toungue would be dry because he was nervous. Sometimes I wake up and my tongue is dry, which must mean I have lying in bed all night. Cain has already lied when he denied he knew anything about a settlement. Why do we need a machine?
- Nusholtz
November 11, 2011 at 10:06am
The obsession with the polygraph tends to be a uniquely American phenomenon in my experience. Presumably it is based on a combination of references to it in both the media and fiction (giving it credibility through repetition) and the strong US tendency to believe that there is a technological solution to everything. We can see this in our airports today as well; machines doing a job we know a person can do more reliably. However those people would be more expensive, so I guess it complements our desire to wring the greatest efficiency out of things by paying people as little as possible. From a cost perspective it probably works. Pity about the effectiveness perspective. Much like the polygraph.
- Nari224
November 11, 2011 at 12:56pm
Could Cain (or any of the Republican candidates for that matter) pass a Turing test? That's the more important question. How soon until we have the first AI President? Or do we already have him? It? Shell. Shell. Shell. I read and obey.
- skahn
November 12, 2011 at 8:14am