Your own BS detector is probably better than any polygraph machine

We’re told that Christine Ford, Judge Brett Favanaugh’s accuser, has passed a polygraph exam which showed no deception. What then, can we now know about Christine Ford? Nothing. Not a thing. It would be the same if the machine had said she failed. We’d still know nothing we don’t already know.

Lie Detectors are simply not reliable. Claire Berlinski says lie detectors are voodoo. Junk science. She’s exactly right. It’s scientific quackery. The machines are worthless, at least for the purpose of determining the truth about anything.

During the Watergate hearings it was said that someone, I don’t remember who, should be given a lie detector exam.  North Carolina Senator Sam Irvin (1896-1985) objected. He dismissed polygraphs as 20th Century witchcraft.

Things are little different today. Polygraph examinations are now 21st Century witchcraft. Flipping a coin is at least as reliable a way to the truth. Perhaps more so, if someone’s statement must be a lie or the truth, either one or the other, flipping a coin gives us a 50% chance of finding the truth. Trouble is, we still wouldn’t know which one was the truth and which the lie. Polygraph exams are even less trustworthy.

Except in New Mexico polygraph results are not admissible as evidence in court. Something is seriously wrong in New Mexico.

Polygraph results aren’t admissible as evidence because they aren’t reliable evidence. A polygraph examiner is simply giving his opinion of whether someone is lying or telling the truth. His expertise and experience does not make him a better finder of truth than the jury because the scientific knowledge that his opinion is based upon is itself based on an unreliable system.

There is no reason to allow the polygraph examiner to offer his opinion to the jury because determining credibility is not specialized knowledge beyond the scope of the average juror. Expert opinion is admitted in trials only as to specialized knowledge which the average juror would not be expected to know. If the opinion is on a matter of general knowledge within the scope of the jury, expert testimony will not be allowed. Especially not from an expert in junk science.

Admitting polygraph results in a criminal trial undermines the jury. It may diminish their role of determining the credibility of witnesses. That role belongs exclusively to them. There is the danger that the jury may give undue credibility to polygraph evidence.

Sensing whether a witness is lying or telling the truth is the central function of a jury. Lie detector machines can interfere or even corrupt the role of the jury. They never help because they are in essence just another opinion, and likely a less trusted one.

Reliance and belief in polygraph tests may allow criminals to escape while the innocent are convicted. Yes, that is how bad it could be if this stuff were allowed to find its way into a criminal trial. For that reason, it should not be used in any other setting such a hiring and firing from employment. It makes as much sense as flipping a coin or drawing tarot cards.

Claire Berlinski ends her essay by remarking on Mike Pence’s offer to take a polygraph to prove that he was not the author of the anonymous New York Times op-ed:

That Mike Pence has offered to take a polygraph tells us exactly what we’d know from studying his horoscope—nothing. That he would appeal to the polygraph tells us that he is credulous or cynical. That Christine Ford has “passed” one tells us what we’d know from learning that she is a Virgo whose ascendant is in Libra—nothing, again. That she is appealing to it tells us that she is suggestible, manipulative, or manipulated. Reporters who discuss her polygraph results uncritically tell us exactly the same thing about themselves. None of this means that they’re lying—it just means that they’re dumb.

I knew Mike Pence was not the author of the anonymous New York Times politically motivated rubbish the moment I heard that someone had suggested it. As any ordinary being who has lived in and paid attention to the world for a while I have a better bull shit detector than any machine. I bet you do to.


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