Polygraph lie detector. Chuck it or use it?

[mistermack]

I watched an edition of the FBI case files the other day.
A wealthy guy's estranged wife was killed on her doorstep by a hit-man.

The husband had a cast-iron alibi, and readily volunteered to take a polygraph test, and denied having anything to do with it.
The results were that he was telling the truth, so they focused on other leads.

In the end, they proved that he hired the hit-man, and he went on the run. They eventually caught up with him in Thailand and now he's doing life back in the US.

So what's the point of the lie detector? He was confident he could pass it, and he did. The result was a clear pass, not even marginal.

And in another case, a guy gave a clear fail in a murder case, and it turned out he had nothing to do with it.

Is it still being used? I understand that the CIA use it on their own operatives to check that they are loyal.
What the fuck?

[FBM]

It's pseudoscience. Junk science. I can't believe idjits still use it.

[rachelbean]

Huh, I thought it was ruled not admissible in court a long time ago, but that appears to not be true and it's open to the particular judge: http://en.wikipedia.org/wiki/Polygraph

[Audley Strange]

Well I know that it's probably a lot more sophisticated that previously, but I'm not convinced that it is generally effective. Even Jeremy Kyle is backing away from it, his next series will have the Dunking Chair which is believed to provide more objective results.

[Mysturji]

It's not a "lie detector". It's a "nervousness detector".

[Clinton Huxley]

Might as well use the soft cushions.

[PsychoSerenity]

Might as well use a soot covered cock in a darkened room.

[Thinking Aloud]

Might as well use a soot covered cock in a darkened room.

I am quoting that for posterity.

[Svartalf]

Might as well use the soft cushions.

Not... Not the Comfy Chair!

[rachelbean]

Might as well use a soot covered cock in a darkened room.

I am quoting that for posterity.

NOT THE SOOT COVERED COCK!!1!

[Animavore]

Apparently the way to beat it is to dilate your arsehole on each answer

[Ian]

The use of the polygraph lies not in its accuracy, but in its deterrent value. I have to go for another session next year I think (my last was in 2009). Knowing that helps keep me from doing or saying anything that could send up red flags during the test - which could happen, as its accuracy really isn't that bad. It's just not a guarantee, so it is inadmissible as evidence.

[Kristie]

The use of the polygraph lies not in its accuracy, but in its deterrent value. I have to go for another session next year I think (my last was in 2009). Knowing that helps keep me from doing or saying anything that could send up red flags during the test - which could happen, as its accuracy really isn't that bad. It's just not a guarantee, so it is inadmissible as evidence.

Hopefully they don't ask about that one time, and that....thing.

[Jason]

Polygraphs are no better than making a random guess, at least where some people are concerned. They simply give false positives and mislead the dumb machine.

Of course, a well-trained agent would know that. I think.

[mistermack]

I would give false results all over the place.
When I go through customs, I feel like a smuggler, even when I haven't got anything. I would be the worst actual smuggler there has ever been. I try to walk through, keeping a straight face, and not looking right or left. It's a wonder I don't get stopped even more.

It's the catholic upbringing. They pour guilt into you from an early age.

But the guy on the FBI files KNEW that he could beat the polygraph, and volunteered to take the test, even though he had paid to have his wife killed. That's how confident some people are of their lying ability.

As a deterrent, it seems that it might deter some people, but the wrong people. They are the people who probably couldn't keep a secret anyway.
Good liars would just have their credibility strengthened, just like that wife-killer.