I'd guess that polygraph tests need belief into them working, thus making it work. Polygraphs should be able to (at least) measure nervousness correctly (e.g. due to transpiration), so if you believe polygraphs may work you're probably someone on which they will work (1).
In other words, long proven nonsense as long as you don't believe in it.
You're wrong, they do not magically start working if you believe in them. If you're nervous for ANY reason it will give off a false positive. Not only if you're nervous of the machine itself.
In former CIA officer Valery Plame's book Fair Game, she describes how an old hand at CIA told her that the best way to get through the polygraph is to be as detailed and honest as possible. Even on subjects that would be embarrassing, merely focussing on describing the truth and knowing that the interviewers appreciate candor can often alleviate nervousness.
I've never been polygraphed and I have conflicting views on it, but I suspect if I were ever in the same situation I'd do the same thing. They may not work perfectly, but they are a forcing function to the interviewee. Are you going to tell the whole truth in all its messy detail or not?
That said, I don't think they belong in the justice system. Someone who is already accused of a crime has to choose between either doing a polygraph and being potentially being nervous because their freedom is at stake, or denying the polygraph and looking guilty.
If I remember correctly, note this is contrary to the advice the antipolygraph sites gives. They state anything the person interviewed admits, no matter how trivial, will be used against them (e.g. "have you ever smoked pot in college?"). That the "good cop" of the interrogation is always a ruse; and that since polygraphs don't actually work, small "admissions" are a big part of the actual information gathering... including the questions that are allegedly for "calibration".
One of Obama's staff, maybe press secretary said something similar. On NPR she said when they pressed about marijuana use in the screenings, she told them flatly she used it 500+ times.
But like you said, in a legal proceeding they are terrible to use.
I think there is confusion/conflation with defendants offering to take a polygraph to prove innocence. Sometimes it’s a naive offer sometimes it’s someone who wants to “show proof” they “didn’t do it”.
Sure but it’s usually a PR stunt by the defense “see my client is willing (therefore innocent as no liar would take the test the CIA uses to expose moles)”
“We took a privately administered test by a certified polygraph administrator and my client passed with flying colors!!!”
> You're wrong, they do not magically start working if you believe in them. If you're nervous for ANY reason it will give off a false positive. Not only if you're nervous of the machine itself.
If you're just as nervous during control questions as lies then it would be a false negative. The "tack in shoe" tactic is supposed to make yourself uncomfortable during control questions by stepping on the tack and raising the baseline.
>It is to be noted that around the time Ma applied for employment with the FBI, the Bureau had a roughly 50% polygraph failure rate for special agent applicants, with many honest persons being wrongly branded as liars and barred for life from FBI employment
So either 50% of FBI Applicants were actually foreign agents AND believed in polygraphs (why would they if they were trained foreign agents?) OR it's just total bullshit. I think the "it works if you believe in it and some people do" myth is just that...
It's a very attractive idea that we can tell (even partially) whether someone is lying. We actually might be able to with an fMRI setup I think. But polygraphs should be long gone as rubbish. I have no idea why anyone in the USA takes them seriously.
> So either 50% of FBI Applicants were actually foreign agents AND believed in polygraphs (why would they if they were trained foreign agents?) OR it's just total bullshit. I think the "it works if you believe in it and some people do" myth is just that...
It's even dumber than that. From what I've heard, the big failure rate is often with respect to drugs. You're allowed to have experimented with marijuana a specific, small number of times.
In other words, long proven nonsense as long as you don't believe in it.
(1) https://antipolygraph.org/lie-behind-the-lie-detector.pdf (Chapter 3)