General Question

luigirovatti's avatar

Can you explain to me why the polygraph IS reliable to detect lies?

Asked by luigirovatti (1928points) November 2nd, 2019

I know most research tells you no, but they have used it in a game show, “The moment of Truth”, to win $500,000, and, though without a doubt being sued, to my knowledge a guilty verdict must still be issued. They even released the episodes on YouTube. So, I’d like for you, as a personal favor, to play devil’s advocate and tell me why the lie detector has some practical effect (other than to scare people, I mean). For the record, the lie detector can also give inconclusive results. And, in the game show, they ask with the polygraph 50 questions circa, then they select 15 for the contestant, and they process the answers to the questions through the polygraph again. (S)he must ALWAYS tell the truth. The guests on the program (parents, friends, etc.) can stop the questions ONCE, but they have NOT idea if the next question is more difficult or easier. Last thing: 2 seasons, only 1 contestant won $500,000 but their complete attendance was NOT recorded on YouTube.

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10 Answers

Darth_Algar's avatar

They aren’t. And I wouldn’t put much stock in what’s depicted on a game show.

flutherother's avatar

I wouldn’t say the polygraph is at all reliable. It is supposed to detect physiological signs of stress in a person who isn’t telling the truth, like sweaty palms or raised blood pressure but being polygraphed is itself quite a stressful experience even if you are telling the truth.

rebbel's avatar

The only real reliable lie detector is the one used, coincidentally also a TV show, in The Wire.
Or at least as reliable.
Here at 1:38 for those in a hurry (better watch the whole 3 minutes).

Tropical_Willie's avatar

I was taught 50 years ago how to make polygraph results questionable.

stanleybmanly's avatar

Explain it? I don’t believe it .

Tropical_Willie's avatar

Too tight a shoe and other things that made the feet uncomfortable.

Yellowdog's avatar

I agree totally with @flutherother

I beat a polygraph once in 1985. I had been asked several times if I had ever been fired, or fired from my previous job, which I had. It was very stressful and severely damaged my self esteem and sense of self worth. I HAD been fired, felt a lot of remorse and guilt, and lied about it on the polygraph.

I think the polygraph test was stressful enough that there was no perceptible change in my sweat, blood pressure, etc etc. The person giving the test concluded that I was truthful and he expected would be hearing from the company hiring me. I did,

LostInParadise's avatar

I wonder to what extent the accuracy depends on the perceived accuracy of the person being tested. If you think the machine is going to catch you then maybe you will have higher anxiety when you tell lies. Alternatively, if you think the machine is not very accurate you may not register a significant difference when you lie.

Tropical_Willie's avatar

The trick is to start off with anxiety and maybe pain.

The baseline is then bogus.

Coolhandluke's avatar

Nope, not at all. Keep your cool and never change your answers. I lied during one of these polygraph tests and passed perfectly.

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