Lie Detector Tests & The Moment of Truth

Do you guys remember the American game show that was aired in fairly recent history called The Moment of Truth? It was based of presenting contestants with a series of very personal and sensitive questions in front of not only the audience, but their family, friends, and husbands or wives. In order to win the money, the contestants had to answer each question truthfully, and they were hooked up to a polygraph test, which "determined" if they were lying. This show stirred controversy, as some contestants ended their relationships or marriages because of the questions they had to answer.

So, lie detectors. Are they for real? Can a machine really detect if a person is telling the truth or not? Let's discuss.

Here is a rather interesting episode of Penn and Teller on polygraph tests that basically shoots down the entire idea completely:
Part 1
Part 2
Part 3

So, what do you think after viewing this? Has your opinion changed from what you may have initially thought? What do you believe?


I'm not so much a fan of polygraph tests, as they aren't obviously reliable forms of interrogation, and they can, as its been proven, be easily manipulated. This technology is very old.

It's a good concept, we just haven't nailed down the technology needed to foolproof it. At this point, I agree the polygraph is complete BS. I've heard A LOT of stories before of people being mis-judged by the polygraph tests.

I've always found the concept of lie detectors intriguing, but I can't say that we've come anywhere near perfecting them. That show? I watched maybe part of an episode when it first aired before not watching it again. It was neat, and I even vaguely wondered at one point what it'd be like to be on the show, but really... If you get on the show, you're pretty much screwed, since the average joe doesn't really know how to fool the detector.

Person X gets asked the question, "have you ever cheated on your wife?". X then has two choices: tell the truth, "yes, I have", and end up breaking up with his wife... or lie and say no, have the detector catch him, and then end up breaking up with his wife.

I mean, really. The only way that show's any good for anyone is if they a) have no big secrets that they would bother to lie about, b) want to confess anyway, so it doesn't matter what they get asked, or c) are like that cop in the episode and can BS their way through the detector, effectively cheating the system.

I haven't watched those videos, I will later though, but right now I believe lie detectors are broken.

From what I understand, they detect changes in your heartbeat, so if you're nervous or something, like you would if you're hooked up to a lie detector, it's going to record the way your heartbeat changes, and it would say you were lying.

Also, as Lara said, they can effectively be cheated if you know how to, like, if you're trained to keep calm in any situation, you could use that to cheat a lie detector.