No, I do not Need Answer Fast. But someone told me you can’t and I find that very hard to believe.
My brother in law has. He works for military intelligence and has deliberately lied. The test givers knew he was lying, it was a test of the machine, not him.
StG
Are we operating from the premise/assumption that polygraphs work, and therefore there is a way to make a working device function improperly via the use of trickery?
If so, what scientific rigors have the polygraph stood up to?
I’ve always operated from the premise that polygraphs are junk science.
For the sake of this thread, I am using ‘polygraph’ to describe the test/procedure/device used to determine whether someone is telling the truth.*
http://www.usatoday.com/tech/columnist/andrewkantor/2004-04-08-kantor_x.htm
http://antipolygraph.org/ (site with obvious bias but good info)
http://www.psychologymatters.org/polygraphs.html
http://www.nytimes.com/2002/10/09/us/lie-detector-tests-found-too-flawed-to-discover-spies.html
Most of the reliability data we encounter is from the polygraph people themselves. This report argues that they are flawed and they have never been able to catch a spy. They are far from reliable.
Polygraphs are generally not admissable in court. Pretty much tells you all you need to know.
I was told that you think of something very upsetting during the control questions. This gets you flagged as a high reacter, and you can then lie and it shows up as background nerves.
I tried it only with the skin galvanometer, and it seemed to work.
YMMV.
Regards,
Shodan
Sounds correct. It’s not a “lie detector,” but simply a “stress detector.” So, if you can keep yourself perpetually stressed during the questioning, the operator can’t distinguish truth from lies.
The other side of the coin is true, as well: the true pathological liar doesn’t feel stressed when he lies, so he doesn’t “read” when wired up to the machine.
Mythbusters couldn’t beat it. 3/3 fails. The guy running the machine said that they have something like a 90% success rate in test conditions.
Funny, then, that repeated polygraph examinations have succeeded in catching only one “mole” in our intelligence apparatus, and missed the rest. Dr. Bob Park once suggested that the polygraph be replaced by a coin toss, since that would be right at least half the time. 
Those claims are always made by the people who run them or manufacture them. They do not test that way.
As has been observed. polygraphs are treated very warily in US courts. (In Europe, they are not considered reliable.)
3 trials is simply not a sufficient test.
Of course the guy running the machine will claim a marvellous success rate, since he gets paid if you use it.
The guy selling you a perpetual motion machine will also claim it works. :eek:
There are serious problems e.g. with false positives and people who know to get ‘stressed’ on control questions.
A Mythbusters “proof” does not take something out of junk science, I’m afraid. This “experiment” sounds particularly poorly designed. But perhaps you could flesh out the details.
It’s not the machine – it’s the interpretation of the data. Different polygraphers can give different interpretations to the same set of data. It’s also much like N-rays – what you see can be biased by what you want to see.
As George (from Seinfeld) says “It’s not a lie if you believe it.”
I know. Impressive how The Man always lies and how obvious it is.
http://www.polygraph.org/validity-research
http://psycnet.apa.org/index.cfm?fa=search.displayRecord&uid=1997-06155-008
http://www.springerlink.com/content/w430405101q23433/
http://psycnet.apa.org/index.cfm?fa=buy.optionToBuy&id=1994-28743-001
Looking at those links, a few things pop out at me:
- Knowledge of techniques for beating a polygraph are significantly effective.
- Test methodology of polygraphs can cause the results to vary widely. But the more close the test conditions are to real world conditions, the more accurate the polygraph becomes.
Assuming that most people don’t know how to beat a polygraph, we can skip item #1 and say that discounting the polygraph because of it is rather silly. It may be meaningful when you’re using it on suspected KGB spies, but not when you’re testing a 16 yo kid from the ghetto who can’t spell “wednesday” correctly.
Item #2 is a very plausible explanation for why there is a “debate” on the topic. If academia is grabbing college students and making them sit still for a few random questions, where as the government is funding full-on studies where they set up intimidating test chambers, offer rewards and punishments for innocent or guilty results (respectively), and run hour+ tests on each individual suspect by a professional interrogator, then you’re going to get vastly different results. But the important thing is that the latter is much closer to real life, which is what we’re testing.
From what I remember about the Mythbusters show, they did simple things like the tack in the shoe and biting your tongue or side of the mouth. When I Googled it, I got this guy pointing out the errors in their techniques for trying to beat the lie detector: anti-lie detector forum guy
Basically, he said they didn’t explain the difference between control questions and how you have to make sure you use the stressors during the right questions and not during the whole interview. Plus, he says that the guy they used to administer the tests is a fraud.
How does fraudulence allow a person to detect liars?
Well, if he knows in advance that the Mythbusters are trying to lie and get away with it, being a fraud would certainly help him declare that the polygraph had caught them.
Quoth Early Out:
That’s Park’s second-best quote concerning the polygraph. His best quote is that it’s very effective at detecting lies, provided that the lie one is trying to detect is lying about having an orgasm. The polygraph is a very good orgasm detector.