Penn and Teller's Bullsh*t

Two word: Gary Ridgeway. Okay, it's a name and not two words. He passed his polygraph test in 1984 and proceeded to kill dozens of women after that, becoming the worst serial killer in American history. Spies, serial killers; a lot of very bad people have passed polygraph tests, so why rely on a device that points you in the opposite direction?

And as for the fMRI, on Mythbusters 1/3 of participants fooled the device, making it 66% accurate (just like a polygraph machine). It's early in it's development and it is not 100%. Not by a long shot. It might become more accurate than a polygraph machine, but the enormous costs involved and it's unreliability will make it useless to investigators. There is no lie detector test that passes the sniff test... yet.

DYasha wrote:

Nancy Grace is a cunt -- a self serving narcissist. As a so called attorney, you would expect more. I wonder if she'll take a polygraph to answer Jon Stewart's accusation -- "Do you molest Puppies?"

I watched the one on polygraphs and that guy who ended up loosing his girlfriend doesn't know how lucky he is.

Simply put, if a polygraph can't catch a serial killer then what use is it? It's like psychics that "help" investigators. Countless hours have been wasted following leads by so-called psychics costing a lot of time, money, and maybe even lives because instead of looking for a killer, they were searching a pond based upon a "hunch" by some psychic. If it isn't accurate like ballistics or fingerprints, then it isn't a useful tool.

fucht wrote:


The real reason is cops. police, feds., etc lie in court all the time. THE SYSTEM can't have them being exposed in their lies. Forgetting to Mirandize, violating people rights, excessive force... on and on ad nasium. Expose one lie by a cop and his entire testimony is suspect/disregarded by the jury. When its an OFFICIALS word against the alleged the jury gives the official the benefit of the doubt. Polygraph eliminates this edge when the officials are subject to it. The government uses it ONLY when it suits their purpose. Cops use it to support a investigation BUT claim its unreliable when it doesn't. The federal government uses it to search for traitors etc. then convict on other evidence or an admission (to officials who can't be judged by it in court for their actions to get the confession). Typical political hypocrisy in action.

OP

Gary Ridgeway (aka The Green River Killer) didn't feel guilty about lying he felt it was justified. Emotional response is what is measured, no emotional response to lies, no registering lies. It shouldn't be that hard to come up with screening for who is responsive and who isn't, then the results in non-responsive people can be ignored and the accuracy increased. Its best used to throw doubt than to convict.

OP

It's better than chance and far from 100%. That sums up the polygraph machine. It measures stress responses which may or may not be a result of a lie. As of yet, there is no precise lie detection method. Polygraphs are 60-90% accurate and other methods are still experimental at best. And the accuracy goes down if you know methods on how to beat it. The Penn and Teller episode showed how a woman was able to beat it with just a few seconds of instructions.