Challenging The 'Unbeatable' Polygraph 101
George Maschke writes "Dr. Louis Rovner, a prominent California polygraph operator, has (through PR Newswire) issued a press release titled, 'Polygraph Unbeatable, Says California Psychologist.' All too often, such publicly-made claims by those with vested interests in the perpetuation of polygraphy (a make-believe science that offers make-believe security) go unchallenged. So, I've publicly challenged Dr. Rovner to support his claim and pointed out scientific research that contradicts it, as well as the examples of several notorious spies and a serial killer who have beaten the polygraph. See, A Public Challenge to Dr. Louis I. Rovner."
Re:So... (Score:2, Insightful)
The problem is... (Score:2, Insightful)
Otherwise, I'd be good.
Re:So... (Score:1, Insightful)
"Almost no human being can beat a polygraph test"
Almost being the operative word.
Re:So... (Score:3, Insightful)
Re:So... (Score:5, Insightful)
Even if you aren't acused of a crime, consider that you can still lose your job because of a failed polygraph.
Polygraphs are bad science; They should not be used as the basis for making decisions.
Re:So... (Score:3, Insightful)
Apparently, 4% of the population constitutes "Almost no human being".
Re:Don't forget human polygraphs (Score:1, Insightful)
It also seems to me that if the myth of the polygraph is debunked and the subject doesnt believe in it, he can just look the examiner in the eye without fear and lie to him like normal.
Base Rate Fallacy (Score:5, Insightful)
Taking the claimed 96% accuracy rate as a given, suppose that 1/10K people are terrorists. If I randomly polygraph 10K peple, I'll on average turn up 1 terrorist and 400 false positives. I can only be 1/4 of one percent sure in my result.
On the other hand, suppose I know that 50% of the people working in an office are stealing supplies, but I don't know which. If I test 100 people, I'll get 4 false positives and 48 true positives. I can be 92% positive than any person who failed their polygraph steals office supplies.
The lesson is this: evidence can only be weighed in context. There will probably never be a single test that can determine the truth on its own.
The Effectiveness of the Polygraph (Score:5, Insightful)
From Skepdic [skepdic.com]:
'It doesn't appease me that many defenders of the polygraph know it is junk science but defend its use because many people confess to crimes during interviews done before or after being given the test. The machine may not be able to detect lies accurately but, as Richard Nixon said, "it scares the hell out of people." The end justifies the means.'
You fail (Score:5, Insightful)
Falls positives is what I am worried about. People being convicted because they were nervous and upset about being charged with something they didn't do.
What might have happened (Score:3, Insightful)
Polygraphs pick up body reaction. Sadly to few are used and humans are to complex to truly be able to tell why a person reacts.
A simple test is a pedophile image. Both a pedo and a normal person would react with an increased heart rate. The pedo because he is excited, the normal person because of revulsion.
Only when you would start to measure things like blood chemistry and brain activity would you be able to do a true polygraph.
At the moment it is like trying to tell if someone if is lying in an interview by crossing their arms (said to be a typical defensive position). It might just be they are hiding a stain they suddenly spotted, are cold, trying to stop their arms from moving because they are expressive people and been told off about it, just plain nervous about job interviews, trying to hide their beer belly, are just listening to what your saying and really thinking about it.
Polygraphs are a tool, not 100% reliable but an indication for investigators in wich direction they could be looking for more solid evidence.
Those who riducle polygraphs forget one tiny little detail. Most criminals are not smart, prepared, cool blooded and calculated offenders. Just as often as not the polygraph is a bluff wich the criminal will fail just because they know they are guilty and will be found out.
Smart people beating a police polygraph is a total lie. Smart people are never even questioned by the police.
Re:You fail (Score:4, Insightful)
Suspect A lies under polygraph implicating Suspect B - polygraph indicates he's telling the truth.
Suspect B is interviewed, shown 'proof' that he committed the crime, offered a deal..
False negatives can be just as dangerous if they are believed..
The largest bank of proof (Score:4, Insightful)
is in Scientology. Those individuals train for years to defeat a lie detector, even if they're not ready for it. The e-meter basically is a lie detector (it's a little hyper-sensitive on any reaction, as is shown from their "rock slam" of the needle bouncing like mad since they don't use the reduced bounce meters) that they train against for years to get to where nothing they say or do will carry a reaction (i.e. "floating").
Naturally, as was said before, you can defeat most polygraph tests with 30 minutes of training, or using the ability to answer the "wrong" question with the right answer for what they're asking you.
Re: Don't forget human polygraphs (Score:3, Insightful)
The problem with such a skill, is it is going to be damned well inadmissable in court.
You will never (I hope) see a day where someone can simply say This person is lying, and I offer my level two wizard to prove it.
At least with a polygraph they can holt up charts and the like and say "This is why we think this man is lying", and someone can refute the underlying science or lack thereof.
Taking some subset of the populace and claiming that they can detect any and all lies and should be therefore allowed to assert in court that someone else is in fact lying sounds completely unsupportable. How do we know he's telling the truth? How do we know he's even a wizard?
It might be a neat trick at parties or if you're a teacher or parent, but I can't see this ever gaining any legal standing in court, because it would be heresay.