Polygraph

[Bree Fletcher]

Its not all about faking, either. Here's another example. A teenaged boy is suspected of killing a local girl, and he takes the lie detector test. This is the first time he has been brought to the police, and every waking moment, he is scared like crap. While he takes it, he breakes down, and the lie detector says that he is lying, while he really was telling the truth. In this case, the innocent boy goes to Jail, the real criminal is on the loose, and police will find that the boy didn't do it after twenty years of jail life, and a load of regret.

Here, Professor X. Even if faking it doesn't actually work, (which I'm sure someone trained to can do even under stressful circumstances,) this is a good reason not to take polygraph tests at face value.

[rasterbee]

The only time polygraphs have any actual use is when you have someone that is unequivocally guilty of something yet continues to convincingly lie about it, thus proving them to be a sociopath.

[FoxyBunny]

Polygraphs serve a good use as a tool, usually one that can initiate further investigation. Missing child....bring every adult in the neighborhood in for a poly. Two of them get "lying" results. These are two people that you definitely need to look into more and question further. They may not be guilty, but you should follow up.

[Bree Fletcher]

Polygraphs serve a good use as a tool, usually one that can initiate further investigation. Missing child....bring every adult in the neighborhood in for a poly. Two of them get "lying" results. These are two people that you definitely need to look into more and question further. They may not be guilty, but you should follow up.

Definitely saves week of profiling, investigation of a much larger pool of people... But not for evidence.

[cooldude11]

Polygraphs in these cases are useless, even close to 100% being accurate, i thought the same thing once, even that small chance of that polygraph being wrong can release another criminal into freedom instead of behind bars, this is why don't use these

[acer5200]

A few months ago, I did something similar to what Rota did, I took a lie detector test as a little experiment with my local police department.

Their results weren't accurate, even with the multiple control questions that were being used, such as, "What is your name" (To which I lied yet it said I wasn't), or "What is your age".

Lie detectors are far to controversial to be used effectively as evidence in a court case. Yes, it might be able to help you get a warrant for a search of a house or building, or an arrest warrant for further questioning, but it's won't (and I think never will) be used in court.

[armbarchris]

A polygraph is like any other piece of circumstantial evidence: by itself, it's absolutly worthless, but in conjunction with lots of other evidence it's something to take into consideration.

[Montros]

I read it in this website http://www.truthorlie.com/accurate.html. It all depends on what conditions you are in (with your friends is not a controlled condition and you are relaxed).

It's gonna be really hard for some people to be relaxed when you're suspected of killing a person...Or even robbing a bank.

[Rodri]

Why don't the courts use lie detectors? I have done some research into this and found that computer polygraphs are nearly 100% accurate. Along with a fair trial and a lie detector, why doesn't the judicial use this system?

This was the original question and I say again - using a polygraph in a court of law removes the presumption of innocence. If the state want's to try me, it is their responsibility to prove I am guilty of the crime they accuse me of. I do not have to prove my innocence, they have to make a case that I am guilty beyond a reasonable doubt. There are many good reasons why this is the system that we use, rather than the opposite. It's all about the rights of the individual.

[Montros]

Here's an interesting fact from one of Penn & Teller's shows...

It seems as though Lie detectors aren't used in Courts because it isn't scientifically proven to be correct and useful as evidence.

Not Science = Not Court Certified