Why don't we use lie detectors to solve cases/trials?

Lie detector tests (polygraphs) read your reaction to certain questions, not just your answer of ';yes'; or ';no';. The issue with this is that if your mind wanders or a question asked triggers something, a reaction or thought, it is recorded as a jump on the meter. The person giving the test will note this and ask follow up questions depending on how you reacted to certain base questions. They might ask ';when i asked this question blah blah blah, you showed a change in your levels, why is that?'; So the reason they arent used in cases or trials like you are thinking is because of this issue of perception and emotional/mental triggers.Why don't we use lie detectors to solve cases/trials?
Lie detectors aren't 100% accurate. They only detect what the person being tested perceives to be a lie (unless the person is trained to pass tests by meditation).





For example, if a person honestly believes a lie to be truth and takes a lie detector test about that lie...the test will show them to be telling the truth, when in reality it's a lie.





Let's use an example. We all know President Lincoln was a Republican. But if a person was taught that Lincoln was a Democrat and then hooked up to a lie detector and asked if Lincoln was a Democrat...they could answer yes (a lie) and pass the test (telling the truth).Why don't we use lie detectors to solve cases/trials?
They are 100% reliable for what they test, but what they test is simply pulse, respirations, and sweat on the finger tips.





The whole ';lie detector'; part is all on the shoulders of the one administering the test. And as people are fallible, the determination cannot be 100% accurate.





People can't beat the machine so much as they can just outwit the person administering the test. It's a psychological thing.
100% accurate my @ss





they dont tell you anything about whos lying or telling the truth


they only measure nervousness


so say your nervous about being in the room or being hooked up to a machine... bamn!! you fail


your a lil shaky about being questions... cklvhdfsj you failed again


or maybe you just dont like the pressure .... dsfgds you failed even though you just said the sky is blue and water is a liquid


you still failed... they are junk. period....
They can be beaten too easily to convict someone based on the results.
lie detectors are not reliable.

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