Polygraph Tests- Can we trust them?

I too agree that our justice system should find a different way to determine who is lying. Before reading more about polygraph tests, I didn't realize how many false positives they produce. It would be interesting to know how many people are in jail or prison because a polygraph test determined they were lying.

I have also noticed how popular this test is in crime dramas and reality shows like Maury. I have always wanted to take one of these tests just to see if I could beat it as i have heard many claims of people being trained to beat them.

I agree that these tests should be ruled out. I am a person that gets very nervous when authority addresses me and I blush, sweat, and get a speedy heart. If i was put in front of a lie detector with detectives in front of me I guarantee I would be sweating up a storm and have a fast beating heart even if I was innocent

I agree with all of you, but just to point out, they do a base line test in the beginning. That serves as a proper foundation for the test, allowing for differences in normal heart rates of different individuals. It would be very interesting to take part in the test, and see how I fare. Speaking of falsifiability, in one episode of Lie to Me, The main character had an army officer take a relaxant that would keep her heartbeat stable at all times during the test, thus botching the results. I thought it was interesting.

I agree completely that this test needs to not bear as much weight as it does. It should still be taken into consideration but should not determine anything, just offer more evidence.

I also agree, but it should also be taken into consideration that guilty people can still lie and pass the polygraph test. This is possible by causing the readings to match what a normal lie would look like when they are doing the baseline readings. Poking yourself with sharp objects and causing yourself pain causes your "truthful" statements to show up with the same readings that the "lie" statements have.

The book? Which book?
With whatever faults you perceive due probably to your lack of detailed knowledge regarding how polygraph really works, there is just no better method of truth verification commonly available.

The National Acadamy of Sciences concluded from the research they reviewed that properly conducted polygraph examinations produced correct results significantly greater than chance (85% to 97% in scientific studies). Compared with voice stress analysis which has a verified accuracy rate actually less than chance.

Perfect? No it is not.
Valuable diagnostic tool? Absolutely yes.

I feel that polygraph tests aren't reliable enough for them to be used in convicting criminals. They don't tell if someone lies, they just see if there is a changes in blood pressure, and one can alter results by doing certain things during irrelevant questions. The number of false positive is too high to be trusted.

Good point. Not only is the machine occasionally incorrect, just giving the test can give a bias conclusion. For example, if someone is on trial but fails a lie detector test, how is one supposed to convince a jury of innocence? On the other side, if a person on trial passes the test, they aren't off the hook anyways. Not only is the test faulty, but its functionality isn't used properly. It's more of a scare tactic than anything else, that happens to measure if someone is stressed. It has a place to aid police, but the results lead to questionable assumptions.

From my point of view, if I were innocent in a crime committed by someone else, and was put up to this lie detector test, I would sweat and feel anxiety just because it's a stressful situation. Someone is getting blamed or a crime they didn't commit, and this little machine conducting heart-rate and such is supposed to prove whether you're guilty or not. I don't think this is a very healthy and proficient way to go about proving someone is guilty....or innocent.