Think about your favorite criminal justice TV show, when the detective thinks the suspect is lying and wants to incriminate him, what does he do? Gives him a lie detector test! The lie detector test, also known as the polygraph test, has been a socially acceptable way of detecting lies in the 20th century. But is it really valid? The polygraph test is based off of lie detection tendencies such as the Pinocchio response; a physiological/behavior indicator of lying. Statistically it does better than chance but yields a high rate of false positives. This is due to the fact that the polygraph test doesn't specifically detect lies, it detects arousal. The suspect could be experiencing arousal because he's nervous of being wrongly convicted of the crime, and this would create what looks like a "lie" on the test. This happens more often then not. Well if the polygraph test isn't as reliable as expected, is what about human instinct? Most of us are pretty confident of our skills at detecting lies. Although we are also better than chance most of us only achieve a 55% accuracy rate and it's shown that there's little to no correlation between our confidence of detecting lies and our abilities. Both personal instinct and the scientific route of the polygraph test are better than just flipping a coin, but they are nothing to fully rely on.
Liar, Liar, Pants on Fire
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I love how tv shows about crime and police matters try to make this look like a reliable method. I know that when I'm under pressure, I show signs of uneasiness, my heart rate increases as well as my breathing. My friend's dad was a police chief for about 15 years back home and not once has he recalled using this outdated system. Policemen and other investigators are better off simply questioning suspects than relying on this method.
It's always kind of funny to see TV shows and movies depict lie detector tests as the end-all and be-all of whether or not someone is lying. It's also frustrating to see lie detector results hold any credibility in court when we know they are not that accurate. Hopefully most people know lie detector tests have many flaws though.
Interesting topic! I think the lie detector test could be a helpful starter tool and investigating suspects but due to the high rate of false positives and how unreliable it can be, I find it astounding that results can hold up in court. These tests should not be used to convict a person, but rather as a means to get to the truth.
Yes, it's interesting that despite the amount of confidence we have in discerning lies, our accuracy, or lack of accuracy remains the same. We assume that machines are not as susceptible to human error but the polygraph test simply isn't a robust enough tool for high stakes decision making--especially when it means being convicted of a crime or not. So many factors can facilitate false information such as a person that is highly susceptible to anxiety. Conversely, a guilty person who has the ability to exert control over their physiological responses to stress could get a false negative.
I think it would interesting if we could actually invent a test that was accurate in finding lies. I know personally I find it easier to detect lies from people that I know very well, but it's pretty much up to chance with strangers. I know my friends each have their own personal "twitch" when they lie so it's easier to read them.
I think the media presentations of lie detectors as infallible have really affected public belief in their accuracy. It's really interesting to learn that lie detectors don't work as well as they're portrayed! Also, 55% accuracy? I guess that in terms of evolution, detecting lies must not have been very important to our ancestors!
I think this is a very valid point and we should look at other shows especially ones like Maury. They consistently use lie detectors like the polygraph to determine life changing decisions i.e. the decision if you cheated on your wife or not.
There is an episode of Seinfeld in which Jerry is dating this policewoman/detective who subjects Jerry to a lie detector test to find out if he watches Melrose Place. Jerry denies ever having watched the show (even though he has) and he thinks he can beat the polygraph test so he agrees to do it. His friend George reminds him before the test that "it's not a lie if you believe it" which I feel is true and supports the idea that the polygraph is not infallible. It's almost impossible to tell if someone is telling a lie if THEY themselves think they are telling the truth - because then it's not truly a lie... is it?
I like the title and the picture! I think that lie detectors shouldn't be used for serious matter. Like for police work and other matters like that or even things that are important in life. I think they were more useful when the first were used, before people figured out how to beat them.
You're right, in popular culture the concept of lie detection has really been hyped and created a false image to the average person. I really like the examples some of the other commenters have given and can't help but laugh when I think of the scene in Meet the Parents where a polygraph is used. Anyways, to my point, I believe that we should simply recognize the entertainment value of lie detectors and place that concept on a shelf with all the other ridiculous ideas that criminal investigation shows given us!
I have always been hesitant to believe the lie detector test is a good way to detect lies. This is because, like you said, it detects arousal, and there are plenty other ways to get aroused apart from lying. Being grilled by detectives or cops about, say murdering someone will likely get a number of people nervous, and therefore causing them to show arousal on the polygraph. They continue to rely on the test though, even though they know of it's inaccuracies, I know that I wouldn't be too confident going into a polygraph test, even if I was innocent.
I personally think that lie detectors are a very bad way to try and detect truth because of how it actually works. Because it only detects arousal, I think it can be very misread. I know that personally if I were to be put to a lie detector test, it would come back positive. The reason for this is because in that situation I know I would get extremely nervous whether or not I was lying. This is exactly why I do no think that they are valid. Have you ever been in a situation where someone accuses you of something, and even though you know for a fact it isn't true, you still get nervous? Well this is exactly how I would react for a polygraph test, so I know that in would never go well.
great post :) i do believe that lie detectors should not be used because I think it will wrongly accuse people. I know I would get nervous if I was taking a lie detector test, who wouldn't. I think it is very difficult to detect a liar unless you really know the person.