Do Lie Detectors Work In Real?


Lie detectors or otherwise known as Polygraphs, given the name ‘”lie-detector,” we assume that it means it can detect lies. But lie detectors are built on the assumption that if a person is telling the truth, their behavior will be calm and composed.

A test:

The Arabs had a strange test for detecting lying; a hot knife blade would be placed on the person’s tongue, in the case they were telling the truth their tongue will not get burned. The scientific reason behind this bizarre test was that when a person is is nervously excited; their tongue goes dry due to the suppression of saliva caused by nervousness. This weird test is somewhat similar to the polygraph test. The polygraph decides whether the person is lying or not depending on their heart rate, the physiological responses such as sweating and increased pulse rate. Even though these are exquisitely precise and more sophisticated when compared to the Arab’s technique, its crude.


Does a Polygraph Work?

There are many discussions regarding this question, many scientists, and renowned researchers that those who failed the polygraph eventually confessed their crimes. The lie detector test london uk is known for generating a lot of false positives, i.e., the polygraph suggested that a person was lying despite them telling the truth. The American Polygraph Association claims that polygraph results are accurate up to 90%. David Lykken proposes that the polygraphs are accurate up to 65%, a little better than the occasional 50% given by the coin flipping. While the polygraph is quite good at identifying liars, it does a horrible job when identifying people who are honest. There is half-half chance that a polygraph will say that an honest person is telling the truth or not. Polygraphs are so indirect that they force researchers to find out the pattern of lying through brain scans.


In the ordinary mode of the test, technicians depend on answers that are proven to be true so that they are provided with a boundary line against which lies can be detected when the person is subjected to any nervousness in behavior. There have been several arguments regarding the authenticity of polygraphs which is why the defense in the U.S legal system cannot provide a polygraph as evidence to prove their client is innocent. If we look at polygraphs with a scientific outlook, there is certainly no reason good enough for taking one. Although to save yourself from self-incrimination, it would be best to avoid polygraphs.

Leave your comment