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It is not difficult to see in films, especially police officers, agents using a lie detector. But, did you know that this device is not just a fiction thing?The lie detector, by the way, is used in real life by the UK investigative police.

But, does this device really work? Is it possible to uncover crimes and lies because of this device?

To demystify this subject, the Secrets of the World, will show you a little bit of the polygraph, the official name of the lie detector. However, don’t get too excited, maybe it is not all the wonder that many believe it to be.

What is the polygraph?

First, the polygraph is a machine, created by John Larson, in 1921. Therefore, the word polygraph is derived from poly = “many” and graph = referring to graphics and writing.Basically, what it does is generate a lot of graphics, one after the other. They then act as measurements of factors in the human body. For example, the rhythm of breathing, blood pressure, heart rate and sweat on the fingertips of the person being examined. Now with low Lie detector test prices uk  you can find the perfect solutions available.

  • Combined, these signals indicate the person’s level of nervous excitement when answering questions. So when a person excites or when his heart rate and other factors are out of order, it can be a sign that he is lying.
  • But, of course, the polygraph is not yet a definitive proof of whether the person is lying or not. Basically, it serves as a basis for knowing if a particular question causes discomfort in the interview, and for the police to investigate why.
  • And yes, some legal decisions and criminal investigations in the United States have already been based on the polygraph test. However, in Brazil it is not allowed to use a lie detector.

How does lie detector work?

Above all, the lie detector is criticized and doubted by many. However, some experts defend the use of the machine.

Basically, supporters of the idea claim that even at times when the equipment failed, in fact, it got it right. That’s because, sometime later, people confessed that they had lied during the test.

However, other experts claim that there are “false positive” results. That is, situations in which the lie detector pointed out a person as a liar, but who, in fact, was not.

What is the lie detector hit rate? The UK Polygraph Association, responsible for UK polygraphs, however, does not agree with this type of argument.According to those responsible, the success rate of the machine exceeds 90%. On the other hand, scholars and critics claim that the polygraph’s hit rate is 50% to 65%.