Every self-respecting director who shoots a detective series or a spy thriller, tries to include in his creation a scene with a polygraph or at least a mention of it. Therefore, it seems that the check on the polygraph is unmistakable, and is it possible to deceive the lie detector - a device equipped with a set of precise sensors that measure every reaction of our body? It turns out that this method is not as perfect as we are presented in films.
What is a polygraph?
The prototype of the polygraph appeared in the 1920s, but the term was first mentioned in 1804. John Hawkins called the device, which made it possible to create exact copies of handwritten texts. And later this term was used to denote a lie detector. The first devices were equipped with only sensors that record the pulse of breathing and pressure. But modern polygraphs can record up to 50 physiological parameters. In addition to the listed indicators, this includes changes in the depth and frequency of breathing, data on palpitation, palpitation, facial discoloration, pupillary responses, blinking frequency, and sometimes register electrical activity of the brain. It is not surprising that the device seems to be the last resort in the search for truth. After all, it is believed that if a person lies, his voice will change, his hands will sweat, his pupil size will change, the temperature of the skin near his eyes or the pulse will increase, and the polygraph has everything necessary to fix these changes.
Is it possible to deceive the lie detector?
Many know perfectly well how to lie so that they believe you. You must first believe in your lies , if this happened, then it will be very difficult to recognize it. But is it possible to deceive a polygraph (lie detector) in this way? American scientists from Northwestern University also became interested in this issue, and led a number of studies, the results of which dealt a serious blow to the reputation of an infallible polygraph. Of course, they only wanted to answer the question whether it was possible to deceive the lie detector, and they did not intend to publish this method, but involuntarily they did it.
Dividing the subjects into two groups, they suggested that everyone speak untruth. Only the participants of the first group were tested immediately, and the second - had little time for preparation. Participants in the second group managed to bypass the lie detector, answering the questions as it should - quickly and clearly. On the basis of the study, the researchers recommended that the police be interrogated immediately after being detained, without giving the criminal time to prepare the legend. Although, probably, law enforcement officials were already aware of these nuances.
And the most surprising is that testing with a polygraph, in general, is not strictly scientific. By and large, this is not so much a science as an art, since it is necessary not only to fix the results, but also to correctly interpret them. And this task is not simple and requires a high qualification of a specialist.