Even an experienced investigator with many years of experience cannot always discern whether a suspect is telling the truth or deliberately lying. And then a special device called a polygraph comes to the aid of law enforcement and security services. Based on the results of the examination on such a "lie detector", it is possible to draw a well-grounded conclusion about the sincerity of the subject.
Polygraph as a lie detector
What is a polygraph? This is a sophisticated and high-tech device that can be used to record a variety of physiological parameters: heart rate and respiration, blood pressure, galvanic skin response, and so on. The testing procedure is completely painless, although it makes the subject pretty worried about his fate.
The sensors of the device are attached to parts of the body of the person being tested. The resulting data is sent to a computer, which draws several graphs. By their appearance, the specialist makes his opinion. Not every certified psychologist can correctly interpret the measurement results. As a rule, polygraph specialists undergo in-depth preliminary training.
During a detector test, the subject is asked a series of questions, most of which relate to facts that are relevant to the case. It is believed that a person's reaction to questions that are significant to him leads to a significant change in the measured parameters. Experts say that it is almost impossible to deceive a smart device, even if a specially trained person who knows the principles of a polygraph is undergoing the examination.
What is the polygraph used for?
The polygraph is used today to solve a variety of tasks. It is used in law enforcement to identify persons involved in the commission of crimes. Based on the results of the examination, an expert opinion is drawn up, which, however, does not serve as unconditional proof of guilt, but is considered by the investigator and the court along with the entire body of evidence in the case.
Lie detector is widely used in private business. In large corporations, there are special units that are part of the security services or work with personnel. Polygraph assists with loyalty checks, internal investigations and in-house theft proceedings.
One of the directions in the use of a polygraph is the study of candidates for certain positions. The smart device helps to identify the moral and psychological qualities of personnel and to recognize those persons who can potentially be included in the so-called "risk groups". At the same time, the techniques used for these purposes may differ significantly from the techniques used in forensic science.
