With the appearance of man there was a necessity for establishment of the truth and exposure of those, who tell lies (malefactor). With the purpose of exposing and fixing the deception a special device was developed. The polygraph was called a «lie detector» from the easy hand of journalists in the 1920's.

A polygraph is the technical device that records numerous reactions of the human organism on the external elements of psychological character. In many countries of the world and in some Ukrainian companies, candidate verification is obligatory in order to exposure the candidate's professional qualities, the veracity of the information reported and real veritable purpose of employment. In the contracts of employment there is a point foreseeing passing of obligatory verification on polygraph in cases of internal investigations.

A lie detector is successfully used for testing people in various situations on condition of voluntary consent of check-up. The waiver of passing the test is an intriguing factor, indicating that a worker or applicant has something to hide.

One of the advantages of polygraph verification is that the majority of information about a person is possible to define only by polygraph. Indeed, it is very difficult to get to know negative facts of biographies or information which person hides by an ordinary way, especially if an individual does not wish to tell about it. Nobody will ever tell you anything bad about themself, but the only person who knows everything about themselves is themself.