The lie detector is an instrument that comprehensively analyzes the involuntary physiological reactions of the organism, which are emotional responses to important questions for the person. In a standard detector, this is the respiration rate and heart rate, skin-galvanic reaction, muscle tone, and electrical brain activity.
The person subjected to verification is first asked neutral questions, the answers to which are known in advance. Thus, the natural background of the reaction is revealed. Then questions are entered, the answers to which are of a fundamentally important nature. If it is possible to fix the change in the reaction, this serves as a basis for questioning the sincerity of the answers. That is, if a person, answering "yes", is tense - this should be regarded as "no", and vice versa.
The idea and history of invention
From time immemorial, different nations used ingenious methods to help identify a person with an unclean conscience. A story about how a thief clasped his hat when a wise judge cried: "The thief’s hat is on fire!" - with different variations is found in the epic of different nationalities. The Chinese once had a custom: accused of stealing during the trial had to keep in his mouth a handful of dry rice. If he, after listening to the accusation, spit out the rice dry, then confessed guilty. They proceeded from the fact that fear causes a number of changes in the human body, in particular, decreases salivation - "dries up in the mouth." Therefore, for a thief who is afraid of exposure, the rice remains dry.
The lie detector was invented in the 20s by our compatriot A.R. Luria. The method he proposed was fairly simple. From the subject was required in response to the presented word to answer the first word that came to mind and at the same time to squeeze the rubber pear with his hand. Words were presented very different - both neutral and those that could have a special emotional subtext for the subject. In the event that the stimulus provoked some hidden experiences, it was possible to fix some delay in the verbal and motor reaction. Luria’s experiment was used in forensic practice. With his help, in a number of cases, it was possible among several suspects to identify who was subsequently convicted as a criminal by subsequent investigative procedures. This experience of Luria was summarized in the book The Nature of Human Conflicts, which was published in English in New York in 1932 and has not been published in our country since that time. And in the US, the development of this problem was actively continued and resulted in the creation of a lie detector in its modern modification.
Do Lie detectors lie?
In some countries, lie detectors are prohibited because they violate the freedom of the individual, but the main claims to them about the reliability of the data. In the USA, where interrogations on the lie detector have been practiced for a long time, an entire association of victims of the lie detector has already appeared. Many of its members were subjected to unfair discrimination or even served a full or partial imprisonment before the accusation against them on the basis of "scientifically grounded" interrogation by means of a lie detector was accidentally refuted.
The manufacturer of VOICE lie detectors asserts that in 90 percent of cases the voice detector produces an accurate result. However, the studies of Mitchell Summers from the University of Washington, published in the German weekly Zeit, show an error in 63 percent of cases - just as well, you can throw up a coin.
Fixing the presence of an emotional reaction, the standard detector can not say anything about its nature. Rapid breathing and palpitation can be a manifestation of excitation (both pleasant and unpleasant), fear, anger, enthusiasm and many other emotions.
Such an illustrative example is known. In the US, the interrogation on the detector was subjected to pretenders to the position of cashier in the supermarket. One woman was not hired because of alleged dishonesty. For example, she was asked: "Your mother approached the counter. Do you find it less than the amount she bought for?" The subject, as well as she should, answered-no, but the device fixed - she lies. The truth was that this woman recently buried her mother, and the mention of her caused a painful experience.
Prepared man is easy to confuse the lie detector. Used as "external" techniques - "ragged" breathing, barely noticeable delayed responses, and internal techniques - memories of anxious or exciting situations. If you worry yourself about other matters, your worry on the issues of control can no longer be proved...
Lie Detector is only an instrument, and the success or failure of a case depends on the qualifications of those who participate in this "duel". Prepared and skilled expert with the help of the lie detector of an inexperienced liar will expose. An experienced liar confidently misleads and defeats the lie detector if it is run by a specialist without psychological training. If this is a duel of two professionals, the result, like any duel - is unpredictable ...