A lie detector (polygraph (from the Greek πολύ - a lot, γράφω - to write) is an apparatus that is used to objectively record physiological parameters (cardiac activity, breathing parameters, electrical resistance of the skin, etc.) to analyze the emotional response to stimuli presented during conversation, interrogation.
There were different names for the lie detector at different times. The first device for detecting lies was called a "hydrosphygmometer". It was invented and used in police interrogations in 1890 by the Italian criminalist Cesare Lombroso. The device recorded the pulse rate and blood pressure of the suspects. The prototype of the current lie detector was developed in the 1920s by John Larson (a California police officer). The device simultaneously recorded blood pressure, pulse, and respiration. Larson called the device "polygraph" ("poly" - a lot, "grapho" - to write), borrowing the term from John Hawkins, who coined the word in 1804. So he named his new device for copying handwritten texts. In 1926, a student and collaborator of John Larson, Leonard Keeler, improved the polygraph. Introduced an additional channel for registering tremors (muscle tremors), thereby initiating the modern stage of "lie detection". Modern polygraphs - barking detectors can record up to 50 physiological parameters.
Lie detector can read minds, detect lies easily. No, it’s not. This myth is supported, firstly, for advertising purposes, in order to create commercial demand for this type of service. Testing is expensive and lucrative for detector firms. Secondly, to exert psychological pressure on the test takers in advance. This approach contributes to victory even before the battle begins. In the modern world, the polygraph is called a lie detector, but this term gives rise to myths. The polygraph does not read people's thoughts, does not denounce lies, but only records physiological activity, changes in physical parameters, information from which comes from the sensors of the device. Based on such reactions, it is impossible to accurately determine the nature of the process itself (lie, positive or negative emotion, fear, pain, fear, etc.). So far, there is no other way to reveal a lie, except in an indirect way, since there is no 100% reliable way to detect the physiological activity accompanying a lie.
Polygraph testing is a scientific standardized procedure. There are many doubts and criticisms regarding the scientific reliability of the results obtained. It is believed that this is more an art than a science, since obtaining results depends on the level of qualifications, experience, intuition of a polygraph examiner. First, the list of questions for testing is not fixed; the polygraph examiner selects and formulates them each time in such a way as to evoke the desired reaction in a particular subject. Secondly, after interrogation, it is necessary to correctly interpret all the variety of physiological manifestations that differ significantly in different people. At this stage, errors generated by the "human factor" are inevitable.
The suspects themselves may begin to doubt their innocence, since they believe in the high efficiency of the device. Yes, this is proven by psychologists. The fact is that before testing, the polygraph specialist convinces the tested person of the absolute accuracy of the polygraph. Before announcing the results, the police inform the suspect that they have received reliable information about his involvement in the incident in question. Some people believe this. There are times when innocent suspects knowingly make a false confession after being declared guilty by a detector test. One of the reasons is that they do not see an opportunity to convince others of their innocence. Therefore, a person decides to take the blame upon himself, to admit that he did not commit in order to receive a less severe punishment.
The polygraph is especially effective in personnel selection. This claim has not been proven. At the interview, the employer is interested in general information about the applicant. And to reveal a lie, you need to ask specific questions about specific events that happened at a certain time. General questions are asked during testing only as control questions. The likelihood of getting the wrong result increases in proportion to the degree of generalization of the questions. A polygraphic test can provide information about the employee's behavior in the past (for example, whether he used drugs in his youth, etc.), but for the employer, information is more important about what the employee's behavior will be in the future, what professional qualities are. The polygraph cannot answer such questions. This limits the possibility of using it for personnel selection.
A lie detector can be tricked. Yes, it is possible, but not so simple. There are various ways. For example, biting the tongue, tension in the legs, mental counting in reverse order, decreased sensitivity of one's own sensory analyzers (for this you need to drink some alcohol, sleep a little, drink a lot of water before testing, use psychotropic drugs). These actions will lead to certain physiological reactions that the polygraph will register. By doing so, in response to control questions, the subject thereby increases the likelihood of the desired result in testing. Reverse mental counting will allow the person not to think about the questions asked by the polygraph examiner. This will result in an undefined test result. However, the test uses control questions that make the subject think and comprehend the information. In 1994, research was conducted on deceiving a lie detector. The subjects were trained to counteract the device. Then they were tested. Mental and physical counteractions were equally effective. Approximately 50% of the subjects managed to deceive the polygraph. In addition, only 12% of the time did an experienced polygraph examiner find the use of physical resistance.
Psychopaths can deceive a lie detector more effectively than healthy people. The level of arousal in people with mental illness and pathological liars does not increase when telling a deliberate lie. Therefore, it is more difficult to reveal a lie. In addition, there were differences in testing between introverts and extroverts. Professional actors can also cheat a polygraph.
Spies and intelligence officers are trained to deceive the polygraph. Yes it is. For example, Aldrich Ames, a CIA officer, sold secrets to the USSR for many years, while successfully passing polygraph tests. Ames thrived in his espionage career because one of his skills was the ability to deceive a polygraph. With this, he dispelled any suspicions of the CIA service. Ames' KGB liaison, Viktor Cherkashin, later told the British newspaper The Sunday Times how he helped Ames successfully pass polygraph tests.
Using a polygraph is not legal. Not certainly in that way. In law enforcement agencies, the polygraph is legalized by internal orders and instructions. In commercial structures, it is regulated by the standard. RAEBUR (Russian Agency for Economic Security and Risk Management of the Chamber of Commerce and Industry of the Russian Federation) was created, which determines the procedure for conducting polls using a polygraph. The polygraph is not prohibited by law. Before testing, the subject signs a statement of voluntary consent to this type of control. A person can refuse to conduct a test at any time.
The polygraph is harmful to health. This is not true. For healthy people, it is absolutely harmless. During testing, the subject does not feel any discomfort. The polygraph specialist uses only certified equipment.
The polygraph can make a chronic illness worse. Therefore, before the study, the specialist is always interested in the state of health of the test person. If a person has a pre-infarction condition or any other serious problem, testing is best not done.