Interesting facts about the polygraph (lie detector). How does a polygraph work and can it make mistakes?

Previously, only criminals and the military had to deal with lie detectors. Today, anyone can undergo a polygraph test. But the detector can also be fooled. We'll tell you how to do this.

Polygraph. Where and when.

The polygraph is an old invention. The ancient Hindus asked the subject neutral and leading questions, and he beat a gong for each answer. It was believed that during a false answer he would hit the gong harder than usual.

In ancient China, the suspect would put a handful of rice into his mouth. If he remained dry, then the criminal was found guilty - salivation decreases due to stress.

The polygraph that is used today is the same gong and the same rice. Only with wiring. It was brought to fruition and patented by a man with the poetic surname Keeler. However, there were detectors before him. And the “credit” for their popularization belongs to Cesaro Lombroso.

Why do you need it?

Before you decide to deceive the polygraph, think - do you need it? A deliberate mindset to deceive, especially if you are poorly prepared, can ruin everything. You will behave unnaturally, this will arouse suspicion and will be interpreted not in your favor. If you are too nervous, it will not be interpreted in your favor. If you are too dispassionate, this will also incriminate you. Therefore, if you are still serious about fooling the polygraph, prepare in advance. Forget about buttons in shoes and other “tricks”. There are more effective methods. They are developed not to hide evidence, but to protect the natural human right to personal life. There is even a social movement "anti-polygraph". His motto: “Their right is to try to find out all the ins and outs about us, our right is to send them all to hell... This is democracy.”

Where to start?

It's better to start with a general attitude. The calmer you feel, the better. Lie detector tests are carried out by trained people. Take a liking to them. Let them be your colleagues during the interview.

Get rid of the reverence for the polygraph and polygraph examiner in advance, as well as the feeling of guilt (it will be instilled). A lie detector is just a machine. It only registers your condition. Let the polygraph be just a detector for you, without any “lies”.

It is important to understand that the polygraph examiner will try to take you out of your comfort zone. His questions may seem provocative, the chair may seem uncomfortable, the lighting may seem irritating. However, with the right level of preparation, you can do it.

How does a lie detector work?

The polygraph has no intelligence. This is a mechanism with specified calibration parameters. It tracks sweating, heart rate, breathing, skin tension and muscle contractions. Latest models have greater sensitivity and record more parameters.

During the test, the polygraph examiner will ask questions. They are divided into neutral (which should not cause an increased reaction in you), test questions and trap questions.

Important: do not rush to answer. Find a pace that's comfortable for you and stick to it. The “silent answer” is also practiced - you are asked to think about the answer to a question, but not say it out loud. Rehearse that too. The main thing is not to be fooled by provocations.

The work of the polygraph is often duplicated by external video surveillance. Stay calm. Make it clear: no one is blaming you, they are working with you. As a rule, the interview is conducted in a static state - remember it and try not to fidget.

The first level of control is breathing control. Many candidates “cut off” with a “breath of relief” after a problematic question. This cannot be allowed. Breathing can regulate heart rate and blood pressure. Special gymnastics, yoga, qigong and sports can help you learn how to do this. Take care of this in advance. The ability to breathe is also useful in everyday life.

Play "the fool"

One of the most effective ways fool the polygraph - play the “fool”. You come to the test and start answering all the questions frivolously and haphazardly. The polygraph can get confused, since setting the required calibration when interviewing schizoid-type personalities is a difficult task. The main thing here is not to overdo it. Excessive “stupidity” will be perceived in a negative way.

And people are all actors

Professional lie detector actors are not afraid. The ability to get used to a role until you are completely immersed in it perfectly masks the body’s reactions. The method of “identity substitution” is also being studied by intelligence officers. For them, passing a polygraph test is an easy walk in the autumn forest. If you have not studied acting and are not sure that you are able to “play the role” to the end, we advise you to abandon this method.

Medicines

We will not recommend using medications to lower blood pressure. Firstly, it is unsafe, especially for people with hypotension. Secondly, a too weak reaction from the body, as well as a too strong one, is a sign that you intend to hide something. Thirdly, in serious organizations, in addition to a polygraph test, the subject may be asked to take tests. Therefore, medications are the most ambiguous way to fool a lie detector.

This is a complex and high-tech device with which you can record a variety of physiological parameters: heart rate and breathing, blood pressure, galvanic skin response and so on. The testing procedure is completely painless, although it does make the subject quite worried about his fate.

The device's sensors are attached to parts of the body of the person undergoing the test. The resulting data is sent to a computer, which draws several graphs. Based on their appearance, the specialist makes his conclusion. Not every certified psychologist can correctly interpret measurement results. As a rule, specialists undergo in-depth preliminary training for work.

During the detector test, the subject is asked a series of questions, most of which are questions that are relevant. It is believed that a person’s reaction to issues that are significant to him leads to a significant change in the measured parameters. Experts say that to deceive smart device It is almost impossible, even if the examination is carried out by a specially trained person who knows the principles of operation.

What is a polygraph used for?

The polygraph is used today to solve the most different tasks. It is used in law enforcement to identify persons involved in crimes. Based on the results of the examination, an expert report is drawn up, which, however, does not serve as unconditional evidence of guilt, but is considered by the investigator and the court along with the entire body of evidence in the case.

Lie detectors are widely used in private business. In large corporations, there are special units that are part of the security or personnel services. The polygraph helps in conducting loyalty checks, internal investigations and in theft proceedings within the company.

One of the areas of use is studying candidates for certain positions. Smart device helps to identify the moral and psychological qualities of personnel and recognize those individuals who could potentially be included in the so-called “risk groups”. Moreover, the techniques used for these purposes may differ significantly from the techniques used in forensic science.

The first lie detection device was called a hydrosphygmometer. It was used by the Italian criminologist Cesare Lombroso. In the 1890s, it was used by a criminologist to measure the blood pressure of suspects while they were being questioned by police. Lombroso claimed that he could tell when criminals were lying. Showing photographs related or unrelated to the crime, he simultaneously recorded the pulse and blood rates of the suspects.

The polygraph became famous after an investigation in 1902. Then Lombroso was involved in the investigation of a criminal case of rape and murder of a girl. During the interrogation of the suspect, the scientist used his unusual device. Although initially all the facts spoke against the suspect, Lombroso came to the conclusion that he was innocent.

He detected slight changes in the subject's pulse as he did various mathematical calculations in his head. When the suspect was presented with images of injured children, the recorded pulse recording did not show any sudden changes, including when viewing photographs of the murdered girl. The results of the subsequent investigation convincingly proved that this suspect was innocent of this crime.

The prototype of the modern polygraph was developed in the 1920s by John Larson, a California police officer. The device he created provided simultaneous recording of blood pressure, pulse and respiration. Using this device it was carried out large number checks of persons suspected of criminal offenses.

Larson called his instrument the "polygraph", borrowing the name from John Hawkins, who coined the term in 1804. This was the name of the machine he invented for creating exact copies handwritten texts. The name “polygraph” comes from two Greek words – “poly” (many) and “grapho” (write). This machine was used by many in the 19th century, including Thomas Jefferson, the third President of the United States and author of the Declaration of Independence, but it was John Larson who first applied the word “polygraph” to a lie detection device. Subsequently, this term became firmly established.

Where is the polygraph used?

Many reputable domestic companies, focusing on the experience of foreign colleagues, practice testing applicants with a lie detector, also known as a polygraph. About ten years ago, such “truth sessions” seemed like something out of the realm of spy detectives, but now it is an everyday thing in structures that have nothing to do with state security. The lie detector is used in many areas, but the main ones are the interrogation of offenders and the screening of applicants when applying for a job.

How does a lie detector work?

Anyone who has already taken a lie detector test knows that the polygrapher alternates meaningful questions (for example: “Have you ever been accused of embezzling corporate funds?”) with control questions that have no connection with the direct purpose of testing (for example: “Have you ever... or deceived your spouse?”). At the same time, the printer monitors the readings of several sensors (galvanic skin reflexes, cardiovascular activity, thoracic and abdominal breathing, etc.).

The basic principle of the polygraph is as follows: the physiological reactions are stronger, the more important and significant the question asked is for you. As a rule, a person who is not involved in a case that interests interrogators reacts approximately the same way to all questions: those that are significant for the case and those that are not significant. And for those involved, significant questions cause uncontrollable tension.

Usually, before the actual lie detector test, all the questions that will be asked are discussed with the test taker. The topic of the test is discussed in advance to avoid an uncertain reaction to an unexpected question. If you ask a person directly without preparation something like “Did you sleep with your boss’s wife?”, he simply may not understand what is happening. He will start to get nervous or hesitate to answer, even if he has never done so. Or he will be very surprised - and the polygraph shows approximately the same reaction to lies and surprise.

During the preliminary discussion, you can already decide how you will answer. Knowing the topic and an approximate range of questions, you can take advantage of this. Banish the real picture from your consciousness and create a “legend” that is beneficial to you: a bright, emotionally charged image that will displace the real one. With developed imagination and self-hypnosis skills, this can help you outwit the polygraph. The key here is to force yourself to believe in this alternative reality, and not just imagine it in every detail.

And the main difficulty is “not to think about the white rhinoceros”, to forget for a while about how everything really happened. Otherwise, the real picture in your mind will overlap with the imagined one. Two mutually exclusive images will simultaneously evoke the psychic. You will begin to demonstrate delayed reactions to questions and other artifacts. They will show that you are constructing an imaginary event (or, more simply put, lying) and this will be recorded by a polygraph as evidence of your lies.

Before the main test, the so-called tuning (pre-test) interview to “calibrate” your answers. Your psychophysiological indicators in a normal state are studied. Sensors record upper (chest) and lower (abdominal) breathing, heartbeat, blood pressure, tremor (shaking) and electrical reaction of the skin. Next, the tests find out how the indicators “jump” when the test taker is asked questions that are significant to him. Usually they are quite simple: “Is your name so-and-so?”, “Do you have a family?”, “Do you intend to deceive the polygraph?”

Your reaction to a deliberate lie is also studied. The polygraph examiner calls several names, including yours. You must lie, that is, say that the name being spoken is not yours. This way it checks how you react to a lie and how the detector records it. For a similar purpose, you may be asked to write down a number from several suggested ones, choose a playing card, put some kind of figure in your pocket, etc. The polygraph operator then “guesses” the subject by analyzing your reactions.

A funny detail: in many instructions for polygraph operators, when “guessing” they advise not to limit themselves to the analysis of psychophysiological reactions, but to be safe, to resort to cheating techniques - marked cards, hidden video cameras... Such petty cheating is considered acceptable. After all, among other things, the preparatory stage should break the test taker’s will to resist and convince him of the futility of trying to deceive the polygraph. Therefore, during the preliminary demonstration, they strive to completely eliminate the possibility of a “puncture”.

The main test can take several hours. The questions are read out, you are asked to listen carefully and answer honestly “yes” or “no.” After each question there is a pause (15-20 seconds) during which the psychophysiological reaction to it is recorded. The polygraph records when your “heart skipped a beat,” where you held your breath, what question was followed by a “sigh of relief,” and where your hands trembled and your knees vibrated. Here are some signs of emotional tension in response to the presentation of a significant question.

They may not be in your favor:

the magnitude of the skin reaction increases;
the pulse slows down, followed by a compensatory increase in heart rate;
holding the breath and slowing down its rhythm, followed by a compensatory increase in the rhythm and depth of breathing;
changes in inhalation/exhalation time, inhalation pause and exhalation pause;
increased muscle tremors

To disorient the interviewee and break down his protective barriers, conditions and wording may change. The same question may be presented many times. Questions on the same topic can be formulated differently. You may be asked to answer “yes” to all questions, even if you have previously answered “no” to them, to find out what your reactions will be if you answer yes. Or vice versa - give only negative answers. There is also a “silent answer” - the test taker is asked only to think about the answer to the question, but not to say it out loud.

During the survey, “filler questions” are used on neutral topics that, in theory, should not cause excitement (“Is it Monday?” “Are you sitting on a chair?”). Experts suggest including more questions in the test that require a known truthful answer. After them, it will be more difficult for a person to lie, and the corresponding physiological manifestations will become more noticeable.

There are also trap questions regarding the details of what happened (for example, theft). They are unknown to the innocent, but will cause a strong reaction to those involved in the crime. Often the question lists keywords and facts. “What did you take from the safe? Mobile phone? Gun? A pack of condoms? A bunch of keys? “How long has it been since you last used drugs? Week? Month? Year? Five years? “Do you like to drink alone? In the company? In the morning? In the evenings? For days on end? “What bribe did you receive? One hundred? Two hundred? Three hundred? Five hundred thousand? As you approach the correct answer, signs of anxiety increase, and then relax as you move away from it. Although outwardly it may not be noticeable to a person.

To distract the test taker's attention, significant questions are made more difficult. The unknown is presented to the test taker as the known: “Did you hide the package you stole there?” A person, by inertia, can “get carried away” and answer “yes” or “no”. And any unambiguous answer to such questions already contains indirect recognition.

There are also security questions that should excite even the innocent (“Have you ever taken something that didn’t belong to you?”). Everyone has committed such acts at least once in their life, so it is assumed that for innocent people, control questions should cause more excitement than questions directly related to the essence of the case. A negative answer to a control test question indicates that the person being tested is lying.

Methods of deception

Today there are several ways to deceive a lie detector. Some of them depend on the preliminary professional training of the test taker. So, for example, employees or former employees of special services who are well familiar with the principles of the polygraph or have repeatedly used it in practice will be able to deceive a lie detector. In addition, during their professional training, they undergo a special course on countering polygraph testing, because their work involves the need to maintain professional secrets. Systematic training brings their reactions to the level of unconscious automatism.

Acting

If a person is a professional actor, well acquainted with the technique of implanting himself into the image of another person, absolute transformation, up to complete identification with him, including physiological reactions, he will also be able to deceive the polygraph. After all, the main thing is to convince yourself of the truthfulness of your lies, since the lie detector evaluates reactions, and not the actual truthfulness of the answers.

Drugs

In addition, there is a so-called pharmacological way to fool a polygraph. This is the use of specially selected sedatives, medications that affect blood pressure, and alcohol. The point is to prevent the polygraph from assessing your true reactions to the questions asked and to increase the number of errors. By the way, after a hangover or lack of sleep for several days, the body’s reactions will also affect the level of objectivity of the polygraph.

Let's use our brains

If you gesticulate excessively, shake your head, or tense your diaphragm or abdominal muscles during a lie detector test, your answers can also be falsified. You can, on the contrary, resort to psychological tricks: form a parallel focus of attention, concentrate on mental activity not related to the questions asked, for example, remembering the multiplication table.

Secret way

If the above options for deceiving the polygraph do not work out, you can even resort to the so-called chemical method of deception. Because sensors that measure skin conductivity are placed on your fingers, their tips can be treated with sweat gland blockers. This can be alcohol or salicylic-zinc ointment, sold in any pharmacy. The main thing is that the polygraph examiner does not notice traces of processing, and then the main channel for obtaining information by the detector will be blocked.

How to behave during the test?

Do not forget that the operator who is sitting in front of you is a simple person and, like everyone else, he also sometimes has emotions. Simply, he is obliged to hide them from us, because... man is at work. But we know that. Show him that you are also a simple and, most importantly, adequate person.

If you are beautiful girl, then it’s hardly worth trying to evoke sympathy from the operator. The main thing is to show your adequacy and positive attitude towards this procedure. The operator should not think that something is annoying you or that you are afraid of something.
Be calm. Do not make sudden movements with your hands or head, do not roll your eyes, do not look around the room, do not ask questions. All this can provoke additional questions from the operator and increase your blood pressure and pulse. This is of no use to us at all!
After a trial set of questions, the actual testing session begins, which is recorded on a video camera. Stay calm. Look straight ahead. Focus your gaze on a neutral object: a wall or curtain. Oh, by the way, don’t wear anything bright to your session. Even a small red scarf can greatly affect your heart rate if it enters your field of vision.
Everything should be neutral. Preferred colors: gray, beige, pale green. Imagine yourself in an environment where you would be as calm and comfortable as possible.
You answer, without thinking, what you need and again enjoy the sun in the clearing. It’s a pity that you can’t close your eyes during the session. It would be much easier to indulge in such auto-training.

Device diagram

A polygraph is a complex composite device consisting of several elements.

The diagram and composition of lie detector devices is as follows:

Sensors. Designed to monitor and obtain data on the psychophysiological state of the human body.
computer. computing machine, which in most cases is represented desktop computer. Records and processes received data from polygraph sensors. Subsequently, the computer converts the received information into an analog code and transmits it to the output device.
Output device. An oscilloscope, printer, or monitor screen is used as such a device. These devices display the information received by the polygraph sensors on a diagram (polygram).

The period between the moments when data is received by the sensors and displayed on the diagram lasts ~600 ms (0.6 s); in fact, data on the state of the body is displayed in real mode.

Based on the results of analyzing the information on the diagram, the specialist makes a conclusion whether the answer of the person taking the polygraph test is true or false.

Oscillograms

With the help of sensors, everything is recorded and displayed on a computer oscilloscope.

Regardless of a person’s desire, the reactions of his body give out all the truthful information. In this case, the facial expression may remain unchanged, the person may behave at ease, smile, assert, and give absolutely no indication that he is lying, however, he is unable to control the physiological reactions of the body. Moreover, they cannot be dulled even by taking super-strong doses of sedatives, a state of sleep or hypnosis, as well as a complete absence of fear or anxiety.

The inability to consciously manage and control the reactions occurring in the body, their close connection with current information stored in memory, makes the method of surveys using a lie detector scientifically sound. This method is recognized as reliable and effective in identifying information hidden by a person in many countries around the world.

How the polygraph works

The principle of operation of a lie detector is based on the detection of microstress.

During the test, many sensors are attached to the human body in places where changes in blood pressure and breathing can be easily detected. The subject is then asked specially designed questions.

When a person gives a false answer, a reflex is triggered subconsciously, as a result of which blood pressure and breathing change. The subject becomes unable to control and restrain the body’s escalating physiological reactions.

The work of the polygraph is based on identifying and recording microstress in a person. There are many sensors attached to the human body that record sudden changes in the body's response. Sensors are attached to places in the body where changes in the psychophysiological state of the body are more clearly detected.

Key indicators observed by polygraph sensors:

blood pressure;
breathing rhythm;
increased heart rate;
sweating

When all the sensors are installed, the person takes a test consisting of many questions.

For a high-quality polygraph test with a guaranteed result, the following conditions must be met:

No noise or sudden movements. Third-party activity distracts the person being tested by a polygraph, which affects physiological changes in the body, and therefore the sensor readings.
Simplicity of questions. Basically, questions are asked with the answer options “yes” or “no”. More complex questions prompt a person to think more, which also leads to changes in the body.
No amnesia. If memory of an event or subject about which the question is asked is lost, the polygraph result is invalid. If a person was a witness or participant in a situation, but does not remember anything about it, regardless of the answer of the person being tested, the required reaction of the body will not follow.

In the event of a knowingly false answer on the part of the person being tested, an unconditioned reflex is triggered at a subconscious level, which cannot be consciously controlled or prevented before it occurs. The resulting reflex, in turn, creates a microreaction of the body, which is reflected in changes in the psychophysiological state.

Even knowing how a polygraph works, it is impossible to deceive it, since the reason for revealing the truth is not in the lie detector, but in the functioning of the human brain - the detector only records the body’s reaction.

The sensor readings are transmitted to a computer, which converts the digital data into analog code, and then sends it to the output device.

Based on the results of the polygram analysis, a polygraph examiner with knowledge of the operation of a lie detector reports the manifestation of “truth” or “lie” on the part of the person being questioned. In this case, a person’s reaction may look completely calm, without changing his facial expression or averting his eyes; the interrogated person may not change his mood and calmly assert the truth on his part. However, it is impossible to control or restrain the physiological abilities of the brain.

The brain is not capable of deceiving itself and, regardless of a person’s desire or external factors, reproduces various reflexes during truth and deception. The impossibility of conscious control of reactions and processes within the body, as well as their close dependence on current information stored in memory, gave scientific justification and recognition to the polygraph testing method.

Interview with a polygraph examiner

During the interview of the subject, the device clearly records changes in all physiological parameters that occur in the human body when he answers. Then, based on the reactions received, the specialist determines which of the questions the respondent gave a false answer to.

To conduct testing, it is necessary to obtain written consent of the established form from the suspect (victim, witness). But since the data obtained are probabilistic in nature, they cannot be taken into account by the court as direct evidence of guilt or innocence.

Video: How a lie detector works

The relevance of the use of the polygraph

The lie detector is used in many areas, which is not surprising, since polygraph testing in present moment the only way to verify the truth of a person's words.

The polygraph is used in the following cases:

Checking the company's staff. Before making a decision to hire a new employee, serious corporations carry out a set of measures with him, including a lie detector test. A polygraph helps to find out in advance a person’s intentions and the purpose of employment, which is objective from a security point of view.
Crime investigation. A lie detector helps to establish the guilt of a suspect in committing a crime. We especially use it in situations where a person’s guilt in committing a crime is obvious, but for bureaucratic reasons it is impossible to bring charges against him.
Special cases. Lie detectors have also widely proven themselves to be useful in finding out the truth in individual cases, for example, when it is necessary to check the fidelity of a spouse. Today, in many countries, private companies offer human testing services using a lie detector.

Factors affecting the test result

There are four main reasons why the results of a lie detector test are considered biased:

Venue.
The test subject's body should not be distracted by external situations and phenomena not related to the test.
Time.
Based on the results of many tests, over ten years of observation, polygraph examiners have determined that the most favorable period of the day for taking a polygraph test is from morning to lunch.
Number of checks per day.
It is recommended no more than three checks by one polygraph examiner.
Psychotropic effects or alcohol/drug intoxication.
It is similar to the first reason, with the difference of a stronger impact on the psyche. Even if it is possible to test a person in the above-mentioned condition, the test results left by the polygraph on the polygram will be different.
The results of testing a person in a state of passion are different from the results of a sober person due to a more inhibited reaction of consciousness in the first. Such results cannot be analyzed even by experienced polygraph examiners and are considered irrelevant.
And, by the way, during the New Year holidays, the polygraph and polygraph examiners do not work the same way as everyone else.) Do not try to test someone on these days.

In some Western countries that use lie detectors in legal matters, violation of any of the above points may lead to the cancellation of the test results and invalidate them.

Check results

According to statistics, conclusions drawn on the basis of a polygraph are of very high reliability (80–90%).

When the tactics of using a lie detector accurately implement the principle of selective influence, all conclusions turn out to be reliable. In addition to the image or word, the actions of the investigator and the person or object during its presentation for delay can also have such an impact. All this indicates the breadth of tactical coverage of situations in which a polygraph can be used.

The polygraph works when there is a subject and sensors that are attached to it. Afterwards, a record is made, all indicators are recorded, significant points are compared with insignificant ones. Then, based on all this, appropriate conclusions are drawn.

There are some difficulties in working with a polygraph. They consist in the fact that the person being tested is placed in unusual conditions.

The whole process resembles a medical examination, which causes the subject to become agitated. A so-called situational reflex arises, which the polygraph examiner needs to remove. To do this, they try to bring the test closer to natural conditions. Sometimes, specialists working with a polygraph try to make it so that there is no need to install sensors, and the person being tested does not even imagine that he is being tested at all.

How a polygraph works: briefly

Surely everyone has heard about lie detectors used in police investigations. But sometimes those people who get a job have to undergo a similar polygraph test. new job(for example, some government jobs that require the results of a lie detector test from the FBI or CIA). The main purpose of a polygraph is to see whether a person is lying when answering certain questions or telling the truth.

When a person takes a polygraph test, 4 to 6 sensors are attached to his body. A lie detector is a machine that records multiple (“POLY-”) sensor signals on moving paper (“-GRAPH”).

Polygraph sensors usually record:

breathing rate;
pulse;
blood pressure;
sweating

Sometimes the polygraph also records data such as reactions and movements of the arms and legs.

When a polygraph test begins, the examiner asks three or four simple questions to establish signal standards. Then real questions are asked to test the detector. During the interrogation process, all signals coming from sensors attached to the body are recorded on moving paper.

Before the test begins and after its completion, a polygraph examiner looks at the graphs and sees the nature of the changes important indicators as a result questions asked. Most often, significant changes (such as increased heart rate, increased blood pressure, increased sweating) indicate that a person is lying.

When a trained professional uses a polygraph, he can detect lies with high accuracy. However, due to the fact that the expert's interpretation is largely subjective, and people react to lies differently, a polygraph test is far from the most perfect method.

How to fool a lie detector

As already mentioned, the polygraph is actually impossible to deceive: it only registers changes, while the changes themselves to a false answer occur in the human body, caused by the unconditioned reflexes of the central nervous system.

And yet, is it possible to hide a lie? Theoretically, yes, such a possibility exists. To conceal a lie, it is necessary to control and anticipate unconditioned reflexes even before they arise. Brain ordinary person is not capable of this, which was confirmed every time they tried to deceive the polygraph. The outcome of such attempts was a slight deviation in the test subject’s body parameters, however big picture The results did not differ from the results of tests in which the subject did not attempt to deceive.

Control of unconditioned reflexes is comparable to supernatural abilities. And such people really exist, but there are only a few of them in the whole world, and the chance of meeting a person with supernatural abilities is equal to the chance of becoming the mayor of a large city to the common man. These cases are unique and, if individual people have hidden abilities, their brain works differently, which is reflected in the test readings. In such cases, a lie detector test is recognized as to a greater extent irrelevant than reliable.

The prototype of the modern polygraph was developed in the 1920s by John Larson, a California police officer. The device he created provided simultaneous recording of blood pressure, pulse and respiration. With the help of this device, a large number of checks were carried out on persons suspected of criminal offenses.

Larson called his instrument the "polygraph", borrowing the name from John Hawkins, who coined the term in 1804. This was the name of the machine he invented for creating exact copies of handwritten texts. The name “polygraph” comes from two Greek words – “poly” (many) and “grapho” (write). This machine was used by many in the 19th century, including Thomas Jefferson, the third President of the United States and author of the Declaration of Independence, but it was John Larson who first applied the word “polygraph” to a lie detection device. Subsequently, this term became firmly established.

Where is the polygraph used?

How does a lie detector work?

They may not be in your favor:

the magnitude of the skin reaction increases;
the pulse slows down, followed by a compensatory increase in heart rate;
holding the breath and slowing down its rhythm, followed by a compensatory increase in the rhythm and depth of breathing;
changes in inhalation/exhalation time, inhalation pause and exhalation pause;
increased muscle tremors

There are also trap questions regarding the details of what happened (for example, theft). They are unknown to the innocent, but will cause a strong reaction to those involved in the crime. Often the question lists key words and facts. “What did you take from the safe? Mobile phone? Gun? A pack of condoms? A bunch of keys? “How long has it been since you last used drugs? Week? Month? Year? Five years? “Do you like to drink alone? In the company? In the morning? In the evenings? For days on end? “What bribe did you receive? One hundred? Two hundred? Three hundred? Five hundred thousand? As you approach the correct answer, signs of anxiety increase, and then relax as you move away from it. Although outwardly it may not be noticeable to a person.