For many centuries, people have tried in various ways to identify the truth and find out when a person is lying. In ancient China, the suspect filled his mouth with rice grains, which were examined after the accusation was announced: if the suspect is worried, his throat becomes dry, which means the grains will be dry and his guilt is undeniable. Today, to identify lies or find the truth, they use other, more advanced devices - lie detectors. From this material you will learn how the polygraph works, what it reacts to. What affects the accuracy of the test. Is it possible to deceive him?
How did the lie detector come about?
In ancient China, during the announcement of charges, the suspect was forced to take a mouthful of rice. If the grains remained dry after extraction, then the guilt was considered proven.
In India, during the “investigation”, he was given key words associated with the crime. Having heard them, the suspect had to immediately say any word that came to mind and kick the gong. At moments when the subject was lying, the gong was struck more powerfully.
At the end of the 19th century, the Italian physiologist Angelo Moss, while showing fear-inducing pictures to a patient, discovered that the subject’s heart rate increased. For these purposes, he used a plethysmograph , a device that helped determine the pulse rate.
William Marston is considered to be the true inventor of the polygraph . He devoted his life to the study of human behavior and the connection between humans and physiological processes. The topic of Marston's doctorate was the development of a test that could detect lies by measuring changes in systolic blood pressure.
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. Since the sensors that record the electrical conductivity of the skin are worn on the fingers, their tips can be treated with agents that block the sweat glands. 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.
What is a polygraph?
Nowadays, a polygraph or “lie detector” is a whole complex of devices consisting of:
- laptop with necessary software
- 5 – 8 sensors recording various physiological indicators
- in fact, the polygraph examiner himself, a person without whom it would be impossible to understand where the line between truth and lies is.
It is important to understand that the polygraph itself does not show anything . That is, he does not say: “This is true,” but here the person lied. It only measures biological changes in the human body.
But the answers themselves are given by a specialist polygraph examiner. And the results depend on how professional this person is.
Safety of polygraph testing.
Many people are interested in how a polygraph is performed. This procedure is absolutely safe and harmless to human health: there are no physical effects on the body. Any of the sensors is absolutely passive, and the feeling of a polygraph test can be compared to an ECG.
Psychologically, the test can be stressful. Many people experience a little anxiety before and during the test. Anyone who is involved in something and is afraid of being exposed will always be afraid. An innocent person is afraid of false accusations. The ward is worried that the polygraph examiner and the customer may become aware of any socially disapproved actions or intentions that took place in the past. Plus, individual questions can cause offense or resentment. Therefore, you need to be prepared for possible stress or unpleasant emotions. The degree of excitement before testing is always recorded and must be taken into account during the test, i.e. this will not affect the final result.
How does a polygraph work?
1. Installation of sensors. The subject is asked to attach several sensors. Each of them records a certain indicator. During testing, the polygraph comprehensively controls:
- chest breathing
- diaphragmatic breathing
- skin conductivity
- heartbeat
- blood supply in peripheral vessels
- arterial pressure
- foot mat and tremor sensors
2. Brief instructions from a specialist. Before the test begins, the polygraph examiner tells you how to answer the questions.
3. Setting up and calibrating the device. To calibrate the detector, questions are asked to which the psychologist knows exactly the answers. They may ask something like: “Your name is Dmitry?”, “Are you 38 years old?” and so on.
4. Analysis of answers. Verdict. After 100 - 300 questions, the polygraph examiner begins to study the resulting graphs and draws conclusions.
How to prepare for testing
If the person has nothing to hide, then significant preparation will not be required, although the person's simple nervousness may skew the indicators. A number of rules apply to quality preparation:
- Before the test, good sleep and rest are recommended.
- You should not take medications that can make your emotional background unstable.
- It takes concentration and composure.
- You should not reason during testing.
- Before testing, you should not drink a lot of liquid, eat a lot of food, or, conversely, torture yourself with hunger.
If a person feels unwell, then they should inform the polygraph examiner and ask to reschedule the study.
Can you trust a polygraph?
A good polygraph examiner is the key to a successful and reliable test for truth and lies. This person must have good psychological training. Why? Yes, because he must know how to put pressure on a patient.
Using a test set of questions, a polygraph examiner determines how a particular person physiologically reacts to truth and lies. Some people's breathing quickens, but their pulse remains unchanged, while for others it's the opposite.
For example, during a test the same question may be asked several times. At the same time, its semantic essence remains the same, but the subject’s brain at this moment reacts to it differently.
The polygraph examiner’s task is to respond correctly to such surges in blood pressure and pulse. That is, the exact result essentially depends on one person.
But if he is a professional, then the percentage of test reliability according to statistics is about 95 - 98% .
Principle of operation
How does the polygraph work and what does it react to?
The basic principle of the polygraph is based on the belief that the more important the question asked is for the subject, the stronger his physiological reactions will be .
The test procedure on the detector is as follows. All issues that will be raised during the process are discussed in advance with the object being inspected. This occurs immediately before the verification procedure.
This is done so that there is no vague reaction that may appear if the question is unexpected.
Because of this, the subject will hesitate, may become nervous or surprised - all this will distort the results of the test, since the polygraph will count such an answer as “lie”.
The test itself takes on average 1.5-2 hours. The subject is read the questions and given two possible answers: “yes” or “no.” The polygraph records the subject's reaction to it within 15-20 seconds after the question is voiced. The following reactions may indicate a lie:
- slow heart rate;
- increased skin reaction;
- heartbeat accelerates;
- the time of inhalation or exhalation changes;
- breathing rhythm changes;
- muscle tremors increase.
In addition, in order to disorient the subject being tested and destroy his defensive reaction, some psychological influence is applied.
The expert changes the wording of the question and repeats the same question several times.
He may even ask you to answer “yes” to all questions, including those to which you previously answered “no.”
Also during the survey, neutral questions are asked , for example: “Is it Wednesday today?”, “Is it morning?”, “Are you sitting on a chair?” etc. They are necessary to make a person’s physiological reactions to lies more noticeable.
Control questions are also asked , for example: “Have you ever taken or appropriated something that did not belong to you?”
Every person has committed such actions at least once in his life, so they cause a reaction even in an innocent person. At the same time, they will cause a greater reaction in the innocent.
Where is a lie detector used?
Recently, the polygraph began to be used when applying for jobs. True, the number of potential applicants for employment in such companies drops sharply after candidates learn about the need to take a lie detector test.
But the most popular place to use lie detectors is:
- law enforcement agencies (for the purpose of interrogating suspects) - government agencies
According to statistics in Russia, almost every tenth company offers to take a lie detector test.
Of course, you can refuse such a check. True, the chances of finding a job after such a decision drop sharply. After all, you are clearly hiding something from your future superiors.
Acting
If a person is a professional actor, well acquainted with the technique of implanting himself in 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.
Why is the polygraph not used to solve crimes?
It would seem that if a polygraph allows you to get answers to any questions, making sure it’s true or false, why aren’t lie detectors used everywhere when investigating crimes?
The fact is that today the polygraph is positioned only as indirect evidence of guilt. And all because of such a thing as the Brokaw Trap .
This is a special case in human psychology, which appeared in terminology in 1985.
Its essence is that for some people, physiological manifestations of deception may turn out to be part of their normal behavior. A polygraph examiner can assess the behavior of such people incorrectly, thereby, to use the slang of representatives of this profession, “fall into the Brokaw trap.”
Given this, it is impossible to use the polygraph as the only reliable tool for solving crimes.
This is because a person can answer many rather complex questions with excitement. That is, if you are suspected of something that you did not do, but you are threatened with 10 - 15 years in prison, it is unlikely that when tested on a polygraph, the question “Are you guilty of a crime?” you will think directly about the answer to the question.
You will be tormented by all sorts of thoughts: about the future, about the family, about the consequences, but not about the fact that you are not involved in this. All this is recorded by a polygraph and it is possible to distinguish such nervous excitement from a true lie only after repeated repetitions of the question and scrupulous testing.
The qualifications of a polygraph examiner are most important here. This means that the sentence, in essence, will depend on one person. His mistake may cost the fate of another.
How to behave during testing.
Before the testing itself, every person has a reasonable question: how to pass a polygraph test? Sometimes before the test itself, the feeling of anxiety gives way to panic. No need to worry. First of all, calm down, make yourself as comfortable as possible in the chair. If something worries you or you feel discomfort, tell the polygraph examiner. During the test, you do not need to make unnecessary movements, you need to breathe at your usual rhythm, you need to look only forward. Answer any questions simply: “YES” or “NO.” Listen to every word of the specialist, listen to everything to the end. At the same time, do not analyze the behavior of the polygraph examiner. This will start to distract you and increase your stress level, which will ultimately lead to errors in the final results. At the same time, make sure that the specialist maintains an interval between each question - it should be approximately 10 seconds.
Is it possible to fool a polygraph?
As they say, nothing is impossible. By spending a couple of months learning and honing techniques for bypassing a polygraph, you can train your body so that the lie detector will mislead the polygraph examiner.
The essence of bypassing a polygraph is to learn to control your emotional state. And you will have to do this not only during testing, but also in everyday life. Regularly and methodically, you will have to control your emotions.
During the test you may be asked hundreds of different questions. It will take months to control yourself. Ahead lies a long period of mastering the practices of meditation and pacification of one’s own emotions.
However, deceive the polygraph in another way:
- you have a natural gift - you are a professional actor, capable of acting authentically and believing in what you play - you have a very developed sense of self-control
Finally, if you are a psychopath and do not adequately perceive reality. People suffering from nervous and mental disorders find it easy to deceive a polygraph. They simply do not understand where is real and where is fictional.
In fact, to bypass the polygraph you only need one thing - to believe that you are telling the real truth (even if it is a lie) and to be calm as a boa constrictor. But people spend years training these qualities.
And besides, do you need such a skill? If you have something to hide from yourself, then maybe you just need to reconsider your worldview?
Basic methods of preparation
It is important to prepare yourself correctly for a polygraph examination. Remember that company employees will ask you uncomfortable questions, especially if you need to create a psychological portrait of a person. So you might be asked, “Did you steal from your parents as a child?” or “Have you ever wanted to kill a loved one?” Sometimes these questions may not even be relevant to your case, but they help test how your body reacts to such assumptions. It is worth understanding that you are not suspected of anything, and the employees conducting the examination themselves have nothing against you, do not want to offend you or suspect you of anything.
Other effective ways to prepare include:
- It is better to go for examination with fresh strength. Go to bed early the night before and try not to worry and get enough sleep. A tired person has a more excitable nervous system, which can affect the accuracy of recognizing the truthfulness of your answers. It is also worth remembering that the procedure itself can last several hours and if you do not get enough sleep, it will simply be physically difficult to be under tension throughout the entire time;
- Pay attention to preparation the day before the examination. It is important not to take any sedatives, much less alcohol or psychotropic substances. It also puts your nervous system into an excitable state. Side effects from taking such substances may also be seen as attempts to deceive the machine or obtain distorted results of the study so that it can be challenged;
- Visit the toilet before the procedure. It is important to go to the test with an empty bladder to ensure that the device readings are correct and without distortion. Holding back urination could also potentially be seen as a potential attempt to fool a lie detector test;
- You need to wash your hands before visiting a polygraph examiner. Contaminants can interfere with your body's response.
Drawing conclusions
1. The effectiveness of the polygraph has been proven - it really allows you to bring the average person to clean water.
2. The polygraph is rarely used in forensic science due to the presence of the human factor. The fate of a person during testing is in the hands of a polygraph examiner. But he could be wrong.
3. You can fool a polygraph, but only after months of practice and direct, regular access to the device.
4. Lie detectors are already actively used not only in law enforcement agencies, but also when applying for jobs in many reputable companies.
5. The polygraph itself does not answer questions and does not give a clear picture of where the truth is and where the lies are. He only reads physiological indicators, and the answer is given by a trained specialist - a polygraph examiner. He analyzes multiple graphs and dynamics of electromagnetic pulses taken using polygraph sensors.
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