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Polygraph principle body is betraying you

Traceability: The history of polygraphs from pulse selection can be traced back to 300 BC. The Greek physician Erasisistrautus first noticed the use of pulse selection to detect lies.

He took the pulse for Syrian prince Arterx. It was rumored that the prince fell in love with the young and beautiful stepmother Sirardina Ais. The prince became thin and emaciated, and the king thought the prince had a terrible disease.

Elasi Stuart took the pulse for him while entering the queen’s virtues with the prince, and then told the king that the prince was not sick, but tried to hide his deep affection for the queen.

  As early as 1895, Italian criminologist Rombroso was the first to use the original “polygraph” for criminal investigations.

The “polygraph” he applied was called “hydraulic pulse recorder”.

  In 1921, Larson, California ‘s Berkeley Police Department assembled a portable device that could record changes in blood pressure, pulse amplitude, and breathing patterns.


Larson did many polygraph tests from 1921 to 1925.

His instrument is now placed at the Smith Institute in Washington, DC.

In the 1930s, Larson’s assistant Keele developed a new Keler polygraph, and the skin resistance was added to the Keler polygraph as a third channel.

This is the first polygraph that can combine breathing, skin resistance, and cardiac response in a comparison unit, and has applied for a patent. It is widely used in the US military and police.

This is the first polygraph in the world.

  Today’s polygraph and ancient pulse tests are the same, but they are more complex, more accurate, and more systematic.

  Focus: What does a polygraph measure?

  Lie detection actually measures people’s psychological changes through three main parameters: skin resistance, breathing wave and pulse wave (blood pressure).

  Skin resistance is the most effective and sensitive physiological parameter that reflects the excitability changes of human sympathetic nerves. It understands the changes of human psychological tension by measuring the degree of sweating in the palm of the hand.

The response is large, the sensitivity is high, and it is not easy to be directly inhibited by the cerebral cortex consciousness. It is the most widely used and widely recognized psychological test index in the world.

  Respiratory waves are one of the important physiological indicators that reflect the psychological changes of a person. When a person is nervous, the breathing will subconsciously change locally, such as deep breathing, holding your breath, or increasing or slowing your breathing rhythm.

When the excitability of the cerebral cortex changes, it will inevitably affect the change of the respiratory wave, and this change is often unconscious.

  Pulse wave (blood pressure), neurons related to cardiovascular activity are widely distributed in the central nervous system. In the regulation of cardiovascular activity, the hypothalamus is a very important integration site. It is a higher-level site that integrates various internal organ functions.Plays an important role in emotional reactions such as anger and fear.

Therefore, changes in psychological stress and mood will cause changes in cardiovascular activity.

In fact, when people are nervous, the pulse output of the heart increases, and the heart rhythm speeds up, causing the systolic pressure of the pulse wave to rise.

In addition, a person’s nervousness affects the range of the length of the blood circulation, which increases the longer length, thereby increasing the diastolic blood pressure of the pulse wave.

These can be clearly shown on the map.

  ”Unlike the concept given to us in film and television works, a polygraph is not testing lies, it is actually just recording real traces of psychological change.” Wu Boxin, a professor at the People’s Public Security University of China, gave the polygraph such a position.

“The principle of polygraph detection comes from a human physiological phenomenon first discovered in the 1920s.

That is, a person’s psychological response will be displayed by physiological changes in the body.

For example, if you experience something horrible, you usually feel an uncomfortable chill, unconsciously sweating, or involuntarily shaking your voice and muscles.

These physiological changes are caused by dangers that you perceive.

If someone asks you if you have committed some wrongdoing and you did, you can’t help but think about what you did in the past.

At this point, if you admit it, you will be punished, if you deny it, you are lying, putting you at risk of being exposed.

During the polygraph, the danger is that your body will betray you.

“Polygraph detection is an activity of human-computer combination. The first step of the test procedure is the design of the test question. It determines whether the test subject can accurately recognize the authenticity of the test question answer.

  Prior to the formal test, the polygrapher is to interpersonalize with the person being tested in a non-interrogation manner. He will ask questions to expand the information from the test subject.

In the pre-test personality, the polygrapher must make a clear statement to the polygraph subject, transforming thinking about the questions that will be asked during the test.

Of particular importance here is the design of the polygraph problem.

The ability of a polygrapher determines the choice of polygraph problem and whether it can be clearly stated.

This is related to whether the test subject is affirmative when answering the question, and whether it makes the test subject feel the pressure of the question.  During the test, all test questions require the test subject to carefully consider to ensure that he can answer each question with “yes” and “no”.

Throughout the test, the polygrapher will conduct three to five independent tests, each of which contains the same questions, but differs in design.

The purpose of a polygraph is to reinforce the difference between the subject’s response to the subject matter and the companion question by using some hypothetical questions.

  Then start the formal test. Blood pressure or pulse can be measured with a standard sphygmomanometer, which is basically similar to the way a doctor uses a sphygmomanometer to measure blood pressure.

The breathing method uses two straps that are tied around the upper part and the abdomen to measure the change in the stretching force caused by the breathing of the test person.

The skin resistance is reduced by GSR (Galvanic skin response), which is to place two electrodes on the skin of the person being tested (usually on two non-interconnected fingers). The person measuring is monitored and recorded by a computer polygraph systemChanges in skin resistance during a polygraph.

The polygraph’s stylus traces the psychological changes of the person on the polygraph.

Of the four curves displayed and traced on the computer screen and polygraph, two are breathing patterns, one is used to trace the GSR, and the other is the blood pressure and pulse, which is called electrocardiography.

After the polygraph is completed, the polygraph will study and analyze these four curves, and perform a polygraph lie.

  The whole polygraph process seems simple, and the real effort is concentrated in the analysis after the polygraph ends.

  Inheritance: The history of the development of psychological test in China is very short. In 1990, the National Science and Technology Achievement Exhibition was antiqued in the Beijing Exhibition Hall.In the eyes of officials of the Science and Technology Department of the Ministry of Public Security.

It turns out that the function and principle of this instrument are surprisingly similar to the “polygraph” recorded in foreign literature.

Everyone who is familiar with shooting sports knows that psychology is a very important factor in shooting competitions. It is no wonder that Tao Luna, the shooting athlete of the Sydney Olympic Games, won the gold medal first by her psychological counseling expert.

Entrusted by the National Sports Commission at that time, the Automation Research Institute developed the first (predecessor of PG-1) multi-parameter psychological tester, and a large number of shooting experts were once one of the users of this instrument.

  To this day, China’s polygraph is currently in a certain position?

The reporter interviewed Song Libo, an engineer of the Training Department of the Psychological Testing Center of the Chinese Academy of Sciences. Teacher Song told the reporter: “At present, there are only a few companies producing psychological testers in China. Only Beijing Tongfang Shenhuo United Science and Technology Development Co., Ltd., Beijing Public University Jiuding Psychological Counseling Center and the Chinese Academy of SciencesThe six units in the psychological test center are not large enough.

However, technically, although there are only a few years of development, our technical level can basically be in line with international standards. Among them, the PG series developed by the Chinese Academy of Sciences and the LY type 6 pilot test produced by Beijing Tongfang Shenhuo United Science and Technology Development Co., Ltd.Lie system, TH 6-lead polygraph system and SPS-4000 4-lead polygraph system. The TH software includes an automatic scoring system without any manual intervention.

The PGA99 psychological tester launched by Beijing Gongjiuding Psychological Counseling Center reduces external knobs and greatly improves the degree of automation.

“” But because polygraph detection is a combination of man-machine and human-oriented technology, from this perspective, it is difficult for us to reach the level of the United States and other western countries.

The key to the success of a polygraph lies in the level of the polygrapher.

In the United States, polygraph training is well established and distanced.

It takes 10 weeks of training from a polygraph school. After passing the exam, you can become a junior polygrapher. To become an advanced polygrapher, you need to continue training. It takes about 2 years.

Qualified polygraphers are very valuable. Basically, there is currently no professional system for polygraph training. There is still a large gap between the theoretical basis and the level of training.

There is no problem with the technology. The results of the polygraph are objective and real, but there will be some errors in the results of frequent analysis, which cannot be overcome in the short term.

“That’s why the polygraph can only be used as an auxiliary tool in criminal investigations. It can be used as a collection of case evidence to provide clues, not as evidence in court.

  Browsing: Polygraph behavior is abroad in the United States. Due to inaccurate instruments and insufficient training of polygraphers and other interpretations of polygraph results, the legal profession doubted the reliability of polygraph technology.

Now, courts in many states have provided that polygraph results can be used as court evidence.

The legal profession has accepted that if someone passes a polygraph test, it is said to be suspended.

If he fails the polygraph test, he will be sued in court.

Norman, United States?

Mr. Ansley collected polygraph samples from field investigations since 1980, and compared this with confessions, physical evidence, and court judgments, studied the results of 2042 cases, and even minor disputes were considered to be polygraphError, the accuracy obtained is 98%.

The American Polygraph Association’s statistics on the literature reports of six countries in the 1980s showed a total of 3030 cases. The results have been investigated and verified by interrogation. The accuracy of the polygraph is also 98%.

In the United States today, in addition to key national departments, such as the military, police, intelligence, and national security departments, polygraphs are commonly used.Polygraph technology to test employee loyalty.

Every year, more than one million people in the United States receive a polygraph.

  Except the United States, many countries are currently using polygraph technology, some are Israel, Canada, Japan and India.

  Israel, like India and other countries, has very different domestic cultures, and even so, they are widely using polygraph technology.

In Israeli criminal trials, polygraph results have not yet been accepted as court evidence, however, prosecutors may be affected by polygraph results.

In a civil trial, the results of a polygraph can be adopted as evidence in court under certain conditions.

Israel is also one of the few countries where polygraphers have the right to formal training.

  Canada is a bilingual country, and many polygraph tests are conducted in French.Canadian polygraphers have undergone basic training, and all judicial polygraphers have graduated from the Ottawa Police Academy.

Many polygraphers from the US Justice Department are also trained here.

In Canada, although polygraph results cannot be proved by court evidence, they can play a significant role in investigations.

  Polygraph results are a very important part of Japan.

In the evidence required for criminal trials, they are admissible in court.

  The Indian judiciary also makes extensive use of polygraph technology, even if it involves fifteen languages and different cultures.

In 1948, after a captain police officer completed six weeks of polygraph training in the United States, India began to apply polygraph technology.

However, the polygraph operation of the police department was suspended in 1974.

This is because the polygraph results made by the police are not generally accepted by the courts.

The court is more likely to accept someone than a police officer, and research has shown that the effectiveness of polygraph tests to protect the testee ‘s interest is between 90% and 98%.

  In fact: The problems with polygraphs in the West are skeptical about the accuracy of polygraph detection, but they have become fierce about whether human rights violations, especially large weights, have become fierce.

Polygraph technology is widely used in the United States. Private polygraph companies are everywhere, and some directly apply to the investigation of private life, including infidelity of husband and wife, homosexuality, personal possibility, etc., so some people have resisted.

There are also abuses of polygraph techniques that violate human dignity.

During Reagan’s presidency, he had asked all senior officials to pass a polygraph test, which caused a strong response.

Secretary of State Schultz strongly protested that it was distrust of him, was insulted, refused to lie, and set off the famous “Schultz incident”.

This will lead to the development of society as a trend problem of China’s polygraph.

  Although polygraph technology is highly accurate in China, it is not absolutely reliable, and errors do occur.

The error in the test may be caused by the polygrapher’s inability to properly test the subject, or the physiological data on the polygraph chart may be misread.

Mistakes are usually “wrong assertions” or “false negations.”

When an innocent object is identified as a criminal, a false identification occurs, and when a criminal is found innocent, a false negation occurs.

The case of Du Peiwu in Yunnan Province, which was once famous all over the country, and the case of Liu Minghe in Anhui Province, etc., were due to the incorrect use of psychological testing technology, which led to the wrongful identification of the suspect by the investigators, and eventually resulted in an injustice.

  In addition, for the theoretical basis of these technologies, the legal procedures in the process of use, the limits of the test subject and the testee, the production and sales of instruments and standardized industry standards, the qualification and training of testers, etc.According to legal regulations, the current technology has gradually become distorted and chaotic.

  The most important point is professional training for polygraphers.

In fact, psychological testing technology is a practical technology that combines psychology, biology, medicine, electronics and other disciplines.

In developed countries such as the United States, the overall strict operating procedures prescribed by law for psychological test experiments. For practitioners, they can only conduct the operation experiments of this technology after they have obtained qualifications through distance learning and training at a polygraph school.
Under normal circumstances, only the Psychological Testing Center of the People’s Public Security University of China trains a small number of postgraduates and professional and technical talents in psychological testing every year. In addition, there is no further training institute and no corresponding employees.Qualification assessment and certification body.