The FBI teaches you lie detection, people reading and intelligence skills

Chapter 34 Three major issues to pay attention to in lie detection

In the above introduction to polygraphs, we have learned that polygraphs are not perfect.In order to improve the test accuracy of polygraph and receive better test results, what problems should be paid attention to in the specific application?

As a polygrapher, one must not only make judgments based on various behavioral traces in daily interactions, but also make judgments based on recorded charts under polygraph test conditions, but it is inevitable that mistakes will not be made.This kind of mistake is nothing more than two types. One is not believing the truth, that is, mistaking the truth told by the other party as a lie; the other is believing a lie, that is, mistaking the lie told by the other party as the truth.These two types of mistakes may cause serious consequences, or cause losses and dangers to oneself, or doubts and injuries to the other party.Therefore, it is extremely necessary to analyze its causes and prevent the occurrence of these two types of errors.

There are many reasons for making mistakes in polygraph detection. As far as judgments based on behavioral traces and polygraph results are concerned, the following three factors are mainly involved.

§§§The first section unknown factors can easily lead you to detours

Generally speaking, almost every polygraph examiner has certain experience on how to detect signs of lying from facial expressions, tone of voice, speech, and body movements, and forms his own standard for judging lies based on this experience.However, in the actual process of polygraph detection, most people often fail to consider that the standard of lying marks is not exactly the same for everyone, but is very complicated. The judgment standard of polygraphers may only apply to some people and not another group of people.

As far as the types of mistakes that the lie detectors believe in the lie during the polygraph detection process, there is no trace of lying that will definitely be revealed, so the fact that the lie detector does not find the trace of lying does not mean that the other party is honest, because many experienced lies Those who are extremely good at self-control.

As far as the type of error of not believing the truth in the lie detection process is concerned, even if the other party shows signs of lying, it may be due to reasons other than lying.For example, some people's behaviors have obvious personality characteristics, or their expressions are obviously different from others. The specific performance is that they often pause in their speech, sometimes for a long time, sometimes for a short time; Sexual gestures; don't like to speak straightforwardly, always beat around the bush; no matter how he feels in his heart, his face often shows nervousness; his expression is asymmetrical, etc.Because these performances are different from ordinary people, the judgment standards that are applicable to most people are not applicable to them, so that it often causes the illusion of lie detectors.

To reduce errors due to unknown factors, a lie detector must know the other party's usual behavior in order to compare it with his behavior when he is suspected.When the polygrapher is familiar with the daily behavior of the other party, he may find a more objective comparison standard.However, slips of the tongue, emotional "grand remarks" and mistakes in symbolic actions are usually exceptions. They are not the same as other lying signs and are not subject to the limitations of unknown factors. Is it the same in normal times, or in other words, you can make a judgment that the other party is lying without any specific comparison standard.

§§§Second Preconceptions distort your judgment

Preconceived notions can skew a polygrapher's judgment.If a polygrapher suspects or thinks that the subject has done something bad in advance, then what he thinks when he is detecting a lie is to prove his suspicion, so that he often chooses and explains those behaviors that conform to his existing concepts intentionally or unintentionally. traces, and even unknowingly distort objective information to cater to subjective ideas.In this way, it is very easy to make the mistake of not believing the truth.

In ancient my country, there was a story of "the suspect stole the axe".

A farmer lost an ax and suspected that the neighbor's son had stolen it, so he watched his every move carefully, and it turned out that he looked like a "guilty thief".Later, the farmer found the ax and looked at the neighbor's son again, and felt that his words and deeds were no different from normal people.Here, the behavior of the neighbor's son has not changed, what has changed is only the subjective perception of the farmer before and after he found the axe.

The FBI pointed out that the farmer first had the concept or prejudice of "suspecting someone who stole the axe", so he looked at the neighbor's son with a "weird" perspective, and it seemed that he could find "doubtful points" that could prove his suspicion everywhere.After finding the axe, the farmer's skepticism or prejudice no longer exists, so those "doubts" are no longer visible.It can be seen that the doubts on the neighbor's son are "projected" by the doubts in the farmer's mind.

People have a certain psychological tendency when they know things, and they always choose to accept those things that are in line with their own existing concepts intentionally or unconsciously, while ignoring or even rejecting those things that are in line with their own existing concepts. thing.Even for the same thing, different people will come to different understandings or interpretations due to their different existing concepts.Polygraphs are no exception.In many cases, because the polygrapher himself is in the state of mind of being suspected of being deceived, he will often use deception as a reasonable explanation for the things that confuse him.Especially those who are suspicious by nature.

A staff member who has worked in the US Central Intelligence Agency for more than 20 years once wrote: "It is satisfying to regard deception as the cause of many phenomena. This is because this explanation is very suitable and very reasonable. When we cannot find other When explained, the explanation is both simple and realistic. In fact, the phenomenon that needs to be explained is either caused by error, or it is abnormal, or it is due to factors that we do not yet know. Out of intelligence Officers tend to be very sensitive and always think that someone is deceiving. And once he exposes the lie, people will credit him, so many intelligence personnel use deception as the most convenient explanation. Because any piece of evidence can be used To prove that someone is deceiving, it is so easy to use deception as the cause. We can even say that if we consider deception as a possible cause, we will almost certainly be able to confirm the hypothesis."

Phenomena like this do not exist only within the scope of intelligence work or police work. In daily life, many people who are confused and suspicious may think that others are deceiving themselves. Something that confuses you.And, once this prejudice has developed, he will turn a blind eye to it, even if there is evidence that it is wrong.Strong suspicions may also lead to abnormal psychology.

Polygraph testers should understand that they may have preconceived prejudices. Only when they are aware of this can they be more cautious when analyzing polygraph situations.

§§§ Section [-] Othello-style mistakes you will never regret
The "Othello error" is based on Shakespeare's play "Othello". This error can easily lead to not believing the truth. Liars look very much alike.

For example, the fear of being wronged when a truth-teller knows he is being suspected may be mistaken for a liar's fear of being caught.And some people have a sense of guilt because of other things, these feelings of guilt have not been relieved, and once they are suspected later, this sense of guilt will reappear, so that the polygraph examiner mistakenly thinks that it is caused by lying.

In Shakespeare's play "Othello", Othello rebukes Desdemona for falling in love with Cassio because of Iago's instigation, and asks her to confess it.Desdemona asks Othello to confront Cassio to prove her innocence, but Othello tells her that he has killed Cassio.At this moment, Desdemona understood that she could no longer prove her innocence.

Desdemona was originally disturbed by fear, but Othello thought she was so because she heard that her "lover" was killed, so she believed her infidelity even more.In fact, Desdemona is innocent. The reason why she has emotional disturbance is firstly because Othello does not trust her, she is disappointed and sad; secondly, because Cassio is killed and she proves her innocence. In the end she felt hopeless when her hopes were dashed; thirdly, because she knew that Othello was going to kill her, which made her feel even more horrified.The reason why she was crying was definitely not because of "the death of her lover", but because of her own unfortunate fate, because of an irreparable ending.

In the process of lie detection, an innocent person who is suspected is as likely to have nervous feelings and emotional expressions as a suspected guilty person. If these signs are only analyzed as clues to lying, without considering the cause The difference between them may often cause the mistake of not believing the truth.

Jack's neighbor Anna is raped and killed, and Jack becomes a suspect because many things point to Jack as a suspect: Jack doesn't show up for work the day after the murder; When he got home he heard him say to his wife, "I didn't want to do that, but there's no other way."

Jack later explained that it wasn't about murder but drinking, but no one believed his explanation.The policeman asked Jack what the stain was on his car seat, and he said it was there when he bought it.But later, when the police investigated further, he admitted that he had lied earlier, saying that he was embarrassed to admit that he had quarreled with his wife and slapped her, causing her nose to bleed.The police repeatedly said to Jack, this proves that you are a brutal person, and it is entirely possible to kill someone!And prove that you are a liar who will definitely deny the bad things you have done.

During further interrogation, Jack admitted that he had committed a minor sexual assault when he was 12 years old, but did not hurt the other party, and has not committed it again since then.After investigation, it was found that Jack was not 12 years old at the time but 15 years old.The police emphasized that this further proves that Jack is a liar and has a history of sexual assault, so he is likely to be the murderer of Anna.

The police brought in a full-time polygraph officer Thomson.When Thomson shows up with the police, the police tell Jack that Thomson has never made a mistake on a polygraph, so don't take chances.When Jack took a polygraph test, he was faced with two sets of questions, but the test results were confusing and contradictory: When asked about the murder itself, the polygraph showed that Jack was lying when he denied guilt; When the murder weapon and how it was disposed of, the lie detector showed that Jack did not lie when he said "don't know".Thomson asked questions about the murder weapon three times, always with the same result.But after the quiz, Thomson told Jack he had failed the polygraph test.

The police had long believed that Jack was the murderer, so they continued to interrogate Jack for 6 days.During the interrogation, tapes show that Jack became exhausted.Jack professed his innocence until near the end of the interrogation, protesting that he had no memory of the murder or rape, so he couldn't be the culprit.The interrogating policeman retorted that the murderer may temporarily lose his memory and may deliberately conceal it, so saying that he cannot remember the circumstances of the crime does not prove that you did not commit a crime; the police also told Jack that his wife said he knew he killed Anna... Finally Jack confessed.However, a few days later, Jack retracted his confession, and Jack's wife also stated that she never told the police that "she knew Jack killed Anna."It was not until seven months later that the real murderer was caught for committing another rape and murder case, and Jack was freed.

The police investigating Jack made an "Othello error".The policemen, like Othello, did spot a strong emotional reaction in the suspect, but misjudged the cause of his emotional reaction.Here's the question: Does Jack's strong emotional response to murder questions when he takes a polygraph test confirm that he's the murderer?Could there be other reasons for Jack to have a strong emotional reaction to it?One of the reasons for Jack's strong emotional response to questions about the murder is his fear that the police won't believe him.Jack was involved in a murder case, which was a matter of life and death to him. If he could not prove his innocence, the punishment that followed would be extremely severe.Therefore, even though Jack knew he was innocent, he was still afraid.What scares Jack even more is that the police are clearly prejudiced against him and openly believe that he is the murderer.This made Jack even more concerned that the police had put him on a polygraph test just to confirm their preconceptions.

Jack's emotional distress during the polygraph test was also related to his feelings of shame or guilt for some of his mistakes.Two of the incidents were detected by the police: one was beating his wife so that the car seat stained with his wife's nosebleeds became physical evidence that the police suspected; the other was a crime of sexual assault in his youth.Jack wanted to conceal or distort these two things at first, fearing that the police would link these two things with the murder case, but under interrogation by the police, he finally had to confess the truth, which made Jack feel even more ashamed and responsible. guilt.

And the police linked the two things that Jack did and the different reactions before and after with the murder case, which inevitably increased his psychological burden.In addition, there is one more thing that the police do not know.When answering the reporter's question "why he failed the lie detector test" after he was released from prison, Jack gave another reason: "On the night Anna was murdered, Anna's husband came home from get off work in the middle of the night and saw his wife's body." , he ran to Jack’s house and asked him to call the police; when Jack went to Anna’s house with the police, he looked at Anna’s naked body several times with lustful eyes. Afterwards, Jack felt that his behavior was very immoral, and he felt As if committing a crime.Therefore, when he was asked about the murder during the polygraph test, Jack always felt ashamed and guilty, and he had to hide it, so that he showed many signs of lying.

(End of this chapter)