Home Page > Reading Room
Despite a warning from the National Academy of Sciences that polygraph testing is unreliable, the U.S. intelligence community continues to rely on polygraphs to assess the credibility of prisoners, agents, informants, and its own employees. now presents strong evidence that America's Islamist adversaries understand full well that polygraphy is a sham, and that they have an idea of how to fool the lie detector.

The following is a rough English translation of "Usturah jahaz kashf al-kidhb" (The Myth of the Lie Detector), an article published in the Iraqi jihadist Al-Fath magazine, No. 1, Dhu al-Qa'dah 1425 (December 2004), pp. 19-23. The article has also been reproduced on the Al-Qaeda affiliated website Although not referenced, it is clear that's e-book, The Lie Behind the Lie Detector was a primary source for this article. Images of the original Arabic pages have been added for reference purposes below the translation. To discuss this article, see the message board thread, Al-Qaeda Has Read The Lie Behind the Lie Detector.

Be on your guard...

The Myth of the Lie Detector

The lie detector or polygraph is in reality a method used by the enemies of God in their prison cells and detention camps to put psychological pressure on the mujahidin during the interrogation of those they take prisoner in order to collect as much intelligence information as possible. Security and intelligence agencies – especially Western ones – have spun a halo of lies around it to obfuscate the truth, so that many think that a person being tested will only be saved by the truth, and nothing but the truth!

So what is the truth about this device? And can it detect lies or not?

The device is actually composed of a group of devices whose purpose is to measure physiological changes that occur in the body [of the person] to which it is attached. It measures heart rate, blood pressure, respiration rate, and degree of perspiration.

These rates are measured and recorded at different stages of the interrogation. It is well known that these rates change in response to pressure and the psychological state the mujahid is experiencing, such as anxiety or relaxation, security or fear, or other psychological states.

At the beginning of the interrogation, the interrogator strives to establish the natural level or rate of the mujahid's physiological variables so that later, when the mujahid answers questions during the interrogation, he can compare the results recorded by the device with those recorded at the beginning during what are known as “control questions” that are considered to be the mujahid's natural level.

The control questions are a group of questions that the interrogator asks the mujahid and the answers to which are known by both parties. The interrogator presents these questions to the mujahid and asks him to answer them, and meanwhile, the device records what are considered the natural heart, blood pressure, breathing, and perspiration rates, which will be compared with those that will be recorded during the real interrogation questions. If the mujahid is upset during when answering the interrogation questions, these physiological rates will change, and that will be considered an indication that he is lying.

If you know this, my brother mujahid, then you know that the “control questions” are among the most important stages the mujahid undergoes during interrogation with this device, and he must know how to deal with them as will be explained shortly.

The first thing that must sink into the mujahid's head is that the aforementioned physiological changes can occur for reasons other than lying such as nervousness, anger, sadness, embarrassment, fear, relaxation, and so forth. Cold, headache, and constipation may also cause changes in them. All this greatly diminishes the importance of the test results.

And don't suppose that experts can tell the difference between changes caused by lying and changes caused by other factors: up to now this has not been proven.

In many tests, truth-tellers fail and liars pass. Some people may show symptoms – such as fear, for example – during the test, and so the device indicates that they are telling the truth [sic] even though they are honest. And many liars pass the test. Aldrich Ames1 passed the lie detector tests administered by the Central Intelligence Agency numerous times when he was working as an agent for Russian intelligence.

Manufacturers of the instrument admit this truth. As Dr. Bob Lee, former executive director of operations at Axciton Systems, a manufacturer of [polygraph] instruments says, “Polygraph instruments are designed to record involuntary reactions in the body when a person is subjected to stress, such as the stress that accompanies attempting to deceive, and the tests cannot determine whether a person is lying.” He also says, “What has happened over the years is that the media has dubbed this instrument the 'lie detector,' and so the name stuck, but from a scientific perspective, it's absolutely not.” And he adds, “There is nothing that detects lies. I couldn't tell you what a lie looks like.”

But many opponents of the use of this instrument go further than that. They see the chance of distinguishing between truth and deception using it as no better than the chance of tossing a coin and guessing on which side it falls. Some have described it as “voodoo.”

Former CIA director John M. Deutch says, “The CIA's reliance on polygraphs is stupid.”

John Sullivan, who will be mentioned below, says, “Polygraph is more art than science, and unless an admission is obtained, the final determination is frequently a guess.”

Professor John J. Furedy says, “The so-called 'control questions' are a flight of fancy. It is often used as a psychological tool for extracting confessions. The device is fundamentally based on a lie.”

Mark Mallah, a former American intelligence agent, says, “The lie detector is a failure. I think that its days are near an end.”

And the former American president Richard Nixon says, “I don't know how accurate it is, but I know it will make people very afraid.”

Nonetheless, we say that it is incumbent upon the mujahid that he strive to pass this test successfully without giving the enemies of God the information they want. The result they obtain, whether negative or positive, has credibility with them and will be an indicator that will help or hurt the mujahid.

In America, for example, after the blessed strikes of 11 September, the Federal Bureau of Investigation's polygraph failure rate for applicants reached about 50%, and the consequences of failure were severe for those who failed to pass the test:

So look at how important the result of this test is to them – despite their knowledge that the results are unreliable – and look at how they treat their own countrymen if they fail the test, and you can imagine their attitude regarding a mujahid who doesn't pass it.

And Now...How Do I Pass This Test?

There are many tricks for fooling the device. We must realize that the idea of the device is based on measuring the body's physiological changes. Thus, if the mujahid is able to control these changes, it will enable him to fool the device.

The important principle for passing the test is for physiological reactions while answering “control questions” to be stronger than reactions while answering the real questions, so that the interrogator cannot distinguish between true and false answers.

“Control questions,” as we mentioned earlier, are questions with known answers that establish the body's natural physiological level, and that is for comparison with the result obtained by the interrogator when answering the real question.

For example, the interrogator takes some pictures, then asks the person to choose one, then the interrogator shows the pictures one after the other asking, “Is this the one you chose?” and to convince the mujahid of the device's effectiveness, he asks him, if he sees the picture he chose, to deny it! He records this result for comparison with the other results.

If the device is able to identify his lie as a result of physiological changes during his answers because of the mujahid's inability to control them, the interrogator will inform the mujahid of the result, and what appeared to him as an indication of his deceptive answer, in order to convince him of the device's effectiveness at detecting lies and as a means of applying psychological pressure on the mujahid to confess everything he knows in detail, fearing that the device will detect it! And this is what is of primary importance to the interrogator: the information divulged during the test and not the result. Let this be noted well.

Control questions may be presented differently from the foregoing, wherein the interrogator asks extremely broad questions such as, “Have you ever gotten out of trouble in your life? Have you ever stolen anything in your life? Have you ever lied in your life?” And so forth.

The mujahid may partially control his involuntary physiological changes by many methods, among them: doing mental arithmetic, thinking about moving things, contracting the muscle of the posterior,2 or biting the side of the tongue. Despite repeated claims by examiners that they can detect these countermeasures, none of them have proven it. On the contrary, the undetectability of these countermeasures was established in research conducted by some experts.

It may sometimes be useful to take sedatives and sleep-inducing drugs, to rub antiperspirant on the fingertips, and to cough, but these aforementioned things are not the ideal way to pass the test.

Let us now consider these countermeasures in some detail:

Controlling Breathing Rate:

The mujahid must train to control his breathing rate in various situations during the test and strive to take from fifteen to thirty breaths – inhalation and exhalation – per minute, or one breath every two to four seconds. And he should strive to avoid taking deep breaths during the interrogation. Instead, all breaths should be the same length, and he should be careful not to return to his normal breathing pattern until all the wires are disconnected from him, because often, the interrogator will leave them on for a time after the questioning is over to verify that the mujahid is not using a countermeasure.

Controlling Blood Pressure:

The countermeasure that concerns us here is that the mujahid is able to increase his blood pressure rate above the usual rate, and to do that, the mujahid must do one of the following while answering the “control questions”: conduct complex mental arithmetic as fast as possible, such as taking an arbitrary number, for example 768, and counting backwards, repeatedly subtracting 9, as fast as possible, or thinking about exciting things, such as imagining oneself upon a precipice or drowning in water, and so forth. The goal, as we mentioned, is to raise the blood pressure when answering the “control question.”

It is incumbent upon the mujahid to do such things as soon as he decides whether the question is one of the “control questions.” He should begin doing so right away and continue until before the asking of the next question.

The Tongue:

One effective way to fool the lie detector is to bite the side of the tongue until the mujahid feels moderate pain, but without injuring himself, and being careful that the interrogator doesn't notice it. This requires that the mujahid practice in front of a mirror until he perfects it.

Here, my mujahid brother, are a number of pointers to keep in mind during interrogation:

In closing, my brother mujahid, you must be completely aware, should you be destined to undergo this lie detector test, that the lie detector is a misnomer, and that the enemies of God fully understand this, but they use it for its psychological effects on those who don't know the truth about it to obtain as much information as possible.

1He was discovered in 1994 and is considered the agent who caused the greatest damage to the United States, as he disclosed all the names of its spies on Russian territory.

2Some new instruments are equipped with a device that detects movement of the muscles of the posterior.

Translation, transcription, and HTML by Home Page > Reading Room