Devices Used in Interrogation
The most important of these are lie detectors, and there are several kinds:
1) The Chaldean device [jahaz kaldan], which is the size of an electric welding device, on which "lie detector" is sometimes written. This phrase is used psychologically against the prisoner to convince him that it is an effective device, and at the same time, this is testimony to the device's ineffectiveness. If it were effective, that would not be written on it, and it would be used secretly.
The device works on the principle of measuring the prisoner's pulse. The wires are placed around his neck to transmit his pulse and trace his tension in real time. When the accused is asked about a sensitive matter and attempts to deny or evade it, his pulse increases and there is a sudden rise in the tracing, and at this moment, the interrogator presses an electric button and delivers a shock to the accused to dupe him into believing that the device has detected his lie. Frequently, prisoners discover the lie behind this device and its ineffectiveness when the interrogator presses the electric button when the prisoner is telling the truth about a matter. When the prisoner is asked a sensitive question and his pulse rises, the interrogator repeats the question a second time, and frequently his reaction does not diminish the second time, and thus the device indicates no surprise, just as there are people who do not ever react however sensitive the question may be, just as they have the ability to lie and dissemble with all ease, calmness, and spontaneity. Indeed, if the device really worked, all nations of the world would be using it and relying on it exclusively, but it is only used for gathering information.
2) A device that works by passing an electric current through the skin. An electric current is passed through the skin, and when the accused is asked about a sensitive matter, he experiences stress and a psychological reaction, as a result of which the body's resistance to the current changes, owing to the perspiration that accompanies the reaction. The instrument registers a change in the strength of the current, indicating that the accused considers the question to be sensitive.
3) The voice stress analyzer. It measures stress frequency in the accused's voice. When this frequency changes at a certain point, it means that the person is sensitive to this question and may be lying.
Primitive Lie Detection Methods
The ancients used various means to detect lies. For example, the Chinese used powdered rice. They put a quantity of it in the mouth of the accused and ordered him to chew it and spit it out. If it was found to be dry, then he was guilty. As for the Arabs, they would place a piece of hot iron on the tongue of the accused. If the tongue of the accused was not burned by the effects of the fire, then the accused was innocent. Both of these techniques depend on fear and strong reactivity preventing the activity of the human body's salivary glands.
Pure psychological means were also used to detect lies, among them that which is recounted regarding our Master, Solomon, when two women came to him arguing over a child, each claiming it was her son. He suggested that the child be split in half. One of the two agreed to this and was exposed as the liar.
The Jews used a darkened chamber in which was placed a sacred ass. Its tail would be daubed in a black powder. The accused would be asked to pull it, and if it brayed, he was guilty.
Avicenna relied on the pulse to discover that which a man hides. Once, in one of his travels, Avicenna entered a city. A relative of the governor was stricken with an affliction that baffled the local doctors. Avicenna was consulted regarding the patient and carefully examined him. Avicenna asked someone to recite the names of places and cities as he felt the patient's pulse with his finger. If a certain city was named, his pulse increased. Then they brought someone who knew all the streets and quarters of the city and recited them. When he mentioned a certain street, the patient's pulse quickened, whereupon the names of the families resident on that street were recited, and when [p. 66] the name of a certain family was mentioned, the patient's pulse quickened. Then Avicenna stopped the procedure, announcing that he had diagnosed the ailment, which was that the patient was in love with a girl of such and such a family on such and such a street in such and such a city. He was married to her and completely cured.
This involuntary sentimental response (** illegible word **) to women, and desired that its possessor keep it to himself.
Modern lie detectors rely in part on measuring the pulse and recording changes in it with an instrument called the polygraph, which depends on the pulse changing due to reactions such as fear and anger. When the accused faces a question that condemns him and tries to deny it, fear of detection causes his pulse to quicken.
The examiner begins by taking seven playing cards (for example) and asking the examinee to choose a card, look at it, and put it back in the deck. Then he tells the examinee that he is going to show him the seven cards in the deck one at a time, and he wants him to answer "No" when the cards [sic] he chose are presented. The procedure is repeated several times, and then the person undergoing the procedure is told which card he chose and the changes registered by the polygraph when he answered falsely are pointed out to him in order to convince him of the device's effectiveness against lies.
During the actual interrogation, questions unrelated to the subject matter [of the interrogation] are asked, among which are suddenly introduced questions closely linked to the subject like the role of the playing cards, and sometimes the polygraph registers a change when the accused is guilty, and the questions are repeated several times to observe the changes each time and confirm it.
Among the weaknesses of the device is that extraneous factors such as a sneeze or a sudden loud noise can cause a reaction like the reactions that accompany lying. Likewise, there are innocent people who when interrogated display nervous reactions not related to any particular questions and which may be displayed during periods of relaxation when no questions are being asked. In such cases, it may be necessary to repeat the procedure as many as ten times in order to be certain. Likewise, there are professionals who don't react at all. The device is of no use with them.
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