To unmask falsehood and bring truth to light. -- SHAKESPEARE
No normal human being wants to hear the truth. -- H. L. MENCKEN
It seems natural to believe that a machine can detect lying, a machine not so simple as a smoke detector, perhaps, but more like the cardiac monitor connected to intensive care patients in hospitals that turns on an alarm when heart action strays beyond normal limits. The familiar term "lie detector" conjures such an image, a machine that rings a bell each time the subject tells a lie. A moment's reflection makes clear that such a device could exist only if everyone produced some distinctive physiological response when attempting to deceive, a response never produced, for example, when telling the truth but feeling frightened or afraid that he or she may not be believed. As Dr. Marston correctly pointed out, "It is necessary to test for some emotion which will not be present unless a person is lying . . . some one bit of behavior which would always mean a person was lying. Early in the twentieth century this long sought symptom of deception was discovered." 1 As we shall see, Marston's claims of discovery were premature. But if there were such a specific lie response, then modern psychophysiological techniques would probably allow us to detect it and the dream of a genuine "lie detector" would be a reality. It will be instructive
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Publication information: Book title: A Tremor in the Blood:Uses and Abuses of the Lie Detector. Contributors: David T. Lykken - Author. Publisher: Perseus Publishing. Place of publication: Reading, MA. Publication year: 1998. Page number: 53.