In a typical examination, says Wasser, the subject will be wired on his upper chest, his abdomen and his fingers, as well as with the cuff. The subject will even help me draw up the questions. There are no surprises, no dirty tricks on these tests. And afterwards we go over the results in detail. If a subject is lying, he usually tells me so before we ever get to that point.
Some people believe they can beat it by taking drugs.
But I want them to come in here in their normal physical condition. If the guy I'm talking to is a heroin addict, I don't want him going through withdrawal. Polygraph measures the body's normal responses. His body still responds to threats the way our most remote ancestors did, and one is generally unable to control autonomic responses such as blood pressure and palm sweating. Four groups of 20 people were told to drop off or pick up packages from two doormen at a building.