A polygraph is a relatively simple instrument that monitors and records physiological activity in someone’s body. A standard polygraph monitors changes in blood pressure and heart rate, breathing patterns, and perspiration on the fingers or palms. If the polygraph is operating properly, it does an excellent job of recording those activities. However, it doesn’t do much more than that.
The polygraph is part of a technique that determines whether a person is being truthful or deceptive when answering certain questions. The polygraph test, if done properly, can accurately make that determination almost all of the time. But the polygraph itself does not tell us if someone is lying or telling the truth. It is not a lie detector or a truth detector. It merely records physiological activity. Truth or deception is determined by the polygraph examiner. The examiner is trained in many things, one of which is to analyze and evaluate the physiological activity he sees on the polygraph charts. A skilled and experienced polygraph examiner, like any other serious professional, will make the right calls the vast majority of the time.
Tags: polygraph, polygraph examiner
