Homework Help: Social Studies: Psychology: The Lie Detector – Does It Really Work?
by David A. Gershaw, Ph.D. Most of us have seen movies in which a suspect has been given a lie detector test. More recently, lie detectors are being used by some large companies or governmental agencies, when they interview prospective employees. How does a lie detector work? Are lie detectors efficient in detecting lies? The concept of a lie detector is centuries old. The ancient Chinese had a suspect chew dry rice while he was being questioned. After questioning, the rice was examined. If it was dry, the suspect was assumed to be guilty. As was assumed then – and is currently supported by more recent evidence – the nervous tension created by lying slowed or blocked the flow of saliva. Thus, the dry mouth lead to dry rice and a guilty verdict. The modern lie detector – the polygraph – does not use dry rice. (“Poly-” means “many,” and “graph” refers to “something that writes or records.”) The polygraph records several different activities at the same time. Typically it involves a pneum
