LIE DETECTORS

Polygraph: The Truth about Lie Detectors

Polygraph: The Truth about Lie Detectors

Introduction

Up until the 1900s, unscientific methods dominated the search for detecting liars from truth-tellers. Many methods relied on divine intervention, expressed through ordeals or torture that was rooted primarily in superstition and religious faith. In Europe and colonial America, water ordeals flourished during the witch hunts of the 1600s, when suspects were tied up and thrown into water. If the suspects sank, this meant the water had accepted the purity of truth-tellers; if they floated, it meant the water had rejected the impure liars, who were then executed. Another testing method, the boiling water ordeal, in which the right hand of the accused was plunged into a kettle of boiling water, was used worldwide, whereas fire and hot iron ordeals were commonplace in India and Egypt. Food ordeals involving the chewing and spitting out of dry rice were practiced in ancient China, and during the Spanish Inquisition, a “trial slice” of bread and cheese was used to test the veracity of suspects. (Manatu, 2004) The belief underpinning food ordeals was that lying produced reactions of fear and guilt, which caused a decrease in saliva production. If dry-mouth made spitting and swallowing difficult, suspects were declared deceptive. Although ancient techniques for detecting lies were torturous, they had in common with their modern counterparts reliance on the psychophysiological overreactions of suspects. Not until the early 1900s did science intervene with the hope that truth could be uncovered painlessly (Manatu, 2004).

Discussion and Analysis

The ability to regularly, even easily, purposely deceive others is a characteristic that humans believe sets them apart from other species. Since human life began, humans have tried to develop methods to determine if others are lying to them. Are any of these methods effective? People have used various methods in this endeavor, including looking at how people behave, listening to how they speak, analyzing what they say, and examining their internal bodily or brain activity. Research, however, suggests that there is no uniformity in human behavior that demonstrates the same kind of differences between lying and truth telling (Bull, 2007).

Many people feel aroused when telling big lies and expect others to feel the same way. Therefore, they expect that liars' visible behavior will be such that liars will find it difficult to look another person straight in the eye. Numerous research studies have shown that not only lay people but also professionals such as police officers share consistent beliefs about the existence of behavioral cues to lying. Studies have also shown that most people who lie do not behave in line with these beliefs. Most liars are aware of these beliefs and so, when they lie, they try to behave in ways other than the expected ones (for example, they look another person in the eye and mute other obvious behaviors). This helps to explain unsuccessful attempts to detect lying by observing behavior. Recent research studies have found that police officers who believe that a variety of behaviors can ...