Lie Detection

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. 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.