William James once said, “The greatest enemy of any one of our truths may be the rest of our truths.” It is true, since the early civilizations, that man has struggled to find ways to learn more about the truth in and around himself. In the ancient Hindu and Chinese civilizations, physiological reactions have been used to detect lies. Chewing and spitting a grain of rice is their lie detection process, and for the Chinese, a dry grain is indicative of guilt as rice sticking in the mouth is for the Hindus. Since then, despite the technological advancements of the succeeding decades and the development in studies and researches, the main goal and the basis for truth detection has remained unchanged—to detect truth and distinguish it from the lies using physiological indicators. Up to this date, the sole invention to ever take these physiological reactions in consideration is the polygraph, which remains one of the most effective ways to distinguish the truths from the lies.
So what exactly is a polygraph? The polygraph is an instrument, more commonly referred to as the lie detector. It is used to measure, analyze, and record physiological reactions while the examinee is asked a series of Yes or No questions. Invented in 1921 by John Larson, a medical student and a police officer from Berkeley, California, this machine was originally developed in accordance to the mandate of the then-police chief of Berkeley, August Vollmer, for the police force to use science to be more law-abiding and avoid the third degree. It was first created to identify reactions based on the systolic blood pressure test pioneered by psychologist William Moulton Marston, who later on became more popularly known as the creator of the comic book superheroine Wonder Woman.
The polygraph is known to us as the lie detector, but technically, it may be more apt to call it the “truth verifier” as the process involved in its use revolves around identifying changes in physiological reactions during deception. In fact, the term polygraph is believed to have come from Greek words which mean “many writings” as an allusion to the need for many pens during the use of its analog ancestors. Present-day studies would say that the name polygraph comes from the fact that the machine records several body stimuli responses all at the same time while the individual is undergoing the test.
Despite its name, the polygraph and the painless components that come with it do not, in fact, detect lies. These contraptions are simply used to measure, record, and analyze body indices such as blood pressure, pulse, breathing patterns, and skin conductivity. These physiological indices are believed to reflect certain signs that identify a liar. To measure the following indices, several components are attached to the polygraph, namely, the pneumograph, the galvanometer, and the blood pressure cuff. Some polygraphs also use activity sensors to record arm and leg movements.
Technological breakthroughs in the past decades have improved the retrieval and analysis of the data gathered during the lie detection test. From the primitive and manual rice chewing and spitting of the Chinese, to the early version of the pioneer criminologist Cesare Lombroso modified hydrosphygmograph which associated heart rate and blood pressure to lying, and eventually to Larson’s modern-day polygraph, the retrieval and measuring techniques used as well as the indicators being measured have varied and improved. However, after Larson’s invention, not much has changed except for the recording, data gathering, and analyzing methods which evolved from manual to analog and subsequently, digital and computerized.
Critics, however, question the very basis of the theoretical foundation of polygraphic lie detection instead of its quantitative measurements. According to them, while it may be generally true that lying may cause an individual to exhibit certain physiological reactions, the inherent infallibility of the polygraph rests on its lack of unqualified extent, which raises the basis for challenging its validity and efficacy. Some critics remain skeptical up to this date and they maintain the idea that the polygraphic technology operates purely on assumptions and is prone to error and misconceptions. Senator Sam Ervin, in his lack of faith in the polygraph, even said, “Polygraph tests are 20th century witchcraft.”
Despite its subjectivity and the spurious beliefs toward the polygraph, the simplistic foundation of this lie detection instrument has survived almost a century. Since its introduction in the late 19th century, polygraph technology has barely been improved upon, but the very foundation of the criteria which it employs to accurately detect lies has survived countless centuries. The primitive and simplistic idea that it is stressful for a person to lie, thereby prompting the body to have physiological reactions, gave the polygraph its inherent subjectivity, which until now is still unacceptable to the scientific, legal, and political communities.
Indeed, man’s search for truth has gone on for so long. To this date, it has remained as primitive and as simple as in the early civilizations as manifested by our own lie detector equipment—the polygraph.