History of Polygraph essay


The focus of this paper is on the exploration of the historical perspective of polygraph, the current use of the device in various fields, its advantages and drawbacks and other methods of deception detection. The issue of lie revealing has gained a great importance over the past decades. The primary reason for this is that law advocates, employers and representatives of other fields resort to the help of polygraph results. This paper explores the advent of the polygraph prototypes, their evolution and updating. Names of scientists and psychologists who have made a great contribution to the enhancement process and the invention of the deception detection device are mentioned in this paper. In addition, pros and cons of polygraph usage are discussed, as well as modern techniques of lie revealing in order to cover the whole ground.

History of Polygraph

Historical Perspective

Polygraph has a long history as the problem of lie detection bothered mankind since time immemorial. People had been using a variety of ways in order to expose a liar during the ancient times. Historical and literary sources indicate that complex rituals were developed for this purpose. A desperate attempt of humanity to invent a lie detector starts from various techniques and methods. However, the invention of a lie detector machine dates back to the 19th century.

Famous search for truth was mentioned in the Bible. Two women resorted to the King Solomon and asked him to define who was a true mother of an infant. His decision was based on the observation of women's emotions and demeanor. Solomon ordered to cut the infant in half in order to solve the problem. One woman looked terribly upset and abandoned the claim while the other calmly agreed with the idea of division. Solomon decided in favor of the woman who was scared to death of his advice. Only the true mother can not allow killing her baby.

In the early 19th century professor H. R. Crosland has developed a word association test that helped to detect a strong feeling of guilt instead of revealing a lie. 2.5 seconds were considered to be the normal reaction time. The longer reaction signaled about emotional disturbance or word selection. This meant that people did not say the first thing they thought about. Word association test was not being viewed as a reliable method of lie detection by law court (Servage, 2004).

A. Mosso is a famous physiologist in the field of emotions. He had been studding the feeling of fear and its influence on respiration and heart for continues period. Physiologist noticed that fear is an inherent evidence of deception. Lombroso is considered to be the tutor of A. Mosso and the person who firstly used a scientific instrument for the purpose of lie detection. He took suspects' blood pressure during the course of trial examination. Lombroso assisted the police in identifying the criminals by means of blood pressure monitoring. He used sphygmograph is a device that records the strength, rapidity and uniformity of the arterial pulse. B. Sticker also suggested the application of psycho-galvanic reaction to judicial problems. Psychiatrist Munsterberg and C.G. Jung claimed that attempts at lying or evasion could be easily revealed by means of the blood pressure test and association tests.

Galvanometer belongs to the deception detecting devices. It was named in honor of Italian psychologist Galvani. The device measured changes in the electrical conductivity of the person's skin. B. Sticker noticed that the emotionally aroused people would have a significant skin excitation in comparison with those who was emotionally unmoved.

James Machkenzie is a famous heart specialist who invented the first so-called 'polygraph'. At the very beginning this instrument was developed for the medical purposes and had nothing to do with the lie detection. The device was first presented at a meeting of the British Medical Association in 1906. Over a number of years, the instrument became more advanced. Polygraph has contained 16 channels by the early 1970's. The general media preferred a term 'lie detector' to the term 'polygraph'. Representatives of the deception detection industry persuaded the general public to not use the misnomer. They explained that an operator determines if the deception was implicated while the instrument only records changes in psychological processes. However, the explanations did not make an impact on the public as the majority continued to use an incorrect term (Bunn, 2012).

Scientific studies that directly led to the invention of the modern polygraph began in 1914. Physiologist Vittorio Benussi suggested the use of the respiration measuring as an index of deception. In other words, he presented Inspiration/Expiration ratio or 'Benussi ratio'. The device that recorded respiration was called pneumograph. Benussi noticed that the inspiration to expiration ratio was usually greater before telling truth than that before deceiving. The duration of inspiration and expiration was measured immediately. Moreover, delivering of a true statement diminished while delivering of a false statement increased. People who resorted to irregularly breathing in order to avoid detection could not manage as voluntary changes in respiration did not affect the result. Harold Burtt continued to develop Benussi's method. However, he has discovered that blood pressure showed a greater diagnostic value than breathing.

William Moulton Marston is known as a prominent figure in the process of lie detector updating. He began scientific work in 1913 in Harvard. Marston noticed that normal person can not lie without effort. He suggested using the sphygmomanometer - is the apparatus that measures changes in systolic blood pressure. The device was accurate in 103 out of 107 cases (Servage, 2004).

A modern version of lie detector was developed by a Canadian psychologist John A. Larson in 1921. He combined both respiration and blood pressure measuring units in one device that was called polygraph. It could read and document several psychological responses at the same. Larson was able to simultaneously measure changes in blood pressure, respiratory and pulse rates during his investigations. His polygraph was frequently used in forensic interrogations.

Leonarde Keeler had worked with Larson at the Berkeley Police Department. He had amassed a wealth of experience while collaborating with Larson. As a result, Keeler also had made his contribution to the improvement of polygraph. He devised it with inked pens, thus eradication the need for smoking and preserving the paper with shellac. In 1926 the enhanced version of polygraph came on the market.

In 1938, Leonarde Killer equipped it with psycho-galvanometer is a unit that measured changes in the galvanic skin resistance. He patented his invention in 1939. Nowadays Leonarde Killer is considered to be the father of polygraph. However, he refused to call his invention a lie detector and described it as an 'instrument' of an operator. Killer explained that the most significant part of the lie detection process was the decoding of the polygraph records. In other words, the effective use of the device depends on the skill of the operator.

Nowadays polygraph examination is closely related to psychological testing that is presented as a serious of tests. These tests can help to define the truth or deception in situations that range from job applicants selection to criminal investigation. Modern polygraph is a three or four channel machine that records three physiological responses on a moving chart. An average polygraph examination lasts from 1 up to 3 hours. It length depends on a number of factors. Examinations may be longer than 3 hours if an examiner tries to resolve an incoherent pattern of responses (Abelson, Frey, Gregg, 2004).

Cons and Pros of Polygraph

Scientists have been exploring the benefits and drawbacks of polygraph since its appearance. Polygraph test is an important method of proving the evidence of guilt or innocence of the subject. This device allows detecting a lie at a quick pace. Moreover, polygraph is a means of identifying persons involved in crimes, as well as the prerequisites for the illegal actions (criminal history, drug or gambling addiction, psychological disorders). In addition, polygraph examination is the best way to minimize mistakes while employing people. Besides, polygraph testing is an independent investigation which can strengthen or weaken the results of the official investigation.

However, comparably low validity (maximum - 70%) of the polygraph test was mentioned among the cons of the device. High probability of confusing and deceiving the lie detector by means of different methods (drugs, alcohol, tongue biting, pressing the tips of toes, switching thoughts on abstract themes) belongs to its drawbacks. Furthermore, unqualified polygraph examiners can incorrectly interpret polygraph records. On the top of everything else, testing result is often considered as circumstantial due to a lack of rules regulating the use of the polygraph. In other words, polygraph examination is regarded as an invasion of privacy life in some cases (Dempsey, 2008).

Deception detection techniques

At present, a great variety of deception detection tools, methods, techniques are available to the contemporary psychologists. Advanced technologies range from instruments for detecting lie through emotions expressed by face muscles and body gestures to equipment for voice analysis. State of anxiety that occurs when a person lie is reflected in minor voices fluctuations that can be easily registered. A variety of devices for the detection of stress in the voice come on the market. Psychological Stress Evaluator (PSE), the Mark II Voice Stress Analyzer (CVSA) and Computerized Voice Stress Analyzer (CVSA) are the latest devices that are usually presented as a new era in the lie detection field.

Thermography is used to assess changes in the blood supply to the selected parts of a face. Sometimes changes in the blood supply are evident, for example, when a person blushes. However, the main aim of the thermography is to detect transient blood flow changes caused by the activity of the sympathetic nervous system. The obvious advantage of this instrument is the possibility of using it secretly as the device is designed for remote registration of the thermal changes.

Assessment of pupil size and its reaction is used in a number of applied areas. The first attempt to use this method for lie detection purpose was made in the early 40th of the last century. Studies have shown that changes in pupil size were observed during the process of lying (Kaizen, 2010). Although there are many methods of lie revealing, polygraph remains the best means of deception detection.

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