History of Polygraph

The need to detect deception is not a new phenomenon. Humankind has been dealing with deception since the dawn of civilization. Earlier techniques for detecting deception had their basis in superstitions and religious beliefs. As the advancements in technology and knowledge of the human body grew, the basis for deception detection leaned towards the physiology and anatomy of the human body. The earliest use of this knowledge for detecting deception is credited to Erasistratus, a Greek physician who served as a royal physician under Seleucus I Nicator of Syria. He used the pulse to detect deception. Later, in 1581, Galileo Galilei invented “Pulsilogium”, which made counting pulse rate possible. This device was also known as the “Pulse watch”. This discovery paved the way for a deeper understanding of blood pressure volume and its measurement. Blood pressure was discovered by Stepehn Hales, an English physiologist and chemist, in the year 1773. Following this, Andre Ampere, in the year 1820, constructed a device to measure electrical currents in the human body, which he named ‘Galvanometer’ in honour of Luigi Galvani, an Italian Physicist credited for the concept of ‘Animal electricity’. The year 1856 saw the making of the first direct blood pressure measurement in humans by Auguste Faivre, a surgeon, which paved the way for one of the sensors used in the deception detection technique. Another ground-breaking research study was done by Angelo Mosso, an Italian physiologist, in the 1890s, where he studied the effect of fear on the cardiovascular and respiratory systems. He proposed that during times of emotional stress, such as fear of getting caught in a lie, blood rushed to the head of the individual. This would explain the flushing of the face during an emotionally charged situation. He also theorized that the person’s body weight would shift slightly during this time. This change in the volumetric displacement to measure the emotional response during deception was made possible by Mosso’s mentor, Cesare Lombroso, in 1895. Lombroso successfully used the plethysmograph to detect deception and became the first person to use scientific instrumentation to detect deception. He is also named the ‘Father of Modern Criminology’.

Another important discovery was the application of a galvanometer for the detection of deception. The credit for this goes to Harold Sticker, who became the first person to apply the principles of Ampere to measure physiological change. He theorized that the activity of sweat glands increases during stress. He believed the skin conductivity could be measured using a galvanometer attached to a person that would allow the observation of Galvanic Skin Response (GSR). This response was believed to be the result of mental excitation. The use of GSR gained popularity, and by the 1950s, GSR instruments were made available to detect deception.

In the early 1900s, Hugo Mustenberg, in his book, ‘On the witness stand’, mentions the importance of emotions and their role in detecting deception. He emphasizes measuring various physiological parameters such as eye movement, blood pressure, muscle contractions, breathing, and changes in electrodermal activity to detect deception. This publication led to several research studies in the area. One noteworthy research was by Vittorio Benussi in 1914. He measured the inhalation exhalation ratio and found that this ratio was different for conscious deception than normal. During conscious deception, the inhalation became quick, and the exhalation became longer. In 1917, Willian Marston* researched the differences in systolic blood pressure to detect deception. He also started to conduct research on the use of a galvanometer (GSR) to detect deception and compared it with the results from systolic blood pressure research. He concluded that systolic blood pressure was better at detecting deception. The work done by Marston and Benussi is noteworthy in the history of polygraphs. When Sir James Mackenzie, a Scottish physician, developed an ink polygraph instrument to record the physiological changes during the interview process, John A. Larson combined this breakthrough technique with the research done by Marston and Benussi to measure and record these changes. Later Larson developed a “two-pen Lie detector”. He used to measure more than one physiological change simultaneously through this lie detector. He named this instrument the “cardio-pneumo-psychogram”. He would use a revolving drum of smoked paper to document these physiological changes. Larson also became the first person to administer polygraph tests on the prisoners to assess their truthfulness. Larson’s student Leonard Keeler 1925 improved the polygraph technique developed by Larson by adding inked pens to document the changes and eliminating the use of smoked paper. He then became the first person to manufacture this improved polygraph and brought it to the commercial market in 1926. He later added a third physiological sensor to the polygraph, the psychogalvanometer. He added this to measure the person’s galvanic skin resistance, respiration, and blood pressure. Thus, he gave birth to the modern polygraph that we see today and is known as the “Father of Modern Polygraph”. He also founded the first polygraph school in the world- the Keeler Polygraph Institute.

Narco-Analysis Test & It’s Uses in Forensic Science

The Polygraph stands on the works of many notable people who contributed to the scientific community to understand the human body’s physiology, psychology, and anatomy. Their contributions paved the way for forensic psychology to become a discipline that detects deception.

The famous case of Frye vs the United States

A prominent physician in the United States was murdered. The police offered reward money to anyone who provided substantial information. An informant gave the name of Alphonzo Frye as the perpetrator. The police made an arrest, and the case went to trial. Frye had earlier confessed to the crime but later retracted the confession. The defence hired Marston to conduct a polygraph test on Frye. Marston conducted the polygraph test and concluded that Frye was innocent. Using the technique developed by Larson, the prosecutors argued that Marston only used one physiological measure, and thus the results could not be trusted. Frye was charged guilty for the murder he did not commit. This case was remarkable because the Frye standard was developed. In this case, the jury did not let Frye present the findings of the polygraph done by Marston. They also did not call Marston for the expert testimony. They later made a rule on the admissibility of the evidence presented in the court which is still the basis today. The rule mentioned that the expert testimony presented in the court deduced from a scientific discovery or principle must be well established, recognized, and accepted in the scientific community and the particular field to which it belongs. Since the principle of systolic blood pressure was not established and did not have sufficient scientific recognition among physiological and psychological communities, it was rejected as evidence in the Frye case.

*Fun Fact: William Marston is the creator of the now very famous DC character Wonder Woman, who uses her special lasso to make her enemies tell the truth.

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