The Invention and Evolution of the Lie Detector
Throughout history, people have been fascinated by the problem of truth and lies. They have long wondered how to distinguish between the two and how to deceive without being caught. Scientists eventually stepped in and developed a device for detecting lies—the polygraph. This method of investigation gained widespread popularity, especially in law enforcement. The more familiar term “lie detector” was later coined by journalists.
Ancient “Lie Detectors”
Is a person telling the truth? Judges have asked this question throughout the ages. To determine guilt, they used the most elaborate methods, such as ordeals, commonly known as “God’s judgment.”
In Ancient Rus’ during the reign of Yaroslav the Wise, a kind of civil code was created that clearly defined which ordeal an accused person should undergo, depending on the size of the “claim.” Usually, the test involved fire or water. The defendant had to hold a piece of red-hot metal or retrieve an object from a cauldron of boiling water. The latter method was used if the value of the disputed item was small. Afterward, the judges would tie the person’s hands and leave them for three days. The absence of wounds, scratches, or burns was considered proof of innocence. Naive people believed that God would surely help the wrongly accused. Of course, this faith was sometimes exploited for personal gain. The famous historian N. Karamzin noted that this was a dark and extremely cruel time.
Similar “God’s judgment” ordeals are found in the history of other peoples, such as the ancient Germans. Even today, some places in Africa still use similar methods to resolve disputes. However, not all cultures were so harsh in their search for the truth.
For example, it was observed that hiding the truth affects many physiological functions. In ancient China, judges tested the accused with rice. The defendant had to put a handful of dry rice in their mouth while the judge stated the accusations. It was believed that fear of being exposed would stop saliva production. If, after the accusation, the rice taken from the suspect’s mouth was still dry, the person was automatically considered guilty.
The ancient Indian method of detecting truth was also interesting. The accused was given words related to the crime and had to respond with the first thing that came to mind while lightly striking a gong. When a more “critical” word was mentioned, the person would hesitate and strike the gong harder. Of course, these methods were highly subjective and did not account for individual differences.
The Emergence and Use of the Polygraph
Cesare Lombroso was the first to introduce a device-based method for detecting lies, which attracted attention but did not gain widespread acceptance. Only in 1913 did William Marston, a well-known American lawyer and psychologist, begin to study the topic in depth. World War I created a need to identify spies and combat enemies. To achieve this, a U.S. research laboratory assembled prominent psychologists, including Marston, to explore the possibility of detecting lies using devices. The experts concluded that the most effective method was to detect lies by monitoring changes in blood pressure. Marston developed this method in a psychological laboratory, achieving nearly 100% accuracy.
The psychophysiological method of lie detection found followers: in 1921, police officer John Larson implemented it in his police department after confirming its effectiveness. Later, in 1923, Marston was the first to use polygraph data as evidence in court. Soon after, Larson developed a portable lie detector that accurately recorded physiological indicators such as breathing and pulse.
In 1933, Larson’s student Leonarde Keeler created a polygraph model that was used until recently. Two years later, he developed a detailed testing methodology, and it was Larson who first opened a school for polygraph examiners and launched the industrial production of lie detectors. He later proved the indispensability of such devices for police and security agencies.
The Spread of Polygraphs
By the 1940s, the vast majority of police departments were equipped with lie detectors, which greatly aided in solving various crimes and significantly increased law enforcement productivity. In addition, large companies and banks began using polygraphs to screen their employees.
With the onset of World War II, the question arose of using polygraphs for national security. Tests showed that the technical capabilities and condition of the devices were well-suited for this purpose, provided there were qualified specialists, as the accuracy of results depended directly on them. Thus, the polygraph began to be used to protect state secrets, such as during the construction of the atomic bomb.
The Polygraph in Soviet History
Interest in this method of investigation arose not only in the United States but also in other countries, including the Soviet Union. In the 1920s, Soviet scientist and psychologist Alexander Luria developed an associative method successfully used in solving serious crimes. The method was based on reflecting the suspect’s psycho-emotional state in their speech, somewhat similar to the ancient Indian gong test.
The accused was given words to which they had to respond without thinking, while squeezing a rubber bulb in their hand. When a more “critical” word was mentioned, both verbal and motor responses were delayed. Unfortunately, after a few years, all research and practical use of the polygraph in the Soviet Union was halted, as it was deemed unscientific. The polygraph was forgotten for 30 years. In the 1960s, work resumed, but after 10 years, research was again discontinued.
However, Soviet security services continued to work with the polygraph and, by the 1980s, had created a prototype of the modern computerized device. Today, polygraph data is not used as evidence in court, but police widely use them for examinations and to determine a person’s involvement in crimes.
The Polygraph Today
Today, the polygraph is a portable computer equipped with sensors to read and record physiological parameters and changes in the autonomic nervous system of the subject.
The “accuracy” of the results depends directly on how many parameters are measured. In addition to the test results, a person’s general physiological characteristics are also considered. The polygraph does not reveal the whole truth; it simply shows how anxious the subject is during the test. The reasons for such emotional states can vary. The interpretation of lie detector results depends solely on the polygraph examiner and their level of expertise.