The development of human relationships was never simple, and as soon as one problem was solved, another concern occurred. In the majority of cases, challenges in communication were provoked by the desire or necessity to lie. The intention to detect deception and find out the truth motivated people to think about new methods of cooperation and research. With time, effective legal systems, social norms, law enforcement, and courts were introduced, and society was in need of technologies to detect lies and verify evidence. As a result, the first polygraph tests were created at the beginning of the 20th century and improved within the next several decades. Today, the purposes of using a polygraph vary, but the main idea remains the same – to hear the truth. People enjoy TV shows where Wonder Woman compels people with her Lasso of Truth, or Dr. Cal Lightman (Lie to Me) uses his applied psychology knowledge to analyze human expressions and body language. Truth becomes a kind of critical trend for people of all ages. The benefits and shortages of polygraphs will be discussed in this report, along with its history, technological aspects and methods.
In today’s society, people know a polygraph as a lie detector test. Some couples find it funny to use this technique and check their feelings. However, in the majority of cases, polygraphs are necessary to detect crimes, investigate cases, and improve the quality of work in various organizations. At the same time, despite the purpose of detecting lies, polygraphs could be defeated. After the example of Aldrich Ames, who was arrested because of international espionage in 1994, the quality of lie detectors was questioned (Hart, 2020). This man was tested several times and passed everything successfully, so that no one could guess his deception as a Russian spy (Hart, 2020). To understand how polygraphs work and what their true purposes are, the history of this technology development has to be thoroughly studied.
History of a Polygraph
The history of a polygraph is characterized by a number of events and people who made certain contributions to the development of this technology. For example, according to the official sources, the name of John Larson was closely related to the invention of the first polygraph in 1921 (Synnott et al., 2015). His idea was to create an instrument with the help of which such vital signs as blood pressure, heart rate, and respiration rate were measured, and their changes signalized about deception (Synnott et al., 2015). Respiration and pulse waves were recorded on a smoked drum chart. The apparatus consisted of three main components, including a pneumograph (respiratory rate recorder), a galvanograph (perspiration production), and a cardio-sphygmograph (blood pressure and heart rate recorder) (Krapohl & Shaw, 2015). However, it is wrong to consider Larson as the only developer and a true inventor of the polygraph.
The first attempts to identify deception were made a century before Larson offered his invention. In 1878, a student Angelo Mosso, in cooperation with his mentors, researched fear and respiratory and cardiovascular responses with the help of the scientific cradle on the basis of a plethysmograph (Krapohl & Shaw, 2015). However, he was not able to put his theoretical ideas into practice and introduce enough evidence. In 1895, Cesare Lombroso, who was one of Mosso’s instructors, focused on the problem of sensitivity and used scientific instrumentation to show how to detect deception (Gordon, 2016). Today, this person is called the “father of modern criminology” (Gordon, 2016). During the next years, scientists, including Sticker, Veraguth, and Munsterberg, improved the idea of lie detection by applying new instruments. In 1915, William Marston introduced a discontinuous systolic blood pressure test. Its results were applied as evidence in the court during the United States v. Frye case in 1923 (Gordon, 2016). Although the jury found the man guilty as the blood pressure could not justify a murderer, a scientific recognition of the invention was approved, and many people became involved in similar research.
All these scientists and their contributions created a solid background for the work of Larson. Along with his protégée, Keeler, who became the “father of modern polygraph”, he continued improving the instrument (Gordon, 2016). Keeler was the inventor who offered the polygraph for commercial purposes and put financial needs in the first place. He made the polygraph portable and added a sensor to measure galvanic skin response (GSR). John Reid continued the study in the middle of the 1900s, introducing the Reid Technique (to interview and interrogate) and a Comparative Question Test (CQT) (Synnott et al., 2015). With time, polygraph standards have been considerably changed and improved, but the above-mentioned names and achievements served as the crucial historical elements of the history of the device.
Polygraph Technology Development
Compared to a number of devices that created a full polygraph during the 1900s, modern polygraphs introduce a small digitalized instrument with a laptop to record signals. Three activities are usually measured and analyzed by users, including cardiovascular activities, respiratory activities, and electro-dermal activities (Synnott et al., 2015). To measure cardiovascular changes, a sphygmomanometer (or a blood pressure cuff) is placed around the arm where a brachial artery is located (Krapohl & Shaw, 2015). This activity resembles a well-known medical practice to check the patient’s blood pressure. If the cuff cannot be put on the arm because of some reasons, photoelectric plethysmographs are offered to be placed on the client’s finger or ear (Synnott et al., 2015). Photosensors are used to measure the light in the tissue segments and check the condition of blood during an investigation.
Electro-dermal activities are studied by means of the sweat on fingertips, and galvanometers help to detect if there is any galvanic skin resistance. Skin conductance is defined as one of the most reliable means to measure changes in the body (Synnott et al., 2015). It is necessary to place two electrodes to fingers and follow if the hydration of the skin happens during an interview. In the majority of cases, stress related to deception or the inability to reveal the truth results in perspiration, and people cannot control this process. When such electro-dermal activities are observed, polygraphers report for a further analysis to be developed.
During a long period, respiratory activities were measured by rubber bellows that were the part of pneumographs to place around the chest and abdomen. As soon as abdominal muscles expanded, the air in the tube changed, and the pen detected the reaction. However, according to the observations of Synnott et al. (2015), this method was characterized by low-frequency response. Therefore, today, pneumographs are no longer in use and have been replaced by transducers that convert the energy into electronic signals. However, in general, these three techniques explain how any polygraph works and what systems are checked.
Modern Polygraph Methods
One should admit that polygraphs alone cannot be used as a single technique to reveal the truth. Polygraph examinations have to be conducted in regard to the standards developed by the National Center for Credibility Assessment, which includes the implementation of two tests, a Concealed Information Test (CIT) and a Comparative (or Control) Question Test (CQT) (Synnott et al., 2015). CIT is also known as the Guilty Knowledge Test (GKT) and defined as one of the most scientific techniques in lie detection (Krapohl & Shaw, 2015). However, both tests have its supporters and opponents due to the offered approaches and expected results.
The CQT format aims at comparing the responses to different questions (either relevant or control). It was revealed that people who tell the truth (innocent people) have specific reactions to control questions, while deceivers (the guilty ones) are caught at control questions. Using the relevant/irrelevant paradigm, the authors of the question are able to identify guilty and innocent suspects by analyzing their physiological responses and the level of stress (Yu et al., 2019). At the same time, the CQT approach causes a number of critiques because of the impossibility to differentiate between the concerns of innocent people (because some people always have some past events to be hidden). As a result, innocent people may be worried about relevant questions due to their inner logic, and examiners have to develop additional strategies to reach the required emotional state (Synnott et al., 2015). Judgments about deception and non-deception may be inconclusive, which requires the implementation of additional techniques.
CIT or GKT procedures were promoted in contrast to CQT techniques because it was necessary to remove human emotions from answers but focus on the physiological signs. The CIT introduces a series of questions with one critical item only (Krapohl & Shaw, 2015). As the order of questions is always randomly selected, it is hard for an individual to predict the reaction and understand when a trick question occurs. For example, to investigate a crime, an examiner develops the questions, the correct answers to which could be familiar to a criminal only. To get prepared, an examiner should have access to crime-relevant information, and it is important to use the facts that have not been mentioned in the media or other publically available sources (Synnott et al., 2015). As well as CQT, CIT examination consists of three phases – a pre-test interview (to gather general information), a testing phase (to ask necessary questions), and a post-test phase (to evaluate data).
Pros and Cons of Polygraph Technology
Despite the method and technology chosen for a polygraph, the main purpose of this device is to detect lying. Polygraph examinations are frequently used in the United States, Canada, and Japan for legal and employment goals as well. At the same time, it is necessary to admit that polygraphs promote security at national and international levels because it is a good opportunity to identify threats and follow other dangerous sources. According to Yu et al. (2019), the technique of polygraph is necessary to differentiate the intentions of travelers – terrorists, regular visitors, or drug traffickers. The ability to study people as soon as they come to the country or when they apply for a job is characterized by a number of benefits. Employees understand what to expect from potential workers, and the security system prevents the growth of crimes or other frauds.
As well as any modern technology, polygraph examination may be criticized by its opponents. For example, many cases of examination are translated on TV or thoroughly discussed in books. Such sources provide criminals with a chance to understand what to expect from polygraphs and learn how to defeat them (Hart, 2020). Accuracy rates are never the same, and no examiner will give 100% guarantees that their results are true. Sometimes, the costs of the technology do not meet the expectations, and countries or companies experience losses without any gains being achieved. Finally, to become an examiner with a polygraph, a person should have a certification and be educated at a specific facility. However, even the most aware people and the best technologies may not predict serious threats because of the existing organizational, financial, and personal factors.
Conclusion
In general, the use of polygraphs during the past several decades has considerably improved the quality of international and national security. Its history of development and the types of examinations show that the system is not simple, and people should work hard to gain benefits. People cannot stop lying because this activity turns out to be an ordinary thing in human life. At the same time, millions of people spend much time and certain efforts to understand how to detect lies and reveal the truth. Polygraph technology, with its rich history and a number of contributors, has already shaped the way of how crimes could be investigated and threats are predicted.
References
Gordon, N. J. (2016). Essentials of polygraph and polygraph testing. CRC Press.
Hart, C. L. (2020). Do lie detector tests really work? Psychology Today.
Krapohl, D., & Shaw, P. (2015). Fundamentals of polygraph practice. Elsevier Science.
Synnott, J., Dietzel, D., & Ioannou, M. (2015). A review of the polygraph: History, methodology and current status. Crime Psychology Review, 1(1), 59-83.
Yu, R., Wu, S. J., Huang, A., Gold, N., Huang, H., Fu, G., & Lee, K. (2019). Using polygraph to detect passengers carrying illegal items. Frontiers in Psychology, 10.