• The Polygraph – History and Evidence

    This post is part of a series of guest posts on GPS by the undergraduate and graduate students in my Science vs. Pseudoscience course. As part of their work for the course, each student had to demonstrate mastery of the skill of “Educating the Public about Pseudoscience.” To that end, each student has to prepare a 1,000ish word post on a particular pseudoscience topic, as well as run a booth on-campus to help reach people physically about the topic.


    The Polygraph – History and Evidence by Trey Ridlen


    People are poor at detecting if someone is lying. This is why human history is riddled with people coming up with various techniques and instruments to make up for the lack of accuracy in their judgements. One of these instruments developed in the 20th century is the polygraph. The polygraph is commonly known as the “lie detector” and given that name considering it is used frequently as an instrument to determine is someone is being untruthful. However, the truth is the polygraph is about as accurate as people. Though commonly called the “lie detector,” it turns out the polygraph is poor marker for judgement. The current body of work will explain the history of the polygraph and then show the current stance of the research on the polygraph and why it no longer has the proper placement as an instrument used for the detection of lies.


    Despite the early unsuccessful polygraph instruments invented (i.e. Mackenzie in 1905 & Marston in 1915) the modern polygraph is credited to John Larson in 1921, a student at the University of California. His underlying theory for developing this device is that people who were guilty would exhibit a physiological response, as where non-guilty people would not exhibit these responses. Larson later on came to question the reliability of the polygraph, especially its use in court.

    The lack of a common system to which the polygraph was implemented allowed different schools to implement their own methods and created many disciplines. In 1938, Backster created the Backster system that only used the scoring from the chart, which took the bias out of the examination by the observer. As a result, the spread of use of the polygraph spreading only increased and by 1939, Leonarde Keeler a protégé to Larson, developed the first portable polygraph that became marketable. This then lead into the Control Question Test that lead into the memorable line of questioning that we personify of the polygraph. By the 1960s the polygraphs and institutes that teach its method quickly spread to Japan’s, Israel, Korea, and China.

    PolygraafNew technology and methods only propelled the use of polygraphs that were rushed into law enforcement and used criminal investigation and sectors. The instrument that Keeler developed was the first the be purchased by the FBI and was the prototype for the modern polygraph. Keeler’s polygraph was even the first to be used in the police force in Chicago to take on the Al Capone war in Chicago. Other agencies such as the U.S. government in World War II used the polygraph to screen German POW’s. During the same time in the 1960s the private sector picked up the polygraph and employed its methods to the workforce. Employers used it to find “immoral behavior” and to determine criminal behavior. Coor’s in the 1960s used the lie detector as an entrance into the company asking questions such as, “What are your sexual preferences?” and “Are you homosexual?”, to trying trying sniff out moles to ruin their operation.

    More government appeal to the device continued in the 1970s insisting post-convection that used the polygraph as a deterrent to converted criminals and their behavior. Further government implementation of the polygraph continued into the 80s, when in 1983 Ronald Reagan affected 3.5 million using the polygraph to question people. This was because Ol’ Ron was “Up to his keister.” in leaked information regarding defense funding. By 1999, the government has once again relied on the polygraph to expose leaked information, this time from a Chinese spy at the Los Alamos Laboratory. The polygraph was ordered by the Energy Secretary, Bill Richardson, to be used on all the nuclear scientists. This was a move that was suppose to ease the public, but instead raised to question the legitimacy.

     Current Scientific Stance

    Due to the nature of the theory of the polygraph (i.e. lying creates anxiety and manifests physiological responses) and has gone wildly untested displaying unsettling evidence that has came to the polygraph. At this time there is a heavy split among the separate parties involved, those for the polygraph and those against the polygraph. Despite the polygraph supporters best intentions, the polygraph is quickly becoming less accepted.

    In the past decade or so the National Academy of Science (2003) and the Department of Energy for Congress (2007) remarked that the polygraph has weak scientific underpinnings. These are weak because the polygraph is questionable at best, it is often used as a the major evidence in court case when typically ignoring other scientific evidence. Examining through the vast studies reveled the polygraph accuracies rates to be around 80% accurate to no better than chance alone. This provides the polygraph a lack of consensus in its pseudoscientific community. Something such as global warming being caused by humans has an acceptance rate of 97% in the climatologist community.

    However, the polygraphs it is not a community just in despair, it is a community crumbling by lacking any scientific validation. The value, practicality, and reliability of the polygraph comes into question its usefulness and purpose. With the addition in new evidence showing the polygraph is a gimmick, an unreliable unreliable tool, and likely to brand innocent people as guilty. Even previously raved techniques such as post-convection where the polygraph has been used as a deterrent of certain behaviors has been found inaccurate and misleading. As a result of these recent findings the polygraph is quickly becoming less accepted by the scientific community for its effectiveness as a lie detector. While its impact is cumbersome, more should be done to phase out this antiquated technology as a teller of truths and lies.

    Category: PseudoscienceSkepticismTeaching


    Article by: Caleb Lack

    Caleb Lack is the author of "Great Plains Skeptic" on SIN, as well as a clinical psychologist, professor, and researcher. His website contains many more exciting details, visit it at www.caleblack.com