• 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

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    • ke Liu

      micro expression could perform better than polygraph.

      • Kiersten Durning

        I agree that micro – expressions would be interesting to look into. Personally I’m a fan, but they would have to record the individuals and then analyze frame by frame. I’m not familiar with how long it takes to analyze a polygraph but imagine it would be faster.

        • kellyjent

          I agree too. Have you seen the show “Lie to Me”? It’s about a psychologist who specializes in body language – specifically micro-expressions. Anyway, it’s really interesting. However, analyzing micro-expressions would be pretty subjective, and while if done correctly it may work well, I feel at this point (trying to move away from a polygraph) the more objective a measure used, the better. What that could be though, I have no idea.

          • Kiersten Durning

            Yes I have, it’s loosely based off of Dr. Paul Ekman who is a leading researcher in micro – expressions/ emotions. I’ve read several of his books on emotions and deception. That show is entertaining but exaggerated. However, if you remember their “lab” with all of the screens displaying the frames? That’s what I was talking about with analyzing micro – expressions. Many of the images were from Ekman’s programs that he developed. He was actually the “scientific go to guy” for the show since the main character was loosely based off him. Also another fun fact, the girl who played his daughter in the show is my friend’s little sister. She went to my high school with us before she dropped out for Hollywood.

        • CatherineD

          I agree, micro-expressions are so fascinating. Unfortunately, unless they found a different way to observe it, it would be subjective and extremely susceptible to error, not to mention time-consuming.

          • Kiersten Durning

            With the use of facial EMG and multiple analysis… I would argue it’s no more subjective than a polygraph would be. But yes, as I said in my first comment I would also have to agree it would be time consuming.

        • ke Liu

          The excellent work by some psychologist indicated that a well training person could identify the micro-expression in a few second, and people can’t conceal micro-expression even if under conscious condition. However, the well training agent, let’s say an FBI agent like James Bond, may control the frequency of breath or the heart beat, which can deceive the polygragh.

    • J. Kyle Haws

      When ever my mom thought I was lying she made me look deeply into her eyes and every time she concluded that I was lying. Even though I may have been telling the truth. Her reasoning was that I seemed anxious. It never occurred to her that I was anxious because she was grilling me and forcing me to look her in the eyes. In the same vein, It is surprising that unreliable tools and techniques were used to determine if someone is lying.

      • CodyB

        I chalk it up to people loving machinery. The idea that a little box with a swinging arm can detect the true intentions and history of a person is very tantalizing.
        God help us if they make one that actually works…(or looks even cooler)!

    • Kaitie McElroy

      It is interesting how quickly technology can get rushed into main stream use without proper testing. Especially a technology with so many lives ridding on it, imagine how many people had their lives ruined or were put in jail as a result of “failing” the polygraph.

      • Kylerdean

        One has to wonder how to properly test a polygraph due to the many factors that can influence a false reading. Not only is testing needed for these advancements in technology that are rushed into main stream but it needs to be understood that people have learned how to pass a polygraph or loop holes that even though they are guilty they are able to pass. Society needs to realize that, yes a polygraph is a quicker way to prosecute someone, but it may not be the best when sticking to scientific facts.

    • hellokitty69

      Polygraphs are a great example of how wanting the truth often supersedes the effectiveness of the means of obtaining it. Although it is now recognized as ineffective (as a “lie
      detector”) and mostly used by police to rattle suspects, it has undoubtedly
      played a part in imprisoning innocent people. It’s simply another eyewitness
      whose account of events is questionable at best. As it becomes more broadly
      exposed as a pseudoscientific and counterproductive tool, hopefully its use
      will be curtailed by law enforcement. This post has a lot of solid sources.


      Very interesting stuff here. I did a quick internet search for “how to beat a polygraph” after reading your post, and I was surprised at how apparently easy it is to throw the readings off just enough to call the whole test into question, even among those who believe the polygraph is fairly accurate. Well heck, if it is so darn easy, that really highlights just how unreliable it is from the start.

    • Lauren Gaudreau

      Have they done any research on criminals who have been wrongly convicted via a polygraph? Or people who may have not received a job due to these machines? Being in the forensics field, I often think about these things. I try to steer clear of any actions or activities that could put me in jeopardy for a potential job, but I know for a fact most government agencies use polygraphs to assess their potential employees. Scary thought for the future :/

    • Christina Smith

      Interesting blog post. I have always been against using a polygraph as a way of getting information out of someone. If someone gets an uncomfortable question or is just nervous anyway, they are automatically lying. I noticed some other comments mentioned micro expressions – which I’ve never heard of – but I’ll be looking in to it!

    • Carrie Tubbs

      It is amazing how something that our society relies on so often has no scientific validation. You would think if we are putting someone in jail based on these kinds of results, that we would be thinking enough to make sure that it actually works. There is a TED talk about a new and upcoming procedure that leads scientists to believe they can read your minds by the activation of certain brain areas. There was talk of it being used criminally for courts, but just like the lie detector, I’m unsure of its validity.

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