9/27/2022
In today’s strange science video, we’re going to look at the lies of the ‘science’ of polygraphy, a.k.a. lie-detector testing. And how from a scientific standpoint it’s absolute bullshit, yet in practice strangely works in some situations. This is part of a series of videos where we examine different hypothesis & theories to determine if they are science or pseudoscience.
Citations:
Popper, Karl Raimund. Conjectures and Refutations: The Growth of Scientific Knowledge. 1963. Buy here!
Popper, Karl Raimund. The Logic of Scientific Discovery. 1934. Buy Here!
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We’re going to look at the lies of the ‘science’ of polygraphy, a.k.a. lie-detector testing. And how from a scientific standpoint it’s absolute bullshit, yet in practice strangely works in some situations.
First off, what exactly is a polygraph test & how does it work? The polygraph test was invented in 1920, by John Larson who graduated Berkeley University with a Ph. D in physiology. A polygraph focuses on three physiological indicators: heart rate/blood pressure, respiration, and skin conductivity. When most people lie or do something wrong, they usually feel some type of physiological response: your heart might feel like it’s sinking, you feel a knot in your stomach, you may feel a type of revulsion, or hyperventilate. Furthermore, all people have unique unconscious physiological expressions that occur when a person is stimulated. With regards to deception, we’d say a person has a tick or a tell that shows they’re being deceptive.
It’s these types of assumptions that might serve as evidence that some type of physiological test could accurately determine when a person is lying. But, here’s the problem: there’s no real evidence that any pattern of physiological responses are unique to lying. Ticks are typically unique to every person. Someone who is extremely nervous may test negative when being truthful, and a dishonest person may have no anxiety whatsoever. And then there’s people like me who are anxious all the time!
Beyond the theoretical problem that we aren’t able to determine a valid pattern of physiological responses, psychologists and scientists agree there is little, if any, validity in the results of lie-detector tests. The United States Supreme Court has repeatedly rejected the use of polygraph data in court rooms citing unreliability. In 1988, the U.S. Congress passed the Employee Polygraph Protection Act, prohibiting private employers from using the machine to screen employees, though public employers can and still do use polygraph testing in their hiring practices. In 2003, the National Academy of Sciences and the National Research Council concluded in a report that “the scientific evidence supporting the accuracy of the polygraph to detect deception is intrinsically susceptible to producing erroneous results.”
Remember that guy John Larson, who invented the machine? Even he came to reject the test and inventing it was one of his biggest regrets. Larson found through his own research that results were inconclusive nearly 40% of the time. Larson remained a scientist, adopted the critical attitude, and falsified his own invention rightly when the evidence falsifying the tests appeared. Larson wrote in 1965, shortly before his death, “Beyond my expectation, through uncontrollable factors, this scientific investigation became for practical purposes a Frankenstein’s monster, which I have spent over 40 years in combating.”
Despite all this, polygraph tests are still widely used in a number of different circumstances. Why? Despite living in a regime of truth constituted on science, how are pseudoscientific forms of knowledge still able to function, still able to have scientific authority, and circulate in society as a truth?
Polygraphy was invented as a police investigatory practice. John Larson was also a police officer for the Berkeley Police Department way back in 1920. Both a police officer & a doctor. Is he officer dr, or doctor officer? I like Doctor Officer better.
So, Doctor Officer Larson had a protege named Leonarde Keeler who was deeply fascinated with Larson’s inventions. However, unlike Doctor Officer Larson, Keeler was not a scientist. He marketed the polygraph tests. Keeler couldn’t patent the polygraph tested because he didn’t invent it. But he did invent the dominant way of interpretating the “data” provided by the machine. Keeler became a consultant selling his services and training people in the appropriate methods to use the machine.
Despite rarely being allowed in courtrooms throughout its entire history, the polygraph test is still widely used by law enforcement to this day. And, in many, many cases, criminals do confess to crimes during or after a polygraph test that they actually committed. But, is the reason this occurs because the lie-detector test actually detected deceit, or is it merely a placebo effect caused by the entire process of engaging in polygraph testing?
Most people know very little about physiology, or the pseudoscience of how the machine works, or the myriad problems we’ve gone over so far.
Many of us grew up watching shows like Maury Povitch, Dr. Phil, and the Jerry Springer show if your parents weren’t there. These shows frequently polygraphed alleged cheaters, spurned lovers, miscreant juveniles, and all other manner of people in crisis who could be commodified. This gave many of us the belief that the LIE-DETECTOR TEST could detect lies.
A person hears LIE-detector, remembers that hilarious moment on TV, and accepts the scientific authority of the polygraph test.
Let’s look at a test case to show the severe heuristic errors, bias, and placebo effect of the “so-called lie detector test.” Heuristics is the study of different methods and models of scientific inquiry.
This is the story of Christopher Lee Watts. Watts is a family annihilator, who in 2018, strangled his pregnant wife before smothering his two daughters. When his family initially went missing, Watts claimed he had no idea where his family was, insinuating that his wife Shanann had run off or they had been kidnapped. Watts went so far as to do a interview with the local media begging for his family’s swift return.
Literally, almost everyone, believed Watts had something to do with his family’s disappearance from the very beginning. However, all of the evidence pointing towards him was circumstantial at best, and was insufficient for a judge to issue an arrest warrant. Law enforcement either needed to find Shenann and their daughters, or they needed to get Watts to confess.
After several hours of interrogation where police were clearly insinuating that Watts was guilty while Watts denied any involvement, a detective asks Watts if he will take a polygraph test. Watts accepts.
The next day, Watts returns to the same interrogation room as before, but now with a polygraph testing unit present. Watts is introduced to a woman named Tammy who is the polygrapher. Of course, Watts doesn’t know she’s also a detective who has a vested interest in Watts confessing. If this were a legitimate scientific test, the polygrapher would be someone completely neutral.
It should be noted, that the police are legally allowed to lie to you. Specifically, the United States Supreme Court ruled in the 1969 case Frazier v. Cupp, that police are allowed to use deception as an investigative tool. Officer’s will often lie to suspects hoping to throw a suspect off. They may say that a suspect’s friend has already confessed and blamed everything on the suspect; or, that the DNA test came back positive. Even if these things are not true, it may trick the suspect into confessing.
In the American crime drama television series, The Wire, there’s a scene where a young, naive suspect agrees to a polygraph test.
In case you didn’t notice, that is not a polygraph test; his hand is duck-taped to a copy machine.
Back to the Watts case, Tammy the Polygrapher quickly begins listing a number of alleged accomplishments that show her prowess and authority in discerning truth from deception. Even if these accomplishments are true, with the pseudoscientific nature of polygraph testing it’s about as useful as being certified in phrenology, or eugenics, or psychoanalysis. Tammy then performs a pre-test where Watts is asked basic questions and is told to answer falsely to some of them. This is allegedly to get a base line reading for Watts when he’s telling the truth or not. At the end of this, Tammy tells Watts that he is a really bad liar, and describes his baseline false statement as extreme. This technique is known as the “stimulation test” and can be found in a 1997 textbook given to Department of Defense Polygraph Institute examiners. “DO NOT show the test to the examinee,” the book instructs, “but convince the examinee that deception was indicated.” After administering the test, the examiner is to describe the results to the subject.
Of course, Tammy never actually shows Watts the raw data showing this, but even if she did, Watts would have no real way of deciphering the data. This is a philosophical problem that comes from observation. Both Tammy and Watts can look at the same reading that is basically just a squiggly line and see completely different things. A big part of scientific observation involves the eye being properly trained to know what to look for. Even though polygraphy is pseudoscience, in order for its truth’s to function and circulate requires a specific type of training for the polygrapher on the proper interpretation of said squiggly line.
Watts takes the polygraph test, and after what I’m sure was a careful and thorough reading of the squiggly line and presumably some tea leaves, surprise surprise, the police determine that the person they believe is guilty “failed” the polygraph test.
Again, they don’t show Watts any of the data confirming this, but they use strong declarative statements of the futility of arguing with “science.” Let’s pretend polygraph’s actually are accurate at detecting deception (they aren’t, but it’s fun to imagine). The only way this testing could be conceived as anything remotely scientific is if 1) the polygrapher were a truly neutral party; 2) the polygrapher does not provide any extraneous information unrelated to how the testing is performed and the expectations of the suspect; 3) the polygrapher did not comment on the suspect’s baseline prior to the test; and 4) the results are provided to both the police and suspect without police influencing the result.
Of course, Watts actually was being deceptive during his polygraph test.
Watts did in fact murder his entire family, and he is a lying sack of shit. Watts did eventually confess everything, and he will spend the rest of his life in prison. However, it’s highly unlikely that even if the test reported those statements as false, that this is not mere coincidence. Furthermore, there seems to be no way to tell whether it is the polygraph result itself that leads to confession or merely a placebo effect caused by the authority the polygrapher is believed to have.
The final question we need to answer is whether you should ever agree to a polygraph with law enforcement? And, that answer is definitively no! Even if you “pass” the test, it’s not as if you could use it to your advantage at court because, again, it’s inadmissible because it’s bullshit. Let’s go back to Chris Watts. Right here, when he’s told he “failed” the test, he was still legally allowed to leave. Despite all the circumstantial evidence, police still did not have enough probable cause to get an arrest warrant, because, again, the polygraph test is not legit. Watts made three mistakes: Mistake 1) he murdered his entire family (seriously dude, dick move); Mistake 2) he didn’t have a lawyer present during his interrogation; and Mistake 3) he agreed to a polygraph test. Don’t be like Watts.
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