One of the most desired superpowers is to guess what others think. Fiction has fantasized a lot about it, and even science fiction has considered the possibility of creating apparatus or machines capable of translating brain waves into real images. And if we talk about reading minds, one of the main reasons is to know if the person we are talking to lie to us or tell us the truth. Here fiction has also made the fantasy of guessing whether or not we are being lied to reality. Series such as Lie to Me (2009-2011) theorized about reading facial expressions to detect lies. But it would be better to have a machine that simply tells truth or lies, a polygraph, truth machine or lie detector.
If we have a machine that makes toasts and another that heats food, why can’t we invent a polygraph? A machine that tells you whether or not that person speaking is lying. A dream come true. Or at least, on paper. So attractive is the idea of detect lies in seconds that movies, series and television shows have used the truth machine for decades. Even today it is used, both in the televised entertainment like in police trials and investigations. However, science is not so much in agreement with which the human being has created a machine of the truth. This is his story.
Policemen and inventors, the origin of the polygraph
Inventions generally arise out of necessity. And in the case of the polygraph, the technical name by which we know the popular truth machine or lie detector, the need was catch the person responsible for a crime. Or put another way, convict the offender when there was no evidence available or a signed confession. Something that would save effort, hours of work and taxpayer money. Furthermore, it would avoid imprisoning innocent citizens.
Leonarde Keeler testing her lie detector on Dr. Kohler, a witness in the trial of Bruno Hauptmann in 1937
The parents of the polygraph were two Americans: John augustus larson and Leonarde Keeler. The first was a part-time employee of the Berkeley, California, Police Department. The second, he started as a deputy at the Berkeley Police Department, where he went on to help Larson. In time, Larson would dedicate himself to forensic psychiatry, after studying medicine, but always linked to his polygraph. Keeler went to college and thereafter moved to Los Angeles with his mentor, Police Chief August Vollmer. Two successful careers. But let’s go in parts.
John larson He was born (1892) in Canada to Swedish parents. He spent his childhood in New England, so he ended up studying his university studies at the Boston University. Specifically, he studied biology. After obtaining a master’s degree (1915) with his thesis on fingerprint identification, Larson’s academic career went this way. From Boston he traveled to Berkeley, where he obtained a doctorate in physiology from the University of California (1920). Larson worked part-time at the Berkeley Police Department under the command of the Chief of Police during his Ph.D. August vollmer.
During his time at the Berkeley Police Department, Larson was clear that he wanted to combine elements more typical of a medical examination to use them as a lie detector. These were blood pressure, pulse, respiration, and skin conductivity. Larson believed that reading these parameters would yield the long-awaited answer: was someone telling the truth or was he lying?
In this task, Larson was not alone. He was accompanied by a young high school student, Leonarde Keeler, who worked part-time for the Berkeley Police Department, also reporting to Police Chief Vollmer. So Keeler became Larson’s assistant.
The first cases of the truth machine
The first machine they created was called cardio pneumo psychogram. An unattractive but very explanatory name, since it took into account the heart and breathing indicators to get the answer to the question: truth or a lie? But soon they changed the name to polygraph, which better condensed what that strange machine did. The machine took into account blood pressure and heart rate while being questioned. If they were nervous, the machine showed it on a roll of paper where the metrics were represented graphically.
Larson’s theory was that a liar showed physiological responses different from who was telling the truth. Hence the key to nervousness. His logic was: if someone lies, they will be nervous when asked by a police officer. Thus, the machine will register that nervousness, which translates into alterations in blood pressure, respiration and pulsation.
However, over time we have learned that this is not always the case. An innocent person can be nervous for many reasons, one of which is being charged with a felony. When questioned, even if she tells the truth, her nervous behavior can give the same response as someone who is nervous about lying. But in 1921, which is when the machine began to be applied in forensic practice, the idea seemed good, and the science had not advanced enough to refute the premise of the lie detector.
Keeler polygraph model 6317. was used in December 1963 in the case of Jack Ruby, who shot Lee Harvey Oswald. Source: FBI
In the summer of 1921, the truth machine received its first case: the murder of a parish priest in San Francisco. The defendant, William Hightower. Interestingly, the police were not in charge of using Larson’s polygraph. Instead, it was a newspaper of the time, The San Francisco Call and Post, who commissioned Larson. Hightower allowed the polygraph test to pass but sadly the results were damning. Or at least that is what said newspaper published on the front page. August vollmer, Chief of Police of the Berkeley Police Department, put out his chest before the press and covered in praise that strange machine called cardio pneumo psychogram or polygraph but which he baptized as lie detector.
Larson and Keeler’s path followed separately but in parallel. Both dedicated to using their machine to solve crimes. Keeler, for example, studied at University of California and then in the angelina UCLA. As an inventor, he continued his career improving the truth machine. Funded by the Western Electro Mechanical Company, created the first mass-produced polygraph. And he found a major buyer. Nothing more and nothing less than the FBI, one of the most important federal agencies.
Keeler’s polygraph was used in a trial for the first time in 1935. Specifically, it was applied to two defendants of robbery in Portage, Wisconsin. The results of the machine were provided as evidence and the trial ended up condemning the accused.
In time, Keeler would end up working in the Crime Detection Laboratory of the Northwestern University. Later he would create his own academic institution, the Keeler Institute, the first school where the use of the polygraph was taught.
A machine to detect what?
Polygraphs did not cease to be originally blood pressure gauges. The same could be used for a medical check-up or for detecting someone’s nervousness. And although they were evolving, detecting more elements such as skin conductivity (1931) and incorporating computer science and electronics to replace paper, the initial premise remains the same. As we saw before, the truth machine did not detect lies, it detected nervousness. And the nerves, for now, are not constitutive of crime.
Today, the lie detector is considered pseudoscience by scientists and institutions such as the United States National Academy of Sciences or the American Psychological Association. Nevertheless, in popular culture it got very strong the idea of the polygraph. The press of the moment and, later, fiction series and films, gave this invention a lot of fame.
To the extent that it is used interchangeably in television entertainment programs and in trials in some countries such as United States or Canada. In Europe, Germany and Holland scrapped its use in 2017. BelgiumFor his part, he uses it in police investigations but not in trials. And in Spain, has had more relevance on television than in forensic science, although it has also been used in some police cases.