If we think of the evolution of the smartphone, it’s amazing to see how far the technology has progressed over the last 25 years.

While it’s truly impressive, the polygraph has a much longer history of development. If the founding father of polygraph science could see what their devices evolved into over the last 150 years, they would be awestruck with the progress of their original ideas.

This post tracks the timeline of the evolution of the polygraph. Let’s look at the inception of the original inventions and how they developed over time into the computerized systems we know today.


Early Beginnings – The 1800s

In 1875, Italian physiologist, Angelo Mosso, started his research on the relationship between fear and lying. Mosso’s studies proved the measurement of fear could extrapolate into a device capable of detecting lies.

The Italian realized that lying affects the pulse, blood pressure, and respiratory rate. This revelation led the researcher to develop his series of devices known as “plethysmographs.” His machines could measure changes in blood pressure and breathing, giving Mosso the first scientific method to determine if a person was lying.

His idea was simple. If he could observe these physiological changes in a person under questioning, he could prove they were feeling fear. The connection between fear and stress in the subject proved they were lying.


The Introduction of Electrodermal Response

In 1879, Dr. Marie Gabriel Romain Vigouroux, a French therapist, started researching the electrodermal response to lying behavior. He believed the subject’s electrical skin response changed under questioning when they were trying to act deceptively.

Dr. Vigoroux published his studies in an article in 1879, forming the foundation for further research. Boris Sidis, a Harvard psychology professor, performed a series of experiments in a paper called “A Study of Galvanic Deflections Due to Psycho-Physiological Phenomena.”

Sidis proved the relation between galvanic changes in the human skin and emotional responses. He presented his conclusions before the American Psychological Association at Harvard in 1909.


Cesare Lombroso – The Hydrosphygmograph

The first real breakthrough into lie detection in criminology came from Italian criminologist Cesare Lombroso in 1895. Lombrosso conducted experiments on criminals using his device, the “Hydrosphygmograph.”

This device measured blood pressure and pulse under questioning to detect deceit in a subject accused of a crime. In 1895 Lombroso published his work showing the use of a sphygmomanometer and plethysmograph when interrogating criminals.

It was remarkably effective, and seven years after presenting his work, in 1902, a device supported the process of proving a man’s innocence in a criminal trial.


Dr. James MacKenzie – The Original Polygraph

While Lombroso was working on his Hydrosphygmograph, Dr. James MacKenzie was busy developing the world’s first polygraph machine. MacKenzie, a Scottish-born cardiologist, built a device to simultaneously detect a patient’s cardiovascular activity.

His device continuously recorded the patient’s cardiovascular output and was the foundation for the development of the EKG machine. While MacKenzie didn’t build his instrument as a lie detector, Leonard Keeler would later use it to modify John Larson’s device, which we’ll get to in a minute.


Vittorio Benussi – Understanding Respiration

Italian Vittorio Benussi focused on analyzing suspects’ breathing under interrogation. In 1914, he announced he could detect a liar by analyzing the changes in respiration rate under the stress of questioning.

Benussi constructed the pneumograph to measure the subject’s inspiration/expiration ratio.” By dividing the length of inspiration by the length of expiration, he could detect when a subject was lying.


Dr. William Marston – The Systolic Blood Pressure Test

William Marston was a Harvard-trained lawyer and psychologist. One day, when talking with his wife, she commented on how her blood pressure would rise whenever she got angry. This observation led Marston to create a device that would measure changes in blood pressure, which he called the “Systolic Blood Pressure Test.”

Marston first used his device in 1921 to prove the innocence of a man in a murder trial. However, the court denied the admittance of the test results into evidence, leading to the formation of the “Frye” ruling. The Frye ruling would prevent the admissibility of polygraph results into trial evidence for nearly 70 years.

However, Marston inspired John A. Larson to design, build, and test the world’s first official polygraph device.


The Father of the Polygraph – John A. Larson

While all the previous men involved with the development of polygraph technology played a huge role in bringing about the lie detector, John Larson built the first polygraph used in law enforcement applications.

Larson was a Ph.D. student, moonlighting at the Berkeley Police department in the late 1910s. The Chief of Police, Augustus Vollmer, introduced Larson to Marston’s work, and Larson found it exciting. He went about building his first lie detector machine, which he maned “The Breadboard Polygraph.”

His device continuously measured the subject’s blood pressure, pulse rate, and respiration under questioning. His first use of his polygraph was detecting a shoplifter at a local campus, where Larson tested 38 subjects, with 37 passing the test.

Larson’s claim to fame for the Breadboard Polygraph came in 1921 when he successfully used the device to prove the guilt of a man accused of killing a San Francisco priest. The media covered the story the next day, calling Larson’s device the “Sphyggy” in their reports, and Larson’s work gained immediate notoriety in the law enforcement community.

The Encyclopaedia Britannia Almanac 2003 lists his lie detector as one of the 325 Greatest Inventions of all time.


The Adoption of the Keeler Polygraph

While Larson was working on his Breadboard Polygraph, he met Leonard Keeler. Keeler was also moonlighting with the Berkeley Police department while studying, and he met Larson through an introduction facilitated by Augustus Larson.

Keeler was immediately fascinated with Larson’s work, helping John build his first prototype. However, the pair split up when Augustus Vollmer moved to Los Angeles to accept a position as Chief of Police for the LAPD. Keeler followed Vollmer to Los Angeles, enrolling at UCLA while continuing to work on a modification of Larson’s original device.

In 1924, Keeler debuted his “Emotograph,” which was an improvement on Larson’s design. The device used chart paper and ink pens to replace the smoke paper used in Larson’s model. The result was a faster setup and easier chart paper storage, as evidence.

Keeler lost his original prototype of the Emotogrph during a fire at his apartment in 1925. Vollmer introduced Keeler to William Scherer of the Western Electro Mechanical Company, and the pair would collaborate on rebuilding Keeler’s new device to his specifications.

Keeler used the Emotograph in thousands of polygraph exams over the next decade. Possibly the case that drew the most attention to his new device was the 1937 investigation into Francis Sweeney, the prime suspect in the Cleveland torso murders.

Keeler’s device showed Sweeney lying during the polygraph exam. However, he was not convicted in court due to a lack of evidence and the Frye legislation we mentioned earlier blocking the polygraph results from being definitive evidence in the case.

Keeler then took a post at the Scientific Crime Detection Laboratory at Northwestern University in Chicago in 1930. In 1930, he received a patent for his lie detector device. He collaborated with Associated Research, a local firm, to build his Keeler range of polygraphs, starting with model #301.

By 1935, Keeler had already conducted more than 2,000 polygraph tests. The 301 included the first use of Dr. Vigorouxs theory on skin conductance in the device, adding another parameter to his polygraph to further enhance its accuracy, the psycho galvanometer.

In 1947 Keeler established the Chicago-based Keeler Polygraph Institute, the first polygraph school. He died in 1949 at age 45, after health complications involving his excessive use of alcohol and cigarettes after his wife left him and later perished during military service.

Despite Keeler’s death, Associated Research continued manufacturing various models of the Keeler polygraph up until the late 1960s. His polygraphs were so successful that the CIA used them during the Korean War to uncover Chinese double agents and during the Cuban Missile Crisis to uncover Cuban nationals suspected of terrorism against the United States.


John E. Reid and the Advancement of Polygraph Questioning

In the 1940s, many other companies like Stoelting jumped on the bandwagon, producing polygraph devices. However, the most notable man in polygraph science in the wake of Keeler’s death was John E. Reid. Reid was a lawyer, psychologist, and police officer based in Chicago. He redeveloped the Keeler polygraph to his specifications, creating the Reid Polygraph.

While his polygraph device was a notable advancement of the technology, including bellows to measure movement, his biggest contribution came from the development of “The Reid Technique.” This questioning technique, also known as the “Control Question Technique,” came about in 1945, featuring a two-phase strategy where Reid would use a 9-step process in interrogating suspects during criminal investigations.

The Control Question Technique (CQT) and the Reid Technique became the industry standard for interrogating suspects due to their high success rate at getting criminals to confess to their crimes. However, it wasn’t without controversy.

In the 1950s, Reid used his technique to coerce a confession from Darryl Parker, which Parker later recanted, stating the pressure of the test caused him to make a false confession.

Despite this controversy and many others like it, the Reid Technique was a huge success, becoming the benchmark standard in interrogation questioning for the CIA, DOD, and FBI. These organizations sent hundreds of examiners to the Reid School for training before eventually forming internal training schools for their examiners.

However, many employees and operatives within national intelligence complained that the change in polygraph questioning brought about by the adoption of the Reid Technique caused false positives. Despite these acquisitions, a leaked document from the FBI in 2013 shows the organization still uses the Reid Technique in its polygraph exam process.


Cleve Backster – Quantified Chart Analysis

Cleve Backster was an ex-CIA polygraph examiner who introduced the concept of quantified chart analysis, which would inspire the digital revolution of the polygraph. His method used numerical analysis to achieve reliable polygraph exam results.


The Era of the Computerized Polygraph

In the late 1980s, scientists from the University of Utah invented the “Computer Assisted Polygraph System” (CAPS). They used algorithms to interpret the physiological data sent to them by the instrumentation worn by the examiner during the test.

Research into computerized systems continued, with Axciton Systems partnering with John Hopkins Laboratory to create the PolyScore system and the Stoelting company partnering with John Kircher and David Raskin at the psychology laboratory at the University of Utah in 1988 to create the CPS system.

The introduction of algorithms to polygraph science changed the game, and as computer technology became more advanced, it improved polygraph exam accuracy. Many companies, including Axciton Systems, Stoelting, Limestone Technologies, and Lafayette Instruments, started a race to see who could produce the best polygraph software.


Toward a New Future – Polygraphs & AI

While the computer revolution saw polygraph technology increase by leaps and bounds, it pails compared to what artificial intelligence (AI) has in store for the industry. AI tools are already here, with the US Government collaborating with Canada and the EU in a program designed to bring this tech to market.

The US provided the training ground for the Israeli AI platform “AVATAR,” which uses a mix of voice stress analysis and facial microexpressions to detect deception in travelers visiting the United States. The pilot project, launched in 2011 through 2012, was used in a kiosk to detect immigrants arriving in the United States.

The European version, “iBorderCtrl,” was a pilot launched in 2017 and 2018 in various EU countries, relying on the same technology. Both projects proved successful in the pilot stages, providing accuracy rates ranging from 60% to 85%.

Integrating these AI systems into customs and border control processes was to reduce the human resources required to question and inspect travelers. With the technology still in its infancy, we can only imagine what AI has in store for polygraph science in the future.