While many view Leonard Keeler as the “Father of the Modern Polygraph,” it was John A. Larson who inspired Keeler to create his technology. Without Larson, there would be no Keeler polygraph, and who knows what would have become of the technology without his early invention.

Larson was a true innovator, working on past deception detection methods to create the first device to detect deceptive behavior accurately. This post covers his life and work and how he changed the future of polygraphy.


The Early Invention and Advancement of Polygraph Technology

We must journey through history to understand Larson’s inspiration for creating his lie detector device. Several men before Larson passed the torch through the decades, building the foundational science enabling Larson to develop his lie detector prototype.

The earliest known references to using human physiology as a reference for lie detection come from the Spartans. Warriors coming of age would follow their masters to the cliff’s edge, where they stood on its precipice.

The elder would ask the warrior if they felt afraid. They would push them over the edge if there was any hesitation in their voice, casting them to their death below. Centuries later, in the late 1400s, the Spanish Inquisition would press their fingers against the throat of heretics, monitoring the changes in their pulse rate as they questioned them.

If the suspected heretic’s pulse increased under questioning, the inquisitors assumed they were lying, sending them to their death. These early references to deception detection laid the foundation for the evolution of polygraph sciences, with the following men building on this foundation with their work.


Sir Francis Galton (1879)

This English anthropologist and explorer developed a psychological test based on the assumption that guilty individuals suffer from internal conflicts affecting their speech. The test involves using irrelevant questions to establish a baseline response, then asking questions surrounding the issue to examine changes in their vocal response, indicating feelings of guilt.


Cesare Lombrosso (1895)

This Italian criminologist and anthropologist was the first man to develop an instrument supposedly capable of determining deceptive answers under testimony. He was the first scientist to experiment on suspected criminals outside the standard laboratory practice. He authored a book on the use of the “plethysmograph” and “sphygmograph” in deception detection, experimenting with electric shock stimulation. His device, the “hydrosphygmograph,” laid the foundations for Larson’s own instrument a few decades later.


Angelo Mosso (1895)

This Italian scholar ran experiments using plethysmography, studying how the fear response or “fight-or-flight” state affects heart rate and respiration in guilty individuals. He was the inventor of the “sphygmomanometer.”


Albert Stiker (1897)

This German scientist was the first to determine electrodermal activity changes while questioning guilty individuals during interrogations.


Max Wertheimer (1904)

This German researcher working out of the University of Prague was the first to combine word association into deception detection while recording physiological reactions on a hydrosphygmograph, plethysmograph, psychograph, and nomograph.


  1. Veragut (1907)

This Swiss scientist incorporated the use of word association with a galvanometer in deception detection. He coined the term “psychogalvanic reflex,” which later changed to “electrodermal response.” The electrodermal response measures the changes in conductance and resistance of the skin under questioning.


Dr. Hugo Mustenberg (1908)

Mustenberg was a professor of physiology at Harvard. He used word association to diagnose guilt in suspects. He was instrumental in the progression of deception detection techniques in American science.


Vittorio Benussi (1914)

This Italian psychologist was the first to incorporate the use of breathing patterns in deception detection. His pioneering work included monitoring the changes in the ratio of inhalation and exhalation during interrogation-induced stress.


Dr. William Marston (1917)

Marston was the biggest influence on Larson’s work. The man was a Harvard University psychologist developing a technique for measuring blood pressure in deception detection practices. He invented the first official lie detector device measuring systolic blood pressure.

Marston was also responsible for developing the first CIT and GN tests and was a polygraph examiner for the US High Court. While there would have been no Keeler if it weren’t for Larson’s work, there would have been no Larson if it weren’t for the work of Marston.


Who Was John Larson?

John Augustus Larson was born on 11 December 1892 in Shelburne, Nova Scotia, Canada. His parents were Swedish immigrants, moving to New England shortly after immigrating, but they divorced soon after that.

Larson studied biology at Boston University while taking odd jobs to support himself through his studies. He held positions as a paperboy, busboy, elevator operator, and stonecutter before graduating from Boston University in 1915 with a master’s degree in criminology, publishing his thesis on fingerprint identification.

Larson moved across the United States, settling in Berkeley, California. He pursued his passion for forensic science, studying at the University of California, Berkeley, obtaining a PhD. in physiology in 1920.

During his Ph.D. studies, Larson joined the Berkeley Police Department, as an intern, under the mentorship of Chief of Police August Vollmer. After completing his studies, Larson officially joined the Berkeley Police force in 1920. At the time, he was the first officer in America to hold an academic doctorate, using it to develop the first polygraph device used in criminal interrogations.

Larson based his work on the foundation laid by William Moulton Marston, advancing Marston’s work by measuring changes in blood pressure, pulse rate, respiration, and electrical skin conductivity, to design a lie detection device.

Larson was 31 years old and a medical student at the University of California when he developed his first lie detector prototype in 1923. He inspired Leonard Keeler, who would continue the advancement and development of his initial device in the 1930s.

Keeler and Larson worked together in the Berkeley Police Department, both relying on the mentorship of Police Chief August Vollmer in their early careers. When Keeler followed Vollmer to Los Angeles, the duo parted ways, with Larson entering the field of forensic psychiatry.

After one of the most famous careers in American criminal investigation, Larson died of a heart attack on 1 October 1965 in Nashville, Tennessee, aged 73.


The Pioneering Work of John Larson in Polygraph Technology

Larson’s interest in polygraph sciences came from studying the work of William Marston. Marston researched how a subject’s deception affects their blood pressure, using the discontinuous method to detect these physiological changes under laboratory conditions.

Larson studied the mechanics of instrumentation available at the time and their methodology, using it to develop his first prototype device. For his device, Larson selected to build on the foundation of the “Erlanger Sphygmomanometer,” modifying it to record changes in blood pressure using a smoked paper drum and a kymograph.

Larson published several papers on the performance of his instrument, taking care not to label it as a “lie detector” device. Larson stated he conducted his experiments to develop a new deception detection methodology rather than with the specific purpose of inventing a “lie detector” device.

Despite approaching his publications carefully, historians still view him as the inventor of the world’s first “lie detector device.”

There are divided opinions on Larson’s inventions. However, the popular belief is that Larson utilized two instrument designs during his early research into deception detection. He named his first device the “Cardio-Pneumo Psychogram,” consisting of a modified Erlanger Sphygmomanometer.

Larson relied on the expertise of Earl Bryant for the modifications, who worked under Dr. Robert Gesell at the Department of Physiology at the University of California. Larson borrowed an Erlanger Sphygmomanometer from Dr. Gesell, working with Bryant to modify the device to his requirements.

In 1921, Bryant manufactured another device for Larson, which was the final prototype used in investigations during Larson’s time with the Berkeley Police Department. Historians argue that the second instrument was merely a duplication of the first one developed by the duo.

This device drew Leonard Keeler’s attention, pulling his attention to the world of polygraph science. Larson named his device the “Breadboard Polygraph,” using it to measure examinees’ respiration rate, pulse, and blood pressure activity.

The Breadboard polygraph differed from Marston’s device in that it continuously recorded the subject’s physiological activity rather than the intermittent readings taken by Marston’s device. Larson also incorporated the use of an occlusion Sphygmomanometer Plethysmograph measuring blood pressure and blood volume in the test subject.

While it was a true innovation, the device had several flaws. For instance, it took the examiner nearly 30 minutes to set up and required the use of smoke paper to record the physiological responses of test subjects. The graphs produced by the device needed shellacking and storage in cans, becoming brittle and broken in many cases.

Despite its flaws, the device operated well, serving as the foundation for Keeler’s advancements of Larson’s technology during the 1920s and 1930s. Larson’s device worked using pens to scratch readings onto the smoke paper, recording the subject’s physiological data.

Over the following fifteen years, Larson collected data in criminal cases using his device, amassing hundreds of files where his Cardio-Pneumo Psychograph assisted in providing the police with supporting evidence in cases involving murder, robbery, theft, and sex crimes.

The media nicknamed Larson’s device the “Sphyggy,” writing stories on how his lie detector assisted the police with solving crimes during the 1920s and 30s. Larson’s original prototype now sits in the Smithsonian Institute in Washington, DC.


The Development of the Modern Polygraph Machine

During the 1920s, Larson teamed up with Keeler, and the duo continued the progression of Larson’s original device. Keeler was instrumental in refining the Sphyggy, Bringing in innovations such as doing away with the smoke paper and replacing it with chart paper and mechanical arms drafting the subject’s physiological responses in ink.

This single innovation made the device much more user-friendly, reducing the setup time and allowing for improved data storage. Keeler produced his first iteration of the Sphyggy in 1925, which he named the “Emotograph.” However, a fire at his home destroyed the first prototype of the device.

Since Larson never patented the Sphyggy, Keeler was the first American to patent a lie detector machine, filing for the patent in 1925 and receiving it in 1931. However, despite Keeler earning the moniker of “the Father of the Modern Polygraph,” Larson’s original design sparked his innovation with the Emotograph.


The Legacy of John Larson in Polygraph Technology

John A. Larson leaves behind a legacy positioning him as one of the biggest contributors to modern history’s improvement of criminology and criminal interrogation techniques. While Keeler continued his work, it was Larson who laid the foundations for the modern polygraph machine. Without Larson, it’s doubtful Keeler would have strayed into the field of polygraph science.

John Larson remains a pivotal figure in polygraphy, with his initial device being responsible for providing the evidence allowing police forces across America to remove thousands of criminals from the streets in the 1920s and 1930s alone.

During his time developing his prototype of the Sphyggy, Larson would test it on university students. It was through this practice that he met his wife, Margaret Taylor. Taylor was a freshman victim of the infamous “College Hall” case and the first test subject ever interrogated using his prototype device. The couple fell in love and married shortly after that.

Over the first 15 years after developing his first prototype, Larson personally conducted thousands of polygraph exams using his device. Eventually, he left police work to pursue a career in the field of forensic science, where he continued the practical use of his lie detector in cases.

The 2003 Encyclopædia Britannica Almanac lists Larson’s device as one of the top 325 inventions of all time. His device also gained much media and popular culture attention due to its success in the field. The Sphyggy even appeared in a silent action motion picture, “Officer 444,” in 1926.

It’s over a century since Larson introduced the world to polygraphy. It’s a wonder to imagine what he would think of today’s computerized software systems. While modern polygraph technology makes Larson’s device look like an antique, with the Sphyggy, they would not exist.