Polygraph technology is over a century old, but it’s one of the most useful innovations of the last 100 years. If you undergo polygraph testing today, it’s a very different experience from what it was in the early 1900s when it first debuted.

Today’s polygraph devices are software-driven, with examiners using laptops to monitor the examinee during the lie detector test. Compared to the old analog and paper systems of the past, they’re a technological miracle.

Let’s take a journey to the beginnings of polygraph science and look at the first lie detector machine and its journey through history.


Early Beginnings of the Polygraph

The first person to invent a scientific lie detector test was Caesar Lombrosso in 1995. Lombrosso named his invention “The Hydrosphygmograph,” which was a combination of a plethysmograph and a sphygmomanometer. It was the first device to analyze the examinee’s blood pressure and heart rate simultaneously under questioning.

However, this device wasn’t a genuine polygraph, as it failed to continuously read the examinee’s vital signs during the test. Lombroso was a criminologist who supposedly coined the term and worked with law enforcement on developing his device.

However, his Hydrosphygmograph didn’t receive global acclaim and fell behind in its development. Ironically, a Scottish medical practitioner developed the first Polygraph device, but not for the purpose of deception detection.


Dr. James MacKenzie – The Original Polygraph

Dr. James MacKenzie is credited for inventing the first device coining the name “The Polygraph.” MacKenzie was a trained cardiologist, working in Scotland before moving to England in the early 1900s. MacKenzie developed his “polygraph” to track a patient’s cardiovascular activity.

The device features two rubber tambours, in attached to the neck and the other to the wrist. The tambours would move in sync with the patient’s pulse, sending feedback down the rubber tubes to two scribing arms recording the movements using ink pens on chart paper.

MacKenzie introduced the polygraph in 1902, with it going into production between 1908 and 1910. While it was a breakthrough at the time, it was later replaced by the electrocardiogram machine (EKG). MacKenzie had no intention of using the device to detect deception; another doctorate from “across the pond” in America would first apply it to this task.


Dr. William Moulton Marston – The Systolic Blood Pressure Test

In 1915, William Marston, a Harvard Ph.D. student, got the idea to create a lie detector device after having a conversation with his wife, Elizabeth Marston. Elizabeth mentioned that she felt her blood pressure rising when she got excited or mad, causing her husband to investigate this theory.

Marston Graduated with an LLB in 1918 and a Ph.D. in 1921, debuting his “Systolic Blood Pressure Test” in 1915. Marston tried to get acceptance for his device in the law enforcement community and attempted to sell it to the US Army to interrogate German prisoners of war.

However, he never experienced success with his efforts. The closest he came was to attempt to use the results of his device as admissible evidence in a court case. In 1921, he used his Systolic Blood Pressure Test to prove the innocence of James Frye, an African American man accused of murder who confessed to the crime.

Marston claimed his interview with Frye proved that he was making a false confession about the murder. However, the court rejected the evidence provided by his device, leading to the District of Columbia Court of Appeals ruling on James Frye’s appeal in 1923 and dismissal of Marston’s work as evidence in the trial.

However, Marston did provide the inspiration for the world’s first polygraph device, invented by John A. Larson around the same time as the denial of his court application.


Dr. John A. Larson – The Sphyggy

John Augustus Larson gets the credit for creating the world’s first polygraph device. In 1915, Larson earned a master’s degree with his thesis discussing fingerprint identification. His work on forensic science led him to California, where he enrolled as a Ph.D. student at UCLA.

While studying toward his doctorate, Larson moonlighted for the Berkeley Police Department. It was here that he would encounter his mentor, Augustus Vollmer, the Chief of Police. Vollmer introduced Larson to William Marston’s work on the Systolic Blood Pressure Test, which fascinated Larson.

Larson was 31 when he invented the world’s first polygraph, nicknamed the “Sphyggy” by the media because they couldn’t spell or pronounce the word “Sphygmomanometer.” Larson’s device was the first polygraph to continuously measure three physiological responses: pulse, respiration rate, and skin conductivity. Essentially, his invention was a modification of the Erlanger Sphygmomanometer.

Unlike Marston’s device, Larson’s lie detector took continuous measurements of these vital signs, allowing him to get a more accurate view of the examinee’s responses under questioning. The first practical application of Larson’s device came in 1921 in the case of William Hightower, a man accused of the murder of a San Francisco priest.

Larson proved that Hightower was lying about his innocence, with the courts convicting him of the crime. Augustus Vollmer celebrated Larson’s invention, calling it a “lie Detector.” However, Larson didn’t agree with the title, referring to his device as a “cardio-pneumo psychogram.” Larson would later nickname his device “The Breadboard” polygraph.

Larson’s device was a huge success, with the media displaying its achievements in all major Californian publications the day after the test. While Larson gets the credit for creating the first official polygraph machine used in law enforcement and the title of “The father of the Polygraph,” his colleague, Leonard Keeler, gets the credit for making it a globally recognized technology.


Dr. Leonard Keeler – The Emotograph

When it comes to the creation of the first polygraph machine, many critics in the space argue that Leonard Keeler deserves the title, even more so than Larson. During Larson’s time with the Berkeley Police Department, he met Leonard Keeler.

Keeler was born in North Berkeley, California. Like Larson, he moonlighted at the PD while studying for his degree at the University of California in Berkeley in the fall of 1923. Keeler became intrigued with Larson’s device, assisting him with the early development of the Sphyggy.

However, he left the Berkeley Police Department in 1923 to follow Vollmer to Los Angeles after he was appointed Police Chief of the LAPD. He enrolled at UCLA while continuing his work on his and Larsons original lie detector device.

In 1925, Keeler debuted his new device, the “Emotograph.” The Emotograph was Keeler’s innovation of Larson’s original design. The issue with the Breadboard polygraph was that it was challenging to set up, requiring 30 to 45 minutes to prepare the device for an exam. Larson’s machine required smoke paper, which was cumbersome to set up, and required shellacking.

Keeler decided to replace the smoke paper with ink pens and chart paper, similar to Dr. James MacKenzie’s polygraph invented in the early 1900s. The result was a device that was easy to set up and easier to store the chart paper for further review in case analysis and evidence.

Amusingly, Police Chief Vollmer described Keelers Emotograph as “a crazy conglomeration of wires, tubes, and old tomato cans.” Keeler’s first use of his device was in a murder case, resulting in a confession from the suspect.

Unfortunately, his “Emotograph” prototype was destroyed in a fire in his apartment in 1925. However, Keeler’s success with his instrument provided him the motivation to continue with his work. Vollmer introduced Keeler to William Scherer of the Western Electro Mechanical Company, giving Keeler the resources he needed to redevelop his Emotograph.

Scherer built the Emotograph to Keeler’s instructions, encasing the device in a mahogany box for traveling. Keeler’s instrument was well received, and he sold 60+ units to law enforcement departments across America just a few months after starting its production.

The American Journal of Police Science interviewed Keeler about his invention, with Keeler describing it as follows.

“The apparatus consisted of 3 units, one recording quantitatively and continuously the pulse and blood pressure; another providing a duplicate blood pressure pulse curve taken from another part of the subject’s body and utilized for recording muscular reflexes of the leg or arm; a third unit records respiration.

The paper has a perforation on its edges and is drawn by the sprocket feeder roll, which is driven by a synchronous motor similar to those found in electric clocks. A differential gear train provides three speeds and is easily shifted by moving a small lever. A ninety-foot paper roll supplies the recording chart, with the curves recorded by a combined lever arm and fountain pen.

A dial-type sphygmomanometer is mounted on the panel, connecting through a 3-way valve to either blood pressure system, providing a means for determining the actual pressure in either system. The metal bellows or tambour stack constitutes the reproducing element of each unit, is mounted in a horizontal position below the panel on sliding runs, and is moved forward or backward (toward or away from the pivot shaft to which is attached the lever arm pen) utilizing a rack and pinion, which is controlled by a convenient knob on the panel.

The position of the tambour unit concerning the pivot shaft must be changed according to the pressure utilized in the system. The closed end of the tambour unit is kept at a constant distance from the pivot shaft. A signal magnet actuated by a push button at the end of a convenient length cord is mounted below the recording panel, and the connected pen marks the recording chart.

The whole apparatus is contained in a carrying case measuring 16 x 8 x 9 inches. All accessories, the lead to the 110v outlet, signal magnet cord, blood pressure cuffs, tubing, and pneumograph are carried in a compartment below the mechanism compartment; the instrument is portable and always ready for immediate use.”


Keeler worked independently of the LAPD but managed to deliver more than 30,000 lie detector tests using his device. In 1930, he moved to Chicago to take a position at the Scientific Crime Detection Laboratory at Northwestern University, becoming head of the organization in 1936.

Keeler kept redeveloping his device, teaming up with “Associated Research” in Chicago to design and produce Model #301, the first device to replace his redeveloped Emotograph.

HE would go on to design several other polygraph models, but many of the most successful instruments made under his name were produced well after he died.

Keeler eventually founded the Keeler Polygraph Institute in Chicago, where he worked until his death in 1949.


Dr. John E. Reid – The Father of Polygraph Questioning

While Larson and Keeler get the credit for designing the world’s first polygraph, it was John E. Reid that changed everything. Reid, a trained psychologist and police officer, redeveloped Keeler’s design in the 1950s, turning it into the “Reid Polygraph.” While it was an impressive innovation, Reid’s biggest contribution to polygraphy didn’t come from his device.

Reid was well known as a skilled interrogator and developed “The Reid Technique” for interrogating examinees. While some men, including Larson and Keeler, took an interest in developing the questioning side of the polygraph exam, Reid experienced the most success.

The Reid Technique involved a two-phase, nine-step process where the examiner first sympathizes with the suspect, then uses psychological tactics to get them to confess to their crimes. The Reid Technique was highly effective, becoming the gold standard of polygraph testing in the 1950s and 1960s.

It was so successful that the CIA contracted the training of its polygraph examiners, the Reid School before the organization formed its own polygraph training curriculum. There was plenty of controversy around the Reid Technique of coercing confessions from innocent men, such as the example of Darryl Parker, who Reid got to confess to a murder, but was later cleared of the crime.

However, despite the controversy, the Reid Institute remains the premier training destination for law enforcement and national security examiners. In 2013, a leaked document from the FBI showed the organization still using his Technique in polygraph suspect interrogations.