The polygraph had a huge impact on the modern world. From its development in the late 1800s, this device changed the field of law enforcement interrogation. It went on to have many uses in the private and public sectors. Its world-changing applications impacted society so much that it became one of the top 325 inventions of all time listed by Encyclopedia Britannica.

Today, the polygraph device has many applications, and it’s a sought-after technology involved in several industries. While some experts state the lie detector is a flawed device yielding questionable results, others say it detects deception accurately.

With the integration of AI into polygraph science, we expect the technology to continue to find many uses in the future. This post looks at the development of polygraph devices, the people responsible for bringing them into existence, and the first uses of lie detectors. We’ll also look at modern applications of polygraph science and where we think it’s going in the future.


Who Developed the Polygraph? – A Progression in Technology

The modern polygraph is a result of the work of several men throughout history. During the late 1800s, individuals like Cesare Lombroso and Vittorio Benussi discovered the effects of lying on the cardiovascular system, using this information to craft devices capable of monitoring these changes under questioning.

However, four men had the biggest influence on the creation of the modern polygraph. Let’s look at each of their individual contributions. The exercise helps us form a roadmap to the development and integration of polygraph technology into private and public sector applications.


Sir James McKenzie

Dr. James McKenzie was a Scottish-born cardiologist born in the mid-1800s. He received his medical degree from the University of Edinburgh in 1882, practicing medicine in Burnley, Lancashire, for over a quarter of a century.

His work, “The Study of the Pulse,” published in 1902, drew attention to his device called “the polygraph.” This instrument allowed McKenzie to distinguish between pulse irregularities. McKenzie developed his device in collaboration with Sebastian Shaw, a Lancashire watchmaker.

The instrument relied on a clockwork mechanism for its time-marker movements and paper-rolling, producing ink recording of cardiac responses made by individuals under questioning. This device formed the foundation of the modern polygraph, with three men taking up the mantle of progressing his work.


William Marston

Dr. William Marston, a psychologist, and attorney, was the first American to establish himself in polygraph science. Marston studied McKenzie’s work, adding his own take to the technology. In 1915, Marston developed the “discontinuous systolic blood pressure test.”

He would use his research to develop a lie detector device, becoming one of the key components of the modern polygraph. Marston’s technique involved using a blood pressure cuff and stethoscope to record intermittent systolic blood pressure readings of suspects involved in criminal cases.

However, Marston didn’t dedicate himself to the progression of the device, despite his invention being used in many criminal cases. In Fact, Marston’s early work in polygraphy led to the “Frye” legislation, where courts refused to admit polygraph results as admissible evidence in criminal cases.

This legislation still stands today, despite the massive improvement in polygraph technology since the development of Marston’s original device in the last century.


John Larson

Possibly the biggest influence on the progression of polygraph technology comes from John A. Larson. Larson was a Canadian-born psychologist trained at UCLA and Stanford in California. During his early research, Larson found himself studying Marston’s work with the goal of improving on his original design.

Larson achieved this goal by bringing his first lie detector, the “Sphyggy,” into law enforcement interrogations in 1921. Larson moonlighted at the Berkeley Police Department while studying at UCLA. His invention simultaneously measured blood pressure, pulse rate, and respiration, bringing several factors into the polygraph for more accurate readings.

The device recorded these physiological changes in suspects under questioning, recording the data of sheets of smoked paper. The device proved remarkably accurate, catching the attention of Leonard Keeler.


Leonard Keeler

In the 1920s, Leonard Keeler started working at the Berkeley Police Department alongside John Larson. Keeler found himself fascinated by Larson’s work, assisting him in advancing the technology of the Sphyggy. Keeler improved the device, doing away with the need for smoked paper, allowing for faster polygraph setup and better data storage.

Keeler modified Larson’s original design, naming his first prototype the “Emotograph.” Unfortunately, this device was damaged beyond salvage in a fire in his apartment in 1925. Keeler continued his work, teaming up with scientists to produce another Emotograph, and saw huge success with its use in law enforcement applications.

Keeler continued to progress his original design and, in 1938, added the feature of a psychogalvanometer to measure the examinee’s galvanic skin resistance under questioning. The result was “The Keeler Polygraph.”

Keeler died in 1949 after suffering a stroke. However, “Associated Research,” a Chicago technology firm, continued developing several progressive models of the original Keeler polygraph, including the “Pacesetter Series,” which would dominate the polygraph market until the 1990s.


What Were the First Uses of the Polygraph?

The polygraph has several uses today. This device has incredible utility, and its original use was to detect “deceptive” behavior in people. This remains the primary function of the polygraph today. It’s a highly effective device capable of helping examiners understand the physiological behavior of people under questioning.

The polygraph works by monitoring changes in blood pressure, respiration, heart rate, skin electrical activity, and sweat gland response under stressful situations, such as interrogations and questioning. When people lie in a stressful environment, it activates the “fight-or-flight” response, causing elevation of their vital signs, which an examiner interprets as a deceptive response.


Criminal Investigations

The original use of the polygraph was to detect deceptive behavior in suspects under criminal investigation. Larson and Keelers’ work with the Berkeley Police Department gave them ample opportunities to implement and refine the polygraph in criminal questioning.

Over the decades between 1920 and 1930, Larson and Keeler administered thousands of polygraph tests to suspected criminals. Thanks to their work, the polygraph helped remove thousands of criminals from the streets, making American society a safer place.

The Keeler polygraph received widespread adoption in police departments across America and around the world. It became the benchmark standard of equipment used in interrogation processes in law enforcement scenarios.


Employee Screening and Assessment

While the polygraph was first used in criminal investigations, it wasn’t long before Keeler introduced it into the private sector. The polygraph accurately detected deception in any individual with something to hide. As a result, companies across the United States started using polygraphs in candidate and employee assessments.

Organizations in the private sector found the polygraph useful in assessing new candidates for employment. They could determine if the candidate presented a threat to their business. For instance, if the employee had a criminal history or ties to criminal organizations, that might defraud or rob the company.

The polygraph was so effective at these applications that many employers started abusing it in their employee hiring and firing practices. By telling a candidate they failed the polygraph, they could eliminate people they found undesirable from working in their business, such as certain ethnic groups.

However, Ronald Reagan put a stop to the use of polygraph testing in employment practices by signing “The Employee Polygraph Protection Act” (EPPA) into power in 1988. Today, private sector companies must have good reason to implement polygraph policies in the workplace.


Government Organizations

The polygraph was so effective at detecting deception that many government organizations adopted it as part of their hiring and firing practices. The CIA, FBI, and DOD incorporated polygraphs into their HR practices and other applications, such as questioning suspected terrorists.

The introduction of advanced questioning techniques, such as “The Reid Technique,” developed by John E. Reid in the 1950s, made the polygraph more accurate at detecting deception. The Reid technique involved a specific three-stage questioning process adopted by local and state law enforcement and organization like the CIA to question suspects.

However, the Reid technique was so effective at coercing confessions from suspects that it resulted in many false confessions and convictions. As a result, many European organizations using it decided to do away with it in the 2010s.

Public-sector organizations, such as the US Justice Department, those tied to national security, and local law enforcement don’t have to comply with the legislation of the EPPA. They can implement polygraph policies into their pre-employment screening and employee management processes as they see fit.

Private investigation firms work closely with polygraph testing companies. They use lie detector tests in a variety of casework to assist law enforcement and private detective cases involving criminal and non-criminal investigations.


Fraud, Theft, and Sexual Harassment Cases

The private sector may implement polygraph policies in their organizations to help them discover instances of fraud, theft, and sexual harassment. The EPPA allows companies to implement polygraph policies in these cases to help them root out bad actors from their organizations.

For instance, if inventory theft presents an economic risk to the company, the employer can use a polygraph to uncover the thief. While companies cannot use the results of these tests to harass or threaten employees or as the basis for legal action, they’re useful in uncovering suspected criminals in their organization.

The same applies to instances of fraud at financial firms. If an employee is suspected of embezzling funds, the employer can implement a polygraph policy to resolve the matter. Polygraphs are also allowed by the EPPA to assist employers in settling claims of sexual harassment between colleagues in the workplace.


Sexual Offences

Polygraphs are used by the parole board and the Justice Department to monitor sexual offenders, particularly those involved in child sexual exploitation cases. The Lie detector can assist authorities in discovering sexually predatory behavior and prosecuting these individuals in court.

Many court systems in states like New York, California, Florida, and Illinois don’t allow for polygraph results as admissible evidence in cases. However, there are some exceptions, depending on the judge involved in presiding over the case.


How Does the Modern Polygraph Compare to the Original Devices?

The modern polygraph is a far superior device to the original “Keeler Polygraph.” The introduction of computerized systems and software in the 1990s revolutionized the industry. These innovations dramatically improved the accuracy of polygraph results.

Previously, the Keeler polygraph was estimated at 60% to 70% accuracy. However, the technological advancements offered by software and algorithms improved polygraph accuracy to approximately 97%.


Polygraph Science and Artificial Intelligence

Today, artificial intelligence presents a new frontier in polygraph technology. The US Border Patrol uses a system called “AVATAR” to assist them with screening immigrants coming into the United States. Avatar is an AI-based system capable of detecting deception, even in examinees, using countermeasures.

AVATAR helps the US Border Patrol screen suspected terrorists and criminals trying to enter the country. If an examinee presents deceptive behavior in the screening process, the system refers them to a human-based screening process for further investigations.

There’s no telling where AI could lead the polygraph industry in the future. Already, the device is up to 80% accurate at detecting deception, and we’re only in the early stages of its integration into polygraph technology. AI presents an intriguing prospect for the future of polygraph technology, but there is still a way to go in successfully integrating it into private and public-sector applications.


How Do You Arrange a Polygraph Exam?

Suppose you want to arrange a polygraph exam for private use in spousal fidelity cases or establish a company polygraph policy. In that case, you’ll need to speak to a polygraph company offering these services. These organizations work with the private sector in executing polygraph policies and exams.

The polygraph firm must have accreditation by the American Polygraph Association. They’ll appoint an examiner to work with the company and their legal team to establish the parameters of a polygraph policy. The examiner ensures the policy is in line with EPPA legislation, and they’ll assist with preparing employees or polygraph examinees with preparing for the exam.

This article was originally published at All rights reserved and used with permission.

Originally posted 2023-09-15 11:40:07.