The polygraph is the benchmark in deception detection today. However, the early invention and use of the device had nothing to do with uncovering lies. Dr. James MacKenzie was one of the early pioneers of polygraph technology, being the first scientist to coin the term “polygraph” for his invention.

Dr. James MacKenzie was a celebrated cardiologist and highly regarded in his field. This post examines his life, his work, and the contributions he made to polygraph science.


Who Was Dr. James MacKenzie?

James MacKenzie was born on April 12, 1953, in Scone near Perth, Scotland, to Robert and Jean Campbell MacKenzie. He attended Perth Academy until age 15, leaving school to take an apprenticeship at a chemist in Perth.

At age 21, MacKenzie entered the medical program at The University of Edinburgh, graduating in 1878. He started his career in medicine at Edinburgh’s Royal Infirmary before starting a General Practice in Burnley.

During his time in practice between 1879 and 1902, MacKenzie developed an interest in heart failure. In 1892, he published “The Study of the Pulse, Arterial, Venous and Hepatic and the Movements of the Heart” and introduced his polygraph device for studying cardiological rhythms.

At age 54, MacKenzie moved from Burnley to London, establishing himself as a successful consulting physician. His work included demonstrating the efficacy of the drug “Digitalis” in arrhythmia treatment and the energetics of the heart.

His polygraph instrument enabled him to distinguish between normal and dangerous pulse irregularities. He published his book, “Diseases of the Heart” in 1908, summarizing his work on diagnosing the human pulse and the impact of cardiovascular disease.

During WWI, MacKenzie consulted with the Military Heart Hospital, an institution of which he was a founding member. King George V knighted him in 1915 for his contributions to the field of cardiology and his work with the Military Heart Hospital.

MacKenzie left London, moving to St Andrews, where he continued his work at St Andrews University, founding the “James Mackenzie Institute for Clinical Research.” MacKenzie was described as a tall, well-built, bearded man nicknamed “The big brown bear.”

He had a thick Scottish accent and didn’t appreciate talking with fools. He was always courteous and polite but sometimes dogmatic in his thinking. MacKenzie was conservative with his approach to drug therapy and emphasized bedside inspections, auscultation of the heart, and detailed examination of neck veins.

MacKenzie would observe his patients for a full week before prescribing any medication. When implementing drug therapies, he would introduce one compound at a time and note the effects produced.


How Did Dr. James MacKenzie’s Polygraph Device Work?

Dr. James MacKenzie was the first person to develop a polygraph machine. However, the doctor didn’t have any interest in using it for practices involving deception detection. His classic publication, “The Study of the Pulse,” released in 1902, described his invention, the “Polygraph.”

His polygraph allowed him to correlate venous and arterial pulses with the heartbeat itself. The device recorded information from both sources simultaneously and accurately, using a similar mechanism to what John A. Larson would use in his Lie Detector device a decade or more later.

His polygraph was a modification of the Riva-Rocci “sphygmograph,” which was capable of recording pulse rates on charts. His innovation was instrumental in his cardiology work, allowing MacKenzie to treat and save many lives during his medical career.

MacKenzie used the polygraph to evaluate the patient’s heart condition by measuring their AV interval. In 1890, MacKenzie used the Polygraph to discover premature ventricular contractions, allowing him to distinguish between harmless and dangerous pulse irregularities, known as arrhythmias.

While he didn’t realize his device would have applications in deception detection at the time, it wasn’t long before the science made it into this field.


Did Dr. James MacKenzie Beat Marston & Larson to Inventing the Polygraph?

Dr. James MacKenzie developed his polygraph instrument in the late 1800s, writing about it in a paper published in 1902. William Marston created his “Systolic Blood Pressure Test” and the mechanism to measure it in the early 1900s.

The first official “lie detector” by today’s polygraph standards was invented by the American John A. Larson. Larson was a UCLKA and Stanford student, moonlighting with the Berkeley Police Department in the 1910s. Larson relied on Marston’s work as the foundation of his invention, not MacKenzie’s device.

That said, there are striking similarities between MacKenzie’s device and Larsons. For instance, they both recorded the patient/examinees’ vital responses on smoke paper. However, Larson only perfected his polygraph in the late 1910s. Therefore we can consider MacKenzie’s device as the first official polygraph.

MacKenzie even named his invention the “Polygraph,” with Larson hesitating to call his device a “lie detector,” not a polygraph. The media eventually nicknamed Larson’s polygraph “The Sphyggy” because they grew tired of calling it a “Sphygmomanometer” and frequently messed up the word’s pronunciation.

So, while MacKenzie beat Larson to creating a device that could measure cardiovascular activity, it was Larson that built the first purpose-driven polygraph intended for use in deception detection and law enforcement applications.


How Does the Cardiovascular System Affect Polygraph Results

The cardiovascular system plays a central role in polygraph science. The heart and lungs make up the cardiovascular system, and the activity produced is governed by the central nervous system (CNS) and autonomic nervous system (ANS).

The ANS comprises the parasympathetic nervous system (PSNS) and the sympathetic nervous system (SNS). The SNS is responsible for launching the “fight-or-flight” (FoF) response that examiners use to detect deception during the polygraph test.

We cannot control the FoF and how the brain signals the ANS to activate it. That’s why the polygraph is such an effective instrument for detecting deceptive behavior. When we’re in a stressful situation, the subconscious mind signals the brain to prepare the SNS and prime the FoF. When we experience a stimulus, such as a question forcing us to lie, the SNS launches the FoF.

Larson and Keeler’s “Sphyggy” and “Emotograph” rely on the machine’s interpretation of cardiovascular activity to understand if the examinee is undergoing a “fight-or-flight” (FoF) response to their questions.

The modern polygraph operates in a similar manner, using software to interpret these physiological signs. The modern polygraph relies on the following three vital signs when assessing the FoF response to the examiner’s questions.


Blood Pressure

The examiner attaches a standard, inflatable blood pressure cuff to the examinee’s arm before they start the exam. The cuff measures the examinee’s blood pressure results during questioning. The launch of the FoF response creates a notable elevation in blood pressure which the examiner sees on the chart layout on their laptop screen when viewing the software.

Pulse Rate

The examiner attaches a sensor to the examinee’s fingertip before they start the polygraph exam. The sensor monitors the examines heart rate during the process. If the examiner asks a question that activates the FoF response in the examinee, the sensor will pick up an increase in their pulse rate.

Respiration Rate

The examiner attaches a corrugated rubber tube to the examinee’s chest before they start the polygraph exam. The tube measures the examinee’s respiration rate under questioning. If a question activates the FoF response, the tube will detect an increase in respiration rate in the examinee.


The polygraph instrumentation is incredibly sensitive and picks up any variations in the change of these vital signs and their function in the body. Some examinees believe they can use “countermeasures” to suppress these responses.

For instance, controlling their breathing, thinking nasty thoughts, biting their tongue, or curling their toes may interfere with the FoF response and the elevation in these cardiovascular markers. However, that is not the case.

While these countermeasures might slightly interfere with the FoF, the examiner will notice these attempts on their software readout. They’ll ask the examinee if they’re using any countermeasures, and if they are, it results in a failed polygraph exam.

Suppressing the FoF requires a person to have control over their ANS and SNS, and that simply isn’t possible. Even the use of anti-anxiety drugs, like Xanax, won’t be enough to stop the activation of the SNS and FoF.


Dr. MacKenzie’s Polygraph Vs. The Keeler Polygraph

John A. Larson is considered “The Father of the Polygraph” alongside MacKenzie, who bears the same moniker, as does Leonard Keeler. Larson progressed Marston’s work, leading to him developing the “Sphyggy.” However, it’s not known if he knew of MacKenzie and his polygraph design at the time of its invention.

Communication services were not great in the early 1900s, before the use of fax machines and email. So, it’s doubtful that Larson had any idea of MacKenzie’s work while developing his lie detector device.

However, upon its launch, Larson’s lie detector caught the attention of another man, Leonard Keeler. Keeler was another UCLA student moonlighting in the Berkeley Police Department and became friends with Larson. The duo met after Larson developed his prototype, and Keeler went on to redesign it, bringing several innovations to Larson’s original model.

The Keeler polygraph did away with the need for smoke paper and shellacking. Instead, it relied on ink pens to draw the changes in physiological responses on chart paper. This innovation made the machine’s setup easier and faster while allowing for easier storage of the test results.

The Keeler polygraph also incorporated heart rate, blood pressure, and skin electrical activity analysis into one device. As a result, the accuracy of Keeler’s polygraph was better than Larson’s original design. MacKenzie’s Polygraph was not purpose-built for lie detection.

Instead, it was solely intended for monitoring a patient’s heart condition by measuring their AV interval. It was a medical device designed for cardiovascular diagnosis, not deception detection. Therefore, we can’t really compare McKensie’s and Keeler’s designs because they have different applications.

However, we don’t know how effective the Keeler polygraph would have been in medical applications outside of deception detection. Could MacKenzie’s work have benefited from Keeler’s innovations? It’s hard to tell.


Keeler’s Life and Similarities Between Dr. James MacKenzie

Leonard Keeler built three versions of his polygraph while he was alive. The man suffered a stroke when he was 45 years old in 1949. Keeler’s wife left him in the 1940s for another man, and the stress caused by the incident led him down a path of depression and heavy alcohol and tobacco use.

Like MacKenzie, Keeler died from a cardiovascular event. It’s ironic how both men who had the biggest influence on the development of the modern polygraph died of heart-related diseases and illnesses. Considering the parallels between the men’s work and their devices, it’s almost uncanny how they could share similar fates.

One wonders if Keeler would have experienced a different life course if he had met MacKenzie. Would he have learned anything new from MacKenzie’s work? Would MacKenzie’s medical specialty have prevented him from leading a life of declining health, resulting in a stroke?

These are questions we will never have answers to. However, both men had a huge impact on polygraphy, and without them, polygraph science might not have progressed to where it is today.


Dr. James MacKenzie – Death and Legacy

While Dr. MacKenzie dedicated his life to treating people with heart disease, he would ironically die of ischemic heart disease. The doctor experienced a heart attack in 1901, recording his atrial fibrillation that accompanied the episode.

Mackenzie experienced episodes of “angina pectoris” in 1907, mentioning his condition to Sir Thomas Lewis. In 1908 he experienced severe cardiac pain due to myocardial infarction (heart attack). His angina continued during 1908, progressively worsening until January 1925, when he died at 4 am on January 26, after a severe and prolonged angina attack.

MacKenzie requested John Parkinson to perform an autopsy on his body after his death. The results showed coronary artery disease and physical evidence of recent and prior myocardial infarction. The British Heart Journal published a description of the case in 1939.

Today, the Tayside Medical History Museum hosts two early versions of his polygraph device and a bronze bust commemorating his contribution to medical science and cardiology.


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