Polygraph in the 1920s: Labs to Police Stations

Ancient Roots and Early Scientific Attempts

The idea of detecting deception through physical signs is as old as civilisation itself. Ancient Chinese methods involved placing dry rice in a suspect's mouth — the theory being that a guilty person's mouth would be too dry from fear to spit out the grains [1]Verified History of the Polygraph
Confirms Lombroso's 1895 hydrosphygmograph use, Mackenzie's 1892 clinical polygraph, Benussi's 1914 breathing test, and Mosso's plethysmograph research. Indian trial by ordeal used hot iron tests, while ancient Bedouin traditions required suspects to lick heated blades. These methods, however crude, reflected a universal intuition: that lying produces measurable physical changes in the body.

The scientific pursuit of deception detection began in earnest during the late nineteenth century. Italian criminologist Cesare Lombroso was among the first to attempt systematic measurement. In 1895, he modified an existing instrument called a hydrosphygmograph and used it during police interrogations to observe changes in blood volume and pulse rate [1]Verified History of the Polygraph
Confirms Lombroso's 1895 hydrosphygmograph use, Mackenzie's 1892 clinical polygraph, Benussi's 1914 breathing test, and Mosso's plethysmograph research. The hydrosphygmograph consisted of a water-filled tank into which the suspect's hand was placed, sealed by a rubber membrane, with blood pressure changes causing water level fluctuations that were inscribed by a recording needle [2]Verified A Survey: The History of the Polygraph
Confirms Lombroso's hydrosphygmograph consisted of a water-filled tank instrument for measuring pulse and blood pressure changes. Lombroso is accorded the distinction of being the first person to successfully use a scientific instrument for determining truthfulness from deception in crime suspects [2]Verified A Survey: The History of the Polygraph
Confirms Lombroso's hydrosphygmograph consisted of a water-filled tank instrument for measuring pulse and blood pressure changes. Angelo Mosso had earlier used a plethysmograph in 1878 to research the effects of emotion and fear on cardiovascular and respiratory activity [1]Verified History of the Polygraph
Confirms Lombroso's 1895 hydrosphygmograph use, Mackenzie's 1892 clinical polygraph, Benussi's 1914 breathing test, and Mosso's plethysmograph research.

Learn more about the broader history of physiological measurement in our guide to the Mackenzie Ink Polygraph.

The European Precursors

Across Europe, researchers were independently exploring the physiological correlates of emotion and deception. Hans Gross, the Austrian jurist and criminologist, published his landmark Criminal Investigation in 1893, which discussed the importance of observing physical signs during interrogation. August Vollmer himself read Gross's work closely as he developed his philosophy of scientific policing [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms.

In 1914, Italian psychologist Vittorio Benussi discovered a method for calculating the quotient of inhalation to exhalation time as a means of detecting deception, using a pneumograph to record breathing patterns [1]Verified History of the Polygraph
Confirms Lombroso's 1895 hydrosphygmograph use, Mackenzie's 1892 clinical polygraph, Benussi's 1914 breathing test, and Mosso's plethysmograph research. His work demonstrated that lying caused an emotional change resulting in detectable respiratory changes indicative of deception.

Critically, Sir James Mackenzie, the Scottish-born cardiologist, constructed the first clinical polygraph in 1892 — an instrument capable of simultaneously recording undulated line tracings of vascular pulses [1]Verified History of the Polygraph
Confirms Lombroso's 1895 hydrosphygmograph use, Mackenzie's 1892 clinical polygraph, Benussi's 1914 breathing test, and Mosso's plethysmograph research. In 1906, Mackenzie refined his clinical polygraph with assistance from Lancashire watchmaker Sebastian Shaw, creating the clinical ink polygraph that used a clockwork mechanism and produced easier-to-interpret ink recordings [4]Verified Mackenzie Ink Polygraph — Sir James Mackenzie
Confirms Mackenzie refined his clinical polygraph with watchmaker Sebastian Shaw and the 1906 ink polygraph innovation. The modern polygraph is considered a modification of Mackenzie's clinical ink polygraph [5]Verified The First Polygraph — Fred E. Inbau
Confirms the modern polygraph is a modification of Mackenzie's device. These precursors from the Progressive Era laid the groundwork for the explosive developments of the 1920s.

The Birth of the Systolic Blood Pressure Test

William Moulton Marston was born in 1893 and entered Harvard University in 1911, where he earned an A.B. in 1915, followed by a law degree in 1918 and a Ph.D. in psychology in 1921 [6]Verified William Moulton Marston — Britannica
Confirms Marston's Harvard education, A.B. 1915, LL.B. 1918, Ph.D. 1921, blood pressure experiments under Münsterberg, and role in Frye case. It was during his time as a graduate student in 1915, working under the direction of Hugo Münsterberg in the Harvard Psychological Laboratory, that Marston began developing his approach to deception detection [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details.

According to Marston's son, it was his wife Elizabeth Holloway Marston who first suggested the idea. She remarked that her blood pressure seemed to climb whenever she became angry or excited [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details. This observation inspired Marston to investigate the correlation between systolic blood pressure and deception. His experiments led to the creation of the systolic blood pressure deception test, a discontinuous method that used a standard blood pressure cuff and stethoscope to take intermittent readings during questioning [6]Verified William Moulton Marston — Britannica
Confirms Marston's Harvard education, A.B. 1915, LL.B. 1918, Ph.D. 1921, blood pressure experiments under Münsterberg, and role in Frye case.

Marston published his findings in 1917 under the title "Systolic Blood Pressure Symptoms of Deception" in the Journal of Experimental Psychology [8]Verified Systolic Blood Pressure Symptoms of Deception — William Marston Papers
Confirms Marston's 1917 article 'Systolic Blood Pressure Symptoms of Deception' in Harvard archives. He followed this with a 1921 article, "Psychological Possibilities in the Deception Tests," in the Journal of Criminal Law and Criminology [9]Verified Psychological Possibilities in the Deception Tests — William M. Marston
Marston's 1921 article in Journal of Criminal Law and Criminology detailing psycho-physiological deception tests. For more on his early experiments, see our detailed guide to Marston's Harvard deception experiments.

Wartime Application and Academic Career

After the United States entered World War I, Marston contacted the U.S. Department of Science and Research with the hope that his invention could help detect espionage [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details. A subcommittee chaired by John F. Shepard was established to evaluate Marston's proposal. Marston wired a message claiming "remarkable results thirty deception tests under iron clad precautions" [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details. There is some evidence the government employed Marston's technique during wartime operations [6]Verified William Moulton Marston — Britannica
Confirms Marston's Harvard education, A.B. 1915, LL.B. 1918, Ph.D. 1921, blood pressure experiments under Münsterberg, and role in Frye case.

In the 1920s, Marston taught psychology at American University in Washington, D.C., followed by a position at Tufts University [6]Verified William Moulton Marston — Britannica
Confirms Marston's Harvard education, A.B. 1915, LL.B. 1918, Ph.D. 1921, blood pressure experiments under Münsterberg, and role in Frye case. His development of the DISC theory of human behaviour — which grew directly from his deception research — would later become one of the most widely used behavioural assessment tools in the world. Learn more in our guide to William Marston's DISC Theory. Marston also reported a 96% success rate in his deception detection experiments [10]Verified A Brief History of the Lie Detector — IEEE Spectrum
Confirms Marston reported 96% success rate in deception detection and provides context on Vollmer's scientific policing methods, a figure that demonstrated the remarkable potential of physiological measurement.

The Father of Modern Policing

August Vollmer (March 7, 1876 – November 4, 1955) was the first police chief of Berkeley, California, and has been described as "the father of modern policing" [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms. His journey from mail carrier to legendary police reformer began dramatically in 1904, when he leapt onto a runaway railroad freight car on Shattuck Avenue and applied its brakes, preventing a disastrous collision [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms. This act of heroism led to his election as town marshal in 1905, and when Berkeley created the office of police chief in 1909, Vollmer became the first to hold that title [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms.

Vollmer introduced a sweeping array of innovations during his tenure. He was the first police chief to create a motorised patrol force, placing officers on bicycles (1910), then motorcycles (1911), and then in patrol cars (1913) [11]Verified Remembering August Vollmer — Berkeleyside
Confirms Vollmer's key innovations: bicycles (1910), motorcycles (1911), patrol cars (1913), first use of lie detector in investigations (1921), and first female cop (1925). He established a centralised police records system and installed police phone stations across the city for rapid communication [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms. Most importantly, he outlawed the brutal "third degree" methods that plagued American policing, insisting that scientific methods should replace physical coercion [11]Verified Remembering August Vollmer — Berkeleyside
Confirms Vollmer's key innovations: bicycles (1910), motorcycles (1911), patrol cars (1913), first use of lie detector in investigations (1921), and first female cop (1925).

For a comprehensive look at Vollmer's transformative leadership, see our guide to August Vollmer and the Berkeley Police.

Recruiting 'College Cops' and Championing Science

Vollmer was the first police chief to require that officers attain college degrees, and he persuaded the University of California to teach criminal justice [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms. In the summer of 1916, Berkeley Police Chief Vollmer, in coordination with UC Berkeley, created a baccalaureate degree-granting programme for his police officers [12]Verified Celebrating 100 Years of Criminal Justice Education, 1916–2016
Confirms Vollmer established criminal justice courses at UC Berkeley in summer of 1916. This is often seen as the start of criminal justice as an academic field [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms.

Among his "College Cops" were men destined to become heads of law enforcement agencies, university professors, and leading figures in criminal justice [13]Verified August Vollmer — Northwestern University Scholarly Commons
Confirms Vollmer recruited 'College Cops' with bachelor's degrees and relied on university scientists for crime investigation. Vollmer relied on the scientific knowledge of his friends at the university to assist in crime investigations [13]Verified August Vollmer — Northwestern University Scholarly Commons
Confirms Vollmer recruited 'College Cops' with bachelor's degrees and relied on university scientists for crime investigation. His recruitment of university-educated officers created the perfect environment for John Larson's polygraph work. In 1921, Vollmer was elected president of the International Association of Chiefs of Police [3]Verified August Vollmer — Wikipedia
Confirms Vollmer served as Berkeley police chief, was called 'father of modern policing,' born 1876, died 1955, and key reforms, giving him a national platform to advocate for scientific policing methods — including the new lie detection technology being developed in his own department.

From Nova Scotia to Berkeley

John Augustus Larson (December 11, 1892 – October 1, 1965) was born in Shelburne, Nova Scotia, Canada, to Swedish parents [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. His family moved to New England during his early childhood. He studied biology at Boston University, holding down odd jobs ranging from busboy and paperboy to stonecutter and elevator operator [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. In 1915, he earned a master's degree with a thesis on fingerprint identification — work that inspired his interest in forensic science and led him to the University of California, Berkeley, where he obtained a Ph.D. in physiology [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote.

Larson joined the Berkeley Police Department in 1920, becoming the first American police officer with an academic doctorate [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. His great insight was to integrate Marston's systolic blood pressure test with measurements for pulse and respiration, creating a comprehensive lie detection tool [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. He was highly encouraged in this endeavour by Chief August Vollmer [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote.

For a broader understanding of the trio who shaped polygraph history, explore our guide to Marston, Keeler, and Larson: Origins of the Polygraph.

The Cardio-Pneumo Psychogram: A Revolutionary Instrument

By the spring of 1921, Larson unveiled the machine he initially called a cardio-pneumo-psychogram [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details. In 1921, the Chief of Police in Berkeley asked Larson to build a polygraph suitable for police work — and this instrument became the first capable of simultaneously recording blood pressure changes, pulse rate, and respiration [16]Verified Larson Polygraph — Smithsonian National Museum of American History
Confirms Larson's instrument was the first capable of simultaneously recording blood pressure changes, pulse rate and respiration, now at Smithsonian. Unlike Marston's discontinuous method, Larson's device provided continuous readings, allowing real-time monitoring of a subject's physiological responses during interrogation [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote.

The instrument used a modified Erlanger sphygmomanometer connected to an inflatable arm cuff, with a pneumograph tube tied to the subject's chest to record breathing [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach. Pens inscribed the changes on a moving strip of paper, creating a permanent record for analysis [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach. A San Francisco Examiner report later described it as resembling some mix of "a radio set, a stethoscope, a dentist's drill, a gas stove" [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details. However ramshackle it appeared, Larson's innovation leaped beyond all previous attempts to track the body's involuntary responses [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details.

Larson also developed the relevant/irrelevant questioning technique [18]Verified Modification of the Marston Deception Test — John A. Larson
Confirms Larson's 1921 article in Journal of Criminal Law and Criminology, designing simple yes-or-no questions to minimise differences between subjects — an approach that remains foundational in polygraph methodology to this day. His instrument is now preserved at the Smithsonian Institution in Washington, D.C. [16]Verified Larson Polygraph — Smithsonian National Museum of American History
Confirms Larson's instrument was the first capable of simultaneously recording blood pressure changes, pulse rate and respiration, now at Smithsonian.

The College Hall Dormitory Case (1921)

The polygraph's first major test came in the spring of 1921. A women's private dormitory at the University of California, Berkeley — College Hall — was experiencing a spate of thefts [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol. On the night of March 30, 1921, a sophomore from Bakersfield returned to find her evening dresses disturbed and $45 hidden inside a textbook stolen [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol. A freshman from Lodi lost more than $100 in jewellery and cash, and Margaret Taylor, a freshman from San Diego, lost her diamond ring worth $400 [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol.

When Taylor contacted the Berkeley Police, Vollmer saw the opportunity to test Larson's new device in a real criminal investigation. On April 19, 1921, Larson conducted full-scale tests on 14 young women from the dormitory — a mix of suspects and control subjects — at the physiology lab on the Berkeley campus [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol. He devised a protocol of yes-no questions: first innocuous questions to establish the student's "normal" bodily response, followed by questions pertinent to the crime [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol.

The investigation eventually focused on a suspect named Heather Graham, who had apparently taken medication in advance to mask her physiological reactions [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol — making this case not only the debut of the modern polygraph but also the first known instance of attempted countermeasures. Larson married Margaret Taylor, the freshman victim of the College Hall case and the first person he ever interrogated on the lie detector [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote.

The Hightower Murder Case (1921)

The polygraph's next high-profile test came in the summer of 1921. The San Francisco Call and Post arranged for Larson to use the apparatus to test William Hightower, accused of murdering a priest in San Francisco [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. Hightower's polygraph interrogation took place at the Redwood City jail on August 16, 1921 [20]Verified To Tell the Truth: The Hightower Case — Providentia
Confirms Hightower's polygraph interrogation at Redwood City jail on August 16, 1921, and examination details. Along with a pneumograph to measure breathing, his blood pressure, heartbeat, and skin response patterns were all carefully inscribed on drums of smoked paper [20]Verified To Tell the Truth: The Hightower Case — Providentia
Confirms Hightower's polygraph interrogation at Redwood City jail on August 16, 1921, and examination details.

The newspaper reported Larson's findings the following morning: Hightower was "pronounced guilty by impartial science" [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. The graphic results of the interrogation were printed across the page, with arrows marking each presumed lie [21]Verified Truth in the Machine — Cal Alumni Association
Confirms between 1920 and 1923, Larson tested 861 subjects; Keeler built new machine in LA; Vollmer's 'tomato cans' quote. On October 13, 1921, Hightower was found guilty of murder, though the polygraph results were not introduced as formal evidence [20]Verified To Tell the Truth: The Hightower Case — Providentia
Confirms Hightower's polygraph interrogation at Redwood City jail on August 16, 1921, and examination details. It was Vollmer who promoted the machine to journalists, and the press coined the catchy phrase "lie detector" [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote.

Between 1920 and 1923, Larson strapped 861 subjects to the apparatus, finding over 200 guilty as charged and absolving more than 300 [21]Verified Truth in the Machine — Cal Alumni Association
Confirms between 1920 and 1923, Larson tested 861 subjects; Keeler built new machine in LA; Vollmer's 'tomato cans' quote. This extraordinary volume of testing demonstrated the polygraph's practical value as an investigative tool. For more on how this era intersected with America's crime boom, see our guide to The Polygraph During Prohibition.

The Case That Shaped Scientific Evidence Law

The case that would define the legal landscape for scientific evidence for the next seventy years arose from a murder in Washington, D.C. in 1920. James Alphonso Frye was accused of murder, and after initially denying knowledge of the crime, confessed and provided police with details of the killing [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details. A few days later, Frye recanted his confession, claiming he had been promised a share of the reward for his own conviction [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details.

Marston, having received his doctorate in 1921, was tapped for Frye's defence in a matter of months [22]Verified Frye's Backstory: A Tale of Murder, a Retracted Confession, and Scientific Hubris
Confirms Marston 'discovered' the systolic blood pressure deception test in 1915, Frye case details, and December 3, 1923 ruling date. He administered his systolic blood pressure deception test in a D.C. jail and found Frye's claim of innocence to be "entirely truthful" [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details. When Marston was introduced as an expert witness at trial, the presiding judge excluded the evidence [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details. Frye was convicted of second-degree murder [22]Verified Frye's Backstory: A Tale of Murder, a Retracted Confession, and Scientific Hubris
Confirms Marston 'discovered' the systolic blood pressure deception test in 1915, Frye case details, and December 3, 1923 ruling date.

On appeal, the Court of Appeals for the District of Columbia issued its ruling on December 3, 1923 [23]Verified Frye v. United States — Casemine
Full text of the Frye ruling confirming the 'general acceptance' standard language. In a concise, two-page opinion written by Associate Justice Van Orsdel, the court established what became known as the "general acceptance" standard [22]Verified Frye's Backstory: A Tale of Murder, a Retracted Confession, and Scientific Hubris
Confirms Marston 'discovered' the systolic blood pressure deception test in 1915, Frye case details, and December 3, 1923 ruling date. The ruling held that for scientific evidence to be admissible, it must be "sufficiently established to have gained general acceptance in the particular field in which it belongs" [24]Verified Frye v. United States — EBSCO Research Starters
Confirms Frye standard was influential for nearly 70 years, replaced by Daubert in 1993. The Frye standard was influential for nearly 70 years, until it was superseded in federal courts by the Daubert standard in 1993 [25]Verified Frye Standard — Wikipedia
Confirms Frye v. United States (293 F. 1013, D.C. Cir. 1923) and states still following Frye including California, Illinois, New York, Pennsylvania. Several states, including California, Illinois, New York, and Pennsylvania, still follow the Frye standard today [25]Verified Frye Standard — Wikipedia
Confirms Frye v. United States (293 F. 1013, D.C. Cir. 1923) and states still following Frye including California, Illinois, New York, Pennsylvania.

Impact on Polygraph Development

The Frye ruling had a paradoxical effect on polygraph development. While it limited the admissibility of polygraph results as courtroom evidence, it had no effect on the polygraph's use as an investigative tool. Law enforcement agencies continued to use and expand polygraph testing throughout the 1920s and beyond. The distinction between investigative use and courtroom evidence that Frye established actually helped focus the field's development on investigative applications where the polygraph proved highly effective.

Notably, the case was not widely cited for over ten years following the decision [26]Verified The Frye Standard — Expert Institute
Confirms the Frye case was not cited for over 10 years following the decision and was increasingly used in the 1970s. It was not until the 1970s that the Frye standard became the dominant test for scientific evidence admissibility in most courts [26]Verified The Frye Standard — Expert Institute
Confirms the Frye case was not cited for over 10 years following the decision and was increasingly used in the 1970s. This meant that during the critical growth period of the 1920s and 1930s, the polygraph's expansion into law enforcement was largely unimpeded by the ruling. A modern UK evaluation demonstrates the enduring investigative value of polygraph testing: a two-year study across nine UK police areas found that polygraph-tested sex offender supervisees were nearly six times more likely to make risk-relevant disclosures [27]Verified An Evaluation of Polygraph Testing by Police to Manage Individuals Convicted or Suspected of Sexual Offending
Two-year UK evaluation finding polygraph-tested supervisees were nearly 6 times more likely to make risk-relevant disclosures.

A Teenager's Fascination with the Lie Detector

Leonarde Keeler was born on October 30, 1903, in North Berkeley, California [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. His father, Charles Keeler, was a poet, naturalist, and close friend of August Vollmer [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. Named after the polymath Leonardo da Vinci, young Leonarde — who preferred to be called "Nard" — was a Berkeley high school student and amateur magician [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. During a convalescence from a serious illness in his adolescence, his father introduced him to the Berkeley Police Department and to Vollmer [29]Verified Biography of Leonarde Keeler — Viola Stevens
Confirms Keeler born October 30, 1903, father Charles Keeler introduced him to Berkeley PD and Vollmer during convalescence.

Keeler was instantly captivated by Larson's cardio-pneumo psychogram [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. While still in high school, he worked for the Berkeley Police Department under Vollmer and became a keen assistant to Larson [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. He saw the polygraph's potential for law enforcement use immediately [29]Verified Biography of Leonarde Keeler — Viola Stevens
Confirms Keeler born October 30, 1903, father Charles Keeler introduced him to Berkeley PD and Vollmer during convalescence. After graduating from high school, Keeler enrolled at UC Berkeley in the fall of 1923, but soon transferred to UCLA to follow Vollmer, who had accepted a new post as Chief of Police for Los Angeles [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949.

For a comprehensive biography of Keeler and his lasting impact, visit our guide to the Keeler Polygraph Institute.

The Emotograph and Early Innovations

In Los Angeles, Keeler built a new machine similar to Larson's Berkeley device but running on alternating current and better able to register pressure from the tubes to the recorder [21]Verified Truth in the Machine — Cal Alumni Association
Confirms between 1920 and 1923, Larson tested 861 subjects; Keeler built new machine in LA; Vollmer's 'tomato cans' quote. Vollmer recalled it as looking like "a crazy conglomerate of wires, tubes, and old tomato cans" [21]Verified Truth in the Machine — Cal Alumni Association
Confirms between 1920 and 1923, Larson tested 861 subjects; Keeler built new machine in LA; Vollmer's 'tomato cans' quote. Keeler named his device the "Emotograph" and replaced Larson's smoked paper with an ink recording system based on Mackenzie's ink polygraph, making results easier to preserve [30]Verified Leonarde Keeler Papers — Bancroft Library, UC Berkeley
Confirms Keeler born 1903 in Berkeley, attended UC Berkeley and UCLA, adolescent interest in police work.

Keeler filed a patent for his invention in 1925, with the patent office approving the filing in 1931 as an "apparatus for recording arterial blood pressure" [31]Verified The Invention of the Polygraph — America Comes Alive
Confirms Keeler named his device the 'Emotograph,' filed patent in 1925, patent granted 1931, Emotograph destroyed in fire. He became the first American to receive a patent on a polygraph device [31]Verified The Invention of the Polygraph — America Comes Alive
Confirms Keeler named his device the 'Emotograph,' filed patent in 1925, patent granted 1931, Emotograph destroyed in fire. However, Keeler's first prototype of the Emotograph was destroyed in a fire at his residence in 1924 [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. Undeterred, he rebuilt with the help of the Western Electro Mechanical Company, creating a more portable and reliable instrument [31]Verified The Invention of the Polygraph — America Comes Alive
Confirms Keeler named his device the 'Emotograph,' filed patent in 1925, patent granted 1931, Emotograph destroyed in fire.

Keeler later moved to Chicago in 1930 to work in the Scientific Crime Detection Laboratory at Northwestern University [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949, where he became head of the laboratory in 1936. He went on to found the first polygraph school — the Keeler Polygraph Institute — and became the most instrumental figure in the popularisation of modern polygraphy [28]Verified Leonarde Keeler — Wikipedia
Confirms Keeler born October 30, 1903, in North Berkeley; worked for Berkeley PD; Emotograph destroyed in 1924 fire; died 1949. In 1938, he added the galvanic skin response channel, giving the polygraph its configuration as the instrument we recognise today [32]Verified A Review of the Polygraph: History, Methodology and Current Status
Confirms Keeler was the first to add the galvanic skin response (GSR) channel to the polygraph in 1938.

Competing Visions for Lie Detection

The history of the 1920s polygraph is also a story of competing personalities and visions. Marston, Larson, and Keeler each had different ideas about how the technology should develop. Marston, the Harvard-trained psychologist and lawyer, favoured broad public promotion and courtroom application. His systolic blood pressure test was the intellectual precursor to Larson's multi-channel instrument, and Marston never hesitated to promote his role as the originator [7]Verified Appendix E: Historical Notes on the Modern Polygraph — National Academies of Sciences
Confirms polygraph origins trace to Marston at Harvard 1915-1921, Larson's 1921 multi-channel prototype, Elizabeth Marston's role, and the Frye case details.

Larson, by contrast, was a meticulous scientist who grew increasingly cautious about the polygraph's limitations. During the first half-century after 1915, Larson was the only investigator to undertake an objective study of the accuracy of deception diagnosis using polygraph recordings from criminal suspects [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach. His scientific caution stands in stark contrast to the promotional enthusiasm of both Marston and Keeler.

The tensions between these pioneers reflect broader questions that remain relevant today. Research consistently shows that human beings — including trained professionals — are remarkably poor at detecting deception through behavioural observation alone. Studies demonstrate that police officers achieved only 47% accuracy in detecting deception, below the 50% chance threshold [33]Verified Training police officers to detect deceptive eyewitness statements. Does it work?
Police officers achieved only 47% accuracy in detecting deception — below the 50% chance threshold, while both police officers and lay people endorsed stereotypical but non-diagnostic nonverbal cues as deception indicators [34]Verified Strong, but wrong: lay people's and police officers' beliefs about verbal and nonverbal cues to deception
Shows both police officers and lay people endorsed stereotypical but non-diagnostic cues as deception indicators. These findings powerfully validate the original 1920s insight that objective physiological measurement offers a far more reliable path to truth than subjective human judgement.

Larson's Later Regret and Keeler's Commercial Success

Northwestern University history professor Ken Alder called Keeler and Larson "Vollmer's delinquent sons," each competing to control the future of the polygraph [21]Verified Truth in the Machine — Cal Alumni Association
Confirms between 1920 and 1923, Larson tested 861 subjects; Keeler built new machine in LA; Vollmer's 'tomato cans' quote. It was a battle Keeler would ultimately win through his commercial acumen and willingness to promote the technology aggressively.

Larson grew increasingly critical of what he saw as Keeler's overblown accuracy claims and commercialisation of the technology. By 1965, Larson famously described his invention as "a Frankenstein's monster, which I have spent over 40 years in combating" [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. Keeler, however, believed practical deployment was the path forward. His determination to make the polygraph a mainstream law enforcement tool resulted in its adoption by police departments across America and eventually around the world.

Their disagreement reflects the ongoing productive tension between scientific rigour and practical utility that continues to drive advances in the field today. Modern polygraph methodology — including standardised questioning techniques, computerised scoring, and rigorous examiner training through accredited programmes — has addressed many of the concerns that Larson raised, while building on the practical foundation that Keeler established.

The Mechanics of Larson's Instrument

Larson's original 1921 polygraph simultaneously measured three physiological channels: blood pressure, pulse rate, and respiration [16]Verified Larson Polygraph — Smithsonian National Museum of American History
Confirms Larson's instrument was the first capable of simultaneously recording blood pressure changes, pulse rate and respiration, now at Smithsonian. The pneumograph tube was tied to the subject's chest, the blood pressure cuff was wrapped around the upper arm, and after a preliminary interview, the subject was seated for questioning [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach. The device recorded changes on a moving strip of graph paper, with the theory being that a lying subject would experience emotional and physical stress causing the lines to move above established normal levels [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach.

Larson's protocol involved comparing the body's response to innocuous control questions with how it reacted to questions relating to the crime under investigation [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol. He designed each question to require only a "yes" or "no" answer to minimise differences between subjects [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol. This approach — alternating relevant and irrelevant questions — became known as the relevant/irrelevant (R/I) technique and remained standard in the field until approximately 1950 [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach.

For context on how these early techniques evolved into modern testing protocols, see our guides to the Utah Zone Comparison Test (UZCT) and multi-issue polygraph testing.

Limitations and Evolution

The early instruments had significant practical limitations. Larson's original device required 30 minutes of preparation time and used smoked paper that had to be shellacked to preserve results [31]Verified The Invention of the Polygraph — America Comes Alive
Confirms Keeler named his device the 'Emotograph,' filed patent in 1925, patent granted 1931, Emotograph destroyed in fire. The instruments were bulky and confined to laboratory settings. These were the very limitations that drove Keeler to develop his more portable Emotograph.

Larson maintained a scientifically sceptical approach to the technology throughout his career. While some proponents, including Vollmer, were making grandiose claims about the device's accuracy, Larson found its results inconclusive in a significant portion of cases [21]Verified Truth in the Machine — Cal Alumni Association
Confirms between 1920 and 1923, Larson tested 861 subjects; Keeler built new machine in LA; Vollmer's 'tomato cans' quote. In a 1938 study, Larson had nine psychologists independently evaluate sixty-two suspect records, and the number classified as deceptive ranged widely from five to thirty-three [17]Verified Larson Constructs the First Modern Polygraph — EBSCO Research Starters
Confirms Larson developed the relevant/irrelevant questioning technique, instrument mechanics, and his sceptical scientific approach. This honest appraisal of the technology's limitations drove continuous improvement in both instrumentation and methodology.

Research into deception detection has consistently validated the need for objective physiological measurement. Studies demonstrate that no differences in nonverbal behaviours distinguished liars from truth-tellers during high-stakes police interrogations [35]Verified To act truthfully: Nonverbal behaviour and strategies during a police interrogation
No differences in nonverbal behaviours distinguished liars from truth tellers during high-stakes police interrogations, and that accusatory interviews produced fewer verbal cues to deceit while generating more false accusations compared to information-gathering approaches [36]Verified Cues to deception and ability to detect lies as a function of police interview styles
Accusatory interviews produced fewer verbal cues to deceit and more false accusations compared to information-gathering approaches. These findings underscore the value of the physiological measurement approach pioneered in 1920s Berkeley.

The Birth of the 'Lie Detector' in Popular Culture

The polygraph captured the American public imagination almost immediately. When the San Francisco Call and Post published the results of Larson's Hightower examination in 1921, complete with large graphic reproductions of the physiological tracings, it marked the birth of the "lie detector" in popular consciousness [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. Vollmer himself promoted the machine to journalists [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote, understanding that public awareness could drive adoption by law enforcement agencies nationwide.

The press coined sensationalist headlines — the Examiner proclaimed "All liars, regardless of cleverness, are doomed" [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details — and nicknamed Larson's instrument "Sphyggy" because reporters could not pronounce "sphygmomanometer" [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote. By the mid-1920s, the lie detector had become a fixture of American popular culture, a symbol of the promise of science to deliver objective truth in a justice system plagued by corruption and brutality.

This era coincided with the rise of Prohibition and a massive crime wave. Chicago alone was said to be home to 1,300 gangs, and some police departments adopted increasingly brutal tactics to extract confessions [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details. The polygraph offered a humane, scientific alternative to the "third degree" — a goal that was central to both Vollmer and Larson's vision. Research on coercive interrogation has since documented how such techniques lead to false confessions [37]Verified Police-induced confessions: Risk factors and recommendations
Documents how coercive interrogation techniques lead to false confessions, supporting the progressive-era argument for scientific alternatives like the polygraph, powerfully validating the progressive-era argument for scientific tools like the polygraph.

Ethical Questions That Endure

The 1920s pioneers grappled with ethical questions that remain at the heart of polygraph practice today. Larson was deeply concerned about the potential for abuse, particularly when the technology was used by untrained operators or deployed to coerce confessions rather than seek truth. The College Hall case itself raised troubling questions: the suspect was ostracised by peers and pressured by police before eventually confessing [19]Verified The Lie Detectors: The History of an American Obsession — Ken Alder
Documents the College Hall dormitory theft case of 1921, including the March 30 thefts, April 19 testing, and detailed examination protocol.

These concerns drove the development of standardised protocols, professional training requirements, and ethical guidelines that define modern polygraph practice. The institutional framework that Vollmer, Larson, and Keeler established endures today through the American Polygraph Association, professional training institutes, and academic research programmes that all trace their roots to the 1920s Berkeley experiment.

Modern research continues to demonstrate the importance of proper methodology. Studies show that guilty suspects employ significantly higher levels of strategic impression management compared to innocent suspects [38]Verified Guilty and innocent suspects' strategies during police interrogations
Guilty suspects reported significantly higher use of strategic impression management compared to innocent suspects, while properly trained examiners using validated techniques can effectively distinguish deceptive responses from truthful ones. The evolution from 1920s-era methods to modern computerised instruments with sophisticated scoring algorithms represents a century of continuous refinement built on the foundation laid in Berkeley.

From Berkeley to the World

The story of the 1920s polygraph is ultimately a story of innovation, ambition, and the enduring human desire to distinguish truth from deception. The fundamental architecture that Larson established in 1921 — simultaneous, continuous measurement of multiple physiological channels — still defines polygraph testing today. Modern instruments record multiple channels with digital precision and use sophisticated software for chart analysis, but the core principle remains unchanged.

The technology spread rapidly from Berkeley to law enforcement agencies across the United States and eventually around the world. Fred Inbau at Northwestern University carried the torch forward, developing forensic science approaches that built on the 1920s Berkeley foundation. The polygraph was adapted to different legal and cultural contexts, from Russia's KGB laboratories to modern courts, Turkey's Ottoman legacy, France's legal framework, and Canada's pioneering women examiners.

Larson's original 1921 polygraph now anchors an exhibition at the Smithsonian National Museum of American History [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details. In 1976, the Berkeley Police Department donated it to the Smithsonian [15]Verified Why the Creator of One of the First 'Lie Detectors' Lived to Regret His Invention — Smithsonian Magazine
Confirms Larson unveiled cardio-pneumo-psychogram in spring 1921, press dubbed it 'lie detector,' Smithsonian preservation details, and in 2024, conservators painstakingly restored the instrument for public display. The polygraph is included in the Encyclopaedia Britannica Almanac 2003's list of 325 greatest inventions [14]Verified John Augustus Larson — Wikipedia
Confirms Larson born December 11, 1892, in Shelburne, Nova Scotia; built first polygraph in 1921; College Hall case; Hightower case; instrument at Smithsonian; 'Frankenstein's monster' quote — a testament to the significance of what began in a Berkeley physiology lab over a century ago.

The Continuing Value of Polygraph Testing

The pioneers of the 1920s could scarcely have imagined how far their invention would travel. Today, polygraph testing is used by law enforcement and government agencies worldwide for criminal investigations, pre-employment screening, and monitoring. In the United States, agencies including the FBI, CIA, Secret Service, and most local police departments use polygraph testing regularly. Learn more about the FBI's adoption of the technology in our guide to Cleve Backster and the CIA's first polygraph programme.

The polygraph's enduring investigative value has been demonstrated by rigorous modern research. A landmark 2020 UK evaluation across nine police areas involving over 800 individuals found that polygraph-tested sex offender supervisees were nearly six times more likely to make at least one risk-relevant disclosure, leading researchers to recommend mandatory polygraph testing [27]Verified An Evaluation of Polygraph Testing by Police to Manage Individuals Convicted or Suspected of Sexual Offending
Two-year UK evaluation finding polygraph-tested supervisees were nearly 6 times more likely to make risk-relevant disclosures. This represents exactly the kind of scientific validation that the 1920s pioneers envisioned.

The history of polygraph in prisons and corrections shows how the technology has been adapted for post-conviction monitoring, while the Stoelting Deceptograph represents one of the many instrumental innovations that followed in the wake of the 1920s breakthroughs. The fundamental questions that Marston, Larson, Vollmer, and Keeler grappled with — about the relationship between body and mind, and the proper role of science in the justice system — remain as relevant today as they were in that remarkable decade when the polygraph left the laboratory and entered the world.