In ancient China, a portion of rice spit from a person’s mouth revealed whether he or she was
lying. Spitting out dry rice indicated the dry mouth of a liar.
In Europe, during the Middle Ages, torture was used as a means of forcing a person to tell the
truth. Ken Adler’s article To Tell the Truth: The Polygraph Exam and The Marketing of
American Enterprise states that the practice of torture was rooted in the theory that “the body’s
agony would oblige the lying mind to croak out its secret.”
Europe’s tolerance for torture declined throughout the eighteenth century. In the early 1700s,
Daniel DeFoe was the first to move away from torture by suggesting that deception could be
evaluated by monitoring the heart rate. Cesare Beccaria, in 1764, wrote of torture, “By this
method, the robust will escape, and the feeble be condemned. These are the inconveniences of
this pretended test of truth.”
In 1895, the Father of Modern Criminology Cesare Lombroso, became the first person to use
science as a method of detecting deception. Lombroso used devices called the plethysmograph
and the sphygmograph. The suspect wore an airtight volumetric glove that was attached to a
rubber membrane. This activated a pen that rolled over the surface of a smoked drum. The speed
of the pen varied with the suspect’s blood flow. Lombroso believed that, when a person tells a
lie, the stress of deception affects his or her heart rate and blood pressure. By observing the
deviations traced by the pen, an investigator would see when and if the suspect was lying.
The next advance came in 1897, when B. Sticker developed a method of measuring the amount
of sweat a suspect produced during interrogation. This was determined by the electrical
conductibility of the suspect’s skin.
The first “polygraph” machine was actually a copy machine invented in 1804. The name, derived
from Greek, means “many writings”. In the very early 1900s, James MacKenzie, an English
doctor, invented what he called the “ink polygraph”. This was used to monitor cardiovascular
responses by measuring pulse and blood pressure.
In 1914, Vittorio Benussi used pneumatic tubing to study an individual’s breathing rates. The
device wrapped around the person’s chest and measured depth and rate of breath. Eugene Levitt,
in his article The Scientific Evaluation of the Lie Detector, noted that Benussi’s discovery
showed that the “ratio of inspiration and expiration was generally greater before truth telling than
that before lying.” This last discovery gave scientists the final piece of their puzzle; blood pressure, pulse rates, sweat production, and breathing rates could all be linked to the act of
The polygraph is almost purely American phenomenon;
no other country makes appreciable use of the technique.
~ Gordon D. Barland
William M. Marston (also known as Charles Marston), a psychologist born and raised in
Massachusetts, invented the true early prototype for the lie detector machine. In 1915, Marston,
with the help of his wife Elizabeth, first demonstrated a lie detection test that used asphygmomanometer (blood pressure cuff) to measure systolic blood pressure as a means of
determining whether a suspect was lying during an interrogation. Marston firmly believed that
proper interrogation techniques must be used along with technology in order to acquire accurate
lie detection results. (An interesting side note: Marston also created the comic book characterWonder Woman.)
John Larson, who followed Marston’s work, was a University of California medical student and
an employee of the Berkley police department. In 1921, Larson invented the first instrument
capable of continuously recording blood pressure, respiration, and pulse rate. The machine,
which he called a cardio-pneumo-psychogram, documented all this information on a drum of
paper. To be used along with the machine, he also developed an interview technique called the
R/I (Relevant/Irrelevant) procedure. His technique mixed questions relevant to the crime with
questions that were irrelevant. This was based on the theory that an innocent person would have
a similar physiological response to both types of questions, while a guilty person would react
more intensely to the relevant questions that focused on the crime.
Despite the use of the lie detector test in police interrogation, the courts did not consider its
results admissible. In 1923, a federal court upheld the murder conviction in Frye vs. United
States, in which the defendant had appealed on the basis that testimony from an examiner
regarding a lie detector test that Frye had passed was not accepted as evidence. The court ruled
that expert evidence would only be admitted once it had gained general acceptance.
Leonarde Keeler was fascinated by John Larson’s work. He spent much of the early 1920s
working to understand and improve the science of lie detection. Keeler used Larson’s machine as
a starting point, eventually designing a new machine that he called the emotograph. Keller added
a kymograph, which rotated the drum of paper at a regular speed beneath the pens. He also improved the recording of the data from the pneumographic tubes that wrapped around the
suspect’s chest and abdomen in order to measure the rate and depth of breath. The biggest
change Keeler installed was a psychogalvanometer, the same device that B. Sticker had
experimented with in 1897, to measure the resistance of the skin to small electrical currents
emitted through metal electrodes attached to two of the suspect’s fingertips. This last addition is
what credits Keller with creating the modern lie detector.
Sometime in 1924 or 1925, Keeler’s handmade emotograph was destroyed in a fire. August
Vollmer, an acquaintance and chief of police at the Berkley Police Department, soon brought
Keeler to William Scherer of the Western Electro Mechanical Company. Following Keeler’s
written plans and instructions, Scherer developed a mechanical metal bellow, a motor drive, a
pneumograph to go around the chest, and a mechanical indicator to mark the graph when a
question was asked. This new polygraph machine was then encased in a mahogany traveling
Leonarde Keeler’s and William Scherer’s machine was the first mass produced lie detector /
polygraph. In the first three months, they sold between 60 and 80 of these new polygraphs to
police departments all over the U.S.
Keeler’s polygraph machine was featured in a 1938 ad for Gillette razors
to show a man’s positive reaction to using the razor.
Leonarde Keeler’s patent ran out in the late 1930s, after which time the government and private
businesses took over in further advancing the technology. The basic technology has remained the
same, though the equipment is now computerized and more sensitive.
The use of the polygraph remains controversial. Physiological changes caused by emotional
factors (guilt, fear, anxiety) can be remarkably similar to those of deception. Also, poorly
phrased questions can be misleading and confusing for the person being tested. For the most part,
lie detector tests remain legally inadmissible.
Leonarde Keeler opened the Keeler Institute, which was the first polygraph school. He worked as a private polygraph consultant until his death in 1949.