In aged China, a measure 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, while the Middle Ages, torture was used as a means of forcing a man to tell the truth. Ken Adler's article To Tell the Truth: The Polygraph Exam and The Marketing of American Enterprise states that the convention of torture was rooted in the system 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 contemporary Criminology Cesare Lombroso, became the first man to use science as a method of detecting deception. Lombroso used devices called the plethysmograph and the sphygmograph. The conjecture wore an airtight volumetric glove that was attached to a rubber membrane. This activated a pen that rolled over the outside of a smoked drum. The speed of the pen varied with the suspect's blood flow. Lombroso believed that, when a man 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 examiner would see when and if the conjecture was lying.
The next progress came in 1897, when B. Symbol developed a method of measuring the whole of sweat a conjecture produced while interrogation. This was determined by the electrical conductibility of the suspect's skin.
The first "polygraph" motor was genuinely a copy motor 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 gismo wrapped nearby the person's chest and measured depth and rate of breath. Eugene Levitt, in his article The Scientific assessment 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 related to the act of deception.
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 a sphygmomanometer (blood pressure cuff) to measure systolic blood pressure as a means of determining whether a conjecture was lying while an interrogation. Marston firmly believed that permissible interrogation techniques must be used along with technology in order to acquire spoton lie detection results. (An fascinating side note: Marston also created the comic book character Wonder Woman.)
John Larson, who followed Marston's work, was a University of California medical pupil 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 facts 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 system that an innocent man would have a similar physiological response to both types of questions, while a guilty man would react more intensely to the relevant questions that focused on the crime.
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 motor as a starting point, at last designing a new motor that he called the emotograph. Keller added a kymograph, which rotated the drum of paper at a quarterly speed beneath the pens. He also improved the recording of the data from the pneumographic tubes that wrapped nearby 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 gismo that B. Symbol had experimented with in 1897, to measure the resistance of the skin to small electrical currents emitted straight through metal electrodes attached to two of the suspect's fingertips. This last increasing is what due Keller with creating the contemporary lie detector.
Sometime in 1924 or 1925, Keeler's handcrafted 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 nearby the chest, and a mechanical indicator to mark the graph when a inquire was asked. This new polygraph motor was then encased in a mahogany traveling case.
Leonarde Keeler's patent ran out in the late 1930s, after which time the government and incommunicable businesses took over in added advancing the technology. The basic technology has remained the same, though the tool 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 man being tested. For the most part, lie detector tests remain legally inadmissible.
