History of the polygraph instrument | Polygraph and lie detection

Polygraph instrument

History of polygraphy. The first instrument that could be called a polygraph was invented by John Larson in 1921.

However, lie detection had become popular due to a famous case prior to John Larson’s first polygraph instrument. William Moulton Marston had previously applied a lie detection test using systolic blood pressure measurement to help free, Frye, which had been convicted for a murder.

Actually, this case became more famous than John Larson’s invention as it became a landmark case for the use of scientific evidence. In the case known as Frye vs. United States. Associate Justice, Van Orsdel, decided that expert testimony must be based on scientific methods that are sufficiently established and accepted and therefore confirmed that the test presented by Marston had rightly been denied by the judging court.
The polygraph instrument as well as the testing methodology has seen important improvements since the times of Larson and Marston.

Polygraph history

Important milestones for the instrument were the further inclusion of sensors but also improvements made to the instrument, possible with the evolution of technology.

In 1938 Leonard Keeler for example added the galvanometer to the instrument. John Larson employed a pneumograph and a blood pressure sensor to gather physiological data from the examinees.

Electronics made it possible to have portable polygraphs, allowing experts to travel with their devices and apply their art in different places in the country.

Digitalization was the next big revolution and digital polygraph instruments made it even easier to transport and share data. This also triggered the interest for polygraphy in other parts of the world, outside the United States.

In India polygraph testing, lie detector testing is of common use and the authorities apply this type of tests all over the country.

Polygraph India focuses on the private sector and we apply this science all over the country.

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