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History of the Polygraph

  • The polygraph machine ancestor was built

    The polygraph machine ancestor was built
    Angelo Mosso used an instrument called a plethysmograph to detect the change in blood pressure in response to certain stimuli.
  • First clinical polygraph was constructed

    First clinical polygraph was constructed
    The doctor James Mackenzie constructed the first polygraph. An instrument that could be used during medical examinations.
  • The first use of a scientific instrument to measure physiological responses

    The first use of a scientific instrument to measure physiological responses
    Cesare Lombroso, modified an existing instrument called a hydrosphygmograph and used it to measure physiological changes in the blood pressure and pulse of a suspect questioned by the police.
  • Systolic blood pressure test was designed

    Systolic blood pressure test was designed
    Dr. William Moulton Marston invented a primitive form of lie detector, the blood pressure test is a component of the modern polygraph
  • The polygraph is officially used

    The polygraph is officially used
    John A Larson a employee of the Police of California created the original polygraph. His instrument provided continuous readings of blood pressure.
  • The prototype of modern polygraph was constructed

    The prototype of modern polygraph was constructed
    Leonarde Keeler patented what is considered the prototype of the modern polygraph
  • Start the computer age of the polygraph

    Start the computer age of the polygraph
    A software called PolyScore is used to analyze the data generated by the polygraph.