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Daniel Defoe's Essay "An Effectual Scheme for the Immediate Preventing of Street Robberies and Suppressing all Other Disorders of the Night"
In the essay, he recommended taking the suspects pulse in a of distinguishing truth from lies. (Accurate date is unknown). -
The Plethysmograph was invented.
It was in 1878 that science first came to the aid of truthseeking. It was then that an instrument called a plethysmograph was used in research on emotion and fear in subjects undergoing questioning. It studied the cardiovascular and respiratory systems. -
The Clinical Polygraph was invented.
The Clinical Polygraph was invented by Sir James Mackenzie but not for detecting deception. It was used for medical examinations as a way of recording and documenting the vascular pulses. (Accurate date unknown.) -
The First Polygraph
The first means of a instrument designed to measure physiological responses for this purpose came in 1895. Cesare Lombroso changed an existing instrument called a hydrosphygmograph and used this new device in experiments to measure the physiological changes that happened in a criminal suspect's blood pressure and pulse during an interrogation. -
The Pneumograph was invented.
An Italian psychologist Vittorio Benussi discovered a way of calculating the difference of the inhalation to exhalation time as a way of verifying the truth and detecting deception in a suspect. He used this device, naming it the pneumograph, to conduct experiments on the way deception affected breathing patterns. -
An early version of the lie detector test.
Dr. William Moulton Marston, an attorney and psychologist, is credited with inventing an early version of the lie detector when he came up with the discontinuous systolic blood pressure test which would later become a part of the modern polygraph -
The Original Lie Detector Test
John A. Larson, a psychologist, developed what many would consider to be the original lie detector test when he added respiration rate to that of blood pressure. He named his device the polygraph. Using his device, he was the first person to continually measure changes in a suspect's pulse rate, blood pressure and respiratory rate during an interrogation. His polygraph was used frequently, and with much success, in criminal investigations. -
The Keeler Polygraph
Leonarde Keeler patented what is now known as the prototype of the modern polygraph — the Keeler Polygraph. Today, Leonarde Keeler is known as the father of polygraph.
