Fundamentals of Polygraphy

Table of Contents

The polygraph is a device that measures and records a variety of physiological indicators, such as blood pressure, pulse, respiration, and skin conductivity, during questioning. The name is derived from the Greek words “poly” (many) and “graphos” (writing). Essentially, you can derive the meaning of “many writing” which is rather accurate since the machine records the various physiological responses already mentioned.

Polygraphy is the procedure used to attempt to detect deception with the use of the polygraph instrument. This is based on the theory that deceptive answers will give readings that are markedly different from honest ones.

In some countries, this is used to interrogate criminal suspects by investigators and candidates for sensitive jobs by human resource teams.

However, it must be noted that the American Psychological Association has stated that “most psychologists agree that there is little evidence that polygraph tests can accurately detect lies.” Hence, calling it a “lie detector” is rather a misnomer, or wrong naming.

Significant Personalities in Polygraphy

Jacques D’Arsonval

His contributions aided in the development of the galvanometer
Christian Hans Stoelting

Founded the Stoelting Corporation in 1886, the leading product supplier on physiological, psychological, and psycho-physiological measurement
Angelo Mosso

Developed the first neuroimaging technique, “human circulation balance” – forerunner of the fMRI and PET
James Mackenzie

Scottish cardiologist, pioneer in the study of cardiac arrythmias; developed the ink-writing polygraph
Dr. Cesare Lombroso

First to have successfully used the hydrosphygmograph as a means for distinguishing truthfulness from deception in crime suspects
George Sticker

Theorized that the galvanic skin phenomenon was influenced by existing mental impression
Otto Veraguth

First to use the term “Psychogalvanic Skin Reflex”, an idea that the electrical phenomenon was due to the activity of the sweat glands
Vittorio Benussi

Successfully detected deception with a pneumograph, studied optical illusions, and credited with conducting extensive research into unconscious mental phenomena
Dr. William Moulton Marston

Invented the discontinuous systolic blood pressure test which became a component of the modern polygraph
John A. Larson

Developed what many consider to be the original lie detector
John E. Reid

Developed the Control Question Technique (CQT) and contributed the Reid Technique method of interrogation
Leonarde Keeler

Worked to devise a polygraph that used ink pens for recording the relative changes in a subject’s blood pressure, pulse rate and respiratory patterns

Timeline of the Modern Polygraph

infographic showing the timeline of the development of the modern polygraph machine

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