Fundamentals of Polygraph

Fundamentals of Polygraph

• Polygraph combines the Greek words "poly," meaning "many," and "graph," meaning "writing a chart".
• An instrument designed to record psycho-physiological changes in the body when a person is lying.

Polygraphy

• Polygraphy is a method of detecting deception using a polygraph instrument.
• Administering it involves asking questions to the subject concerning the case under investigation.

Definition of Terms

• Deception: An act of deceiving or misleading, often accomplished by lying.
• Lying: Uttering falsehoods or creating false impressions to affect the acts or opinions of others.
• Detection: Discovering the existence or presence of something hidden or obscure.
• Emotion: A reaction involving physiological changes like altered pulse rate, gland activity, or body temperature, with primary reactions being anger, love, and fear.
• Fear: Emotional response to specific dangers that may be beyond a person's defensive capabilities.
• Subject: Any person undergoing a polygraph test or examination.
• Polygraphists/Polygraph Examiner: Person conducting the polygraph test, also known as a Forensic Psychophysiologist.
• Polygraph Test/Examination: The entire process of questioning, from taking one chart to all charts and question sheets used in the test.
• Polygraph Chart/Polygrams: Recorded tracings of all emotional patterns on charts/graphs from a series of questions.
• Admission: A self-incriminatory statement of facts by the accused that doesn't directly acknowledge committing the offense.
• Confession: A direct acknowledgment of guilt for the charged offense or an essential part of the criminal acts.

Historical Development of Polygraph

• Daniel Defoe (1730) suggested "taking the pulse" in his essay as a practical method for identifying criminals.
• Angelo Mosso (1878), encouraged by Cesare Lombroso, studied emotion, fear, and respiration, using the "plethysmograph" invented by Francis Franke to measure blood pressure and pulse changes, noting changes in breathing patterns under stimuli.
• Cesare Lombroso (1895) modified the "hydrosphymograph" to determine truthfulness/deception based on blood pressure-pulse changes when questioning suspects, though the instrument was mainly for medical purposes.
• Physiological changes occur when suspects are asked about their involvement in an offense.

Inventors and their contributions

• Dr. William Moulton Marston (1915) believed verbal deception could be detected by changes in systolic blood pressure and created the systolic blood pressure deception test with a standard blood pressure cuff (sphygmomanometer) and stethoscope utilizing a Discontinued Technique.
• John A. Larson (1921) developed the "Larson Polygraph" capable of continuously recording blood pressure, pulse, and respiration in a portable form; considered the first modern polygraph and Father of Polygraph. Its first real-world application was in Berkeley, CA.
• Leonarde Keeler (1925) invented a more satisfactory instrument than Larson's, later adding a "galvanometer" for recording Galvanic Skin Reflex (GSR); devised rolled chart paper and incorporated the kymograph. Known today as the Father modern of Polygraph.
  • 1926: Keeler Polygraph introduced as an improved lie detector.
  • 1938: Psychogalvanometer added to the Keeler Polygraph.
  • 1939: Keeler patented the modern polygraph prototype: the Keeler Polygraph.
• Vittorio Benussi (1914) researched respiration changes as indicators of lying and used a Pneumograph to record breathing patterns, finding that lying caused detectable respiratory changes.
• Harold E. Burtt (1917) used Benussi's techniques, determining that respiratory changes were indicative of deception, but systolic blood pressure changes were more valuable in determining deception.
• Jacques D'arsonval (1851) declared electricity generated by the body (External Friction) asserting sweat glands store and discharge electricity, contributing to the development of the galvanometer.
• Charles Samson Fere (1888) discovered electro-dermal responses linked to increased heart action and vital energy converted with human emotions, asserting the body's ability to generate, store, and discharge static electricity.
• Luigi Galvani developed the Galvanic Skin Reflex/Galvanometer, recording electrical bodily resistance/ohms; GSR reflected emotional changes by measuring changes in skin resistance to electricity.
• George Sticker (1897) suggested using the galvanograph for deception detection, theorizing the galvanic skin phenomenon was influenced by exciting mental impressions, and introduced detecting deception from the galvanic impression on chart tracings.
• Otto Veraguth (1907) first used the term "psychogalvanic skin reflex," linking the electrical phenomenon to sweat gland activity.
• John E. Reid (1945) devised "The Reid Polygraph" for recording muscular activity alongside blood pressure, pulse, respiration, and GSR; developed Control Question Technique (CQT) in 1947, replacing RIT. CQT is now generally used and accepted.
• Sir James Mackenzie (1906) refined his polygraph and entitled his finding "The Ink Polygraph,” using a clockwork mechanism to record physiological functions more efficiently.
• Dr. Joseph F. Kubis was the first researcher to use potential computerized polygraph chart analysis in the late 1970s.
• Dr. David C. Raskin and Dr. John C. Kircher (1980) from the University of Utah introduced computer-assisted polygraph techniques and computerized polygraphs entered the market in 1992.
• Dr. Dale E. Olsen and John C. Harris (1993) completed a software program named PollyScore which used a sophisticated mathematical algorithm to analyze polygraph data; validated algorithms have exceeded 98% in their accuracy to quantify, analyze and evaluate the physiological data collected from polygraph examinations administered in real criminal cases.

The polygraph is an instrument designed to record psycho-physiological changes when a person is lying. Polygraphy is a method of detecting deception using a polygraph instrument. It involves asking questions to the subject concerning the case under investigation.