What is "polygraph"

Polygraph \Pol"y*graph\, n. [Gr. ? writing much; poly`s much, many + ? to write: cf. F. polygraphe.]

1. An instrument for multiplying copies of a writing; a manifold writer; a copying machine.

2. In bibliography, a collection of different works, either by one or several authors.
   --Brande & C.

1794, "mechanical device for making multiple copies of something written or drawn," from Greek polygraphos "writing much," from polys "much" (see poly-) + graphos "writing," from graphein "to write" (see -graphy).\n

\nMeaning "instrument for recording several pulsations of the body at the same time" is 1871; first used as a lie detector 1921. Related: Polygraphy (1590s); polygraphic (1771).

n. 1 A device which measures and records several physiological variables such as blood pressure, heart rate, respiration and skin conductivity while a series of questions is being asked to a subject, in an attempt to detect lies. 2 (context dated English) A mechanical instrument for multiplying copies of a writing, resembling multiple pantographs. 3 (context archaic English) A collection of different works, either by one or several authors. vb. To administer a polygraph test.

n. a medical instrument that records several physiological processes simultaneously (e.g., pulse rate and blood pressure and respiration and perspiration)

A Polygraph is a device that produces a copy of a piece of writing simultaneously with the creation of the original, using pens and ink.

Patented by John Isaac Hawkins on May 17, 1803, it was most famously used by the third U.S. president, Thomas Jefferson, who acquired his first polygraph in 1804 and later suggested improvements to Charles Willson Peale, owner of the American rights. Because Jefferson was a prolific letter writer, the preservation of his copies have offered historians extensive insights into Jefferson's viewpoints and actions. Jefferson called the polygraph "the finest invention of the present age". A description of Jefferson's office routine in his own words may be read here.

Another American, Benjamin Henry Latrobe was the first customer of Peale's and not only introduced the device to Jefferson but was also instrumental in its improvement.

The quality of the copy made by a machine in good condition is so fine that it is considered by some that only characteristics other than the quality of the script (e.g., having been mailed, etc.) are reliable indicators (under the assumption that the original was mailed and not the copy), although a worn or maladjusted machine will produce specific indications in the copy.

Mechanisms of this type are more generally known as pantographs, which include simple devices for making copies at various enlargements or reductions by tracing over a drawing.

A polygraph (from Ancient Greek: πολύς, poly = "many" and γράφειν, graphein = "to write") is an author who writes in a variety of fields.

In literature, the term polygraph is often applied to certain writers of antiquity such as Aristotle, Plutarch, Varro, Cicero and Pliny the Elder. Polygraphs still existed in the Middle Ages and Renaissance, but, other than writers of books for children, they have become rarer in modern times due to the specialisation of knowledge. Voltaire and Diderot are examples of modern polygraphs.

Polygraph is a film by Canadian director Robert Lepage, released in 1996.

The film stars Marie Brassard as Lucie Champagne, an actress who is given the role of Marie-Claire in a film dramatizing a real-life murder, and Patrick Goyette as François, Lucie's former boyfriend who was Marie-Claire's neighbour and is a suspect in the real crime. The film's cast also includes Josée Deschênes, Maria de Medeiros, Peter Stormare, Marie-Christine Le Huu and Richard Fréchette.

In mathematics, and particularly in category theory, a polygraph is a generalisation of a directed graph. It is also known as a computad. They were introduced as "polygraphs" by Albert Burroni and as "computads" by Ross Street.

In the same way that a directed multigraph can freely generate a category, an n-computad is the "most general" structure which can generate a free n-category.

A polygraph, popularly referred to as a lie detector, measures and records several physiological indices such as blood pressure, pulse, respiration, and skin conductivity while the subject is asked and answers a series of questions. The belief underpinning the use of the polygraph is that deceptive answers will produce physiological responses that can be differentiated from those associated with non-deceptive answers; the polygraph is one of several devices used for lie detection.

The polygraph was invented in 1921 by John Augustus Larson, a medical student at the University of California at Berkeley and a police officer of the Berkeley Police Department in Berkeley, California. The polygraph was on the Encyclopædia Britannica 2003 list of greatest inventions, described as inventions that "have had profound effects on human life for better or worse."

The efficacy of polygraphs is debated in the scientific community. In 2001, a significant fraction of the scientific community considered polygraphy to be pseudoscience. In 2002, a review by the National Academies of Science found that in populations untrained in countermeasures, polygraph testing can discriminate lying from truth telling at rates above chance, though below perfection. These results apply only to specific events and not to screening where it is assumed that polygraph would work less well. Effectiveness may also be worsened by countermeasures.

In some countries polygraphs are used as an interrogation tool with criminal suspects or candidates for sensitive public or private sector employment. US law enforcement and federal government agencies such as the FBI and the CIA and many police departments such as the LAPD use polygraph examinations to interrogate suspects and screen new employees. Within the US federal government, a polygraph examination is also referred to as a psychophysiological detection of deception (PDD) examination.

Polygraph testing is designed to analyze the physiological reactions of subjects. However, research has indicated that there is no specific physiological reaction associated with lying and that the brain activity and mechanisms associated with lying are unknown, making it difficult to identify factors that separate liars from truth tellers. Polygraph examiners also prefer to use their own individual scoring method, as opposed to computerized techniques, as they may more easily defend their own evaluations.

The validity of polygraph testing is again called in to question with the relevant-irrelevant testing technique, designed to gauge reactions of subjects against crime questions and other non-crime related questions. Studies have indicated that this questioning technique is not ideal, as many innocent subjects exert a heightened physiological reaction to the crime relevant questions.

The control question test, also known as the probable lie test, was developed to combat the issues with the relevant-irrelevant testing method. Although the relevant questions in the probable lie test are used to obtain a reaction from liars, it can also gain a reaction from the innocent subject who is afraid of false detection. The physiological reactions that "distinguish" liars, may also occur in individuals who fear a false detection, or feel passionately that they did not commit the crime. Therefore, although a physiological reaction may be occurring, the reasoning behind the response may be different. Further examination of the probable lie test has indicated that it is biased against innocent subjects. Those who are unable to think of a lie related to the relevant question, will automatically fail the test.

Polygraph examiners, or polygraphers, are licensed or regulated in some jurisdictions. The American Polygraph Association sets standards for courses of training of polygraph operators, though it does not certify individual examiners.

A polygraph is a forensic instrument.

Polygraph may also refer to:

• Polygraph (author), an author that can write on a variety of different subjects
• Polygraph (duplicating device), a dual pen device that produces a simultaneous copy of an original while it is written in cursive writing
• Polygraph (mathematics), a mathematical generalisation of a directed graph in mathematics, also called a computad
• Autopen, an automatic signing instrument
• A painted reproduction created by the Polygraphic Society in London in the 1700s, by a process also known as "pollaplasiasmos"
• A 1988 play at the Theatre of Canada by Robert Lepage