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Article: Polygraphs
- Article from:
- Encyclopedia of Espionage, Intelligence, andSecurity
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CopyrightCOPYRIGHT 2004 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Polygraphs
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JULI BERWALD
A polygraph test is administered to determine whether or not statements made by the subject taking the test are deceptive. During the test, the subject is monitored by a polygraph machine and interrogated by an administrator trained in forensic psychophysiology. The machine measures changes in the subject's blood pressure, heart rate, respiration rate and sweat production. The theory underlying the polygraph test is that a person who is lying exhibits involuntary physiological responses that can be detected by the polygraph instrument. These changes include rapid breathing and heartbeat and increased blood pressure and perspiration.
The Polygraph ...