WHAT IS A POLYGRAPH?
A polygraph, used for the purpose of lie detection, is an instrument that monitors and records various manifestations of changes in blood pressure, pulse rate, electrodermal activity, and respiration. It may also include additional components to monitor blood volume and motion.
The term “polygraph” derives from the Greek words poly (many) and graph (writing) — meaning “many writings.” The name refers to the manner in which selected physiological activities of the Sympathetic and Parasympathetic Nervous Systems are simultaneously collected, measured, and recorded while a series of carefully designed questions are asked of the person attached to the instrument.
A polygraph (also known as a lie detector) is a scientific diagnostic instrument used by a forensic psycho-physiologist (polygraph examiner) to administer a polygraph examination for the purpose of verifying the truthfulness of a person’s statement regarding a specific issue or issues.






