How is the Polygraph Examination conducted?

A Polygraph (popularly referred to as a Lie-Detector) is an instrument that measures and records physiological changes caused by the sympathetic nervous system, while the subject is asked a series of questions for which he has to answer “yes” or “no”, wherein deliberate lying produces bodily reactions reflected in blood pressure, respiration (breath rate), skin sensitivity etc. measured through the couplings made to the body of the person.