MODEL RELEASED. Lie detector test. Man undergoing a lie detector, or polygraph, test. The polygraph is the metal machine in front of the examiner. It records changes in a number of physiological processes, as a series of questions are asked by the examiner. Around the subjects left arm is a cuff to measure blood pressure and around his chest are air-filled bands (pneumographs), which measure the movement of the chest with each breath. Pulse meters (not seen) are also attached to the subjects fingers to measure heart rate. The examiner interprets the results to determine if the subject demonstrated deceptive behaviour. The reliability of polygraphs is controversial and their evidence is not admissible in court.