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Polygraph (Sociology)
A device used to determine whether an individual is being truthful. Commonly referred to as a lie detector test, the instrument records the individual's physiological responses when asked specific questions; these physiological responses include measures of breathing, blood pressure, and pulse. Before being asked the questions of interest, a pretest is carried out to measure the change in physiological responses. Based on that level of change, it is possible to determine whether an individual is being truthful. Polygraphs can be used by the police when investigating suspects in a criminal case, though this material is generally inadmissible in court.