Polygraph tests, also known as lie detector tests, are devices that measure and record several physiological indicators such as blood pressure, heart rate, respiration, and skin conductivity while a person is being asked a series of questions. The assumption is that lying will produce physiological responses that can be detected by the polygraph.
Polygraph tests have been used for over a century, but their accuracy and reliability have been the subject of much debate. Some studies have shown that polygraph tests can be accurate in detecting deception, while other studies have found that they are not. There are a number of factors that can affect the accuracy of a polygraph test, including the skill of the examiner, the type of questions being asked, and the emotional state of the person being tested.