by 
The Curious Bag
-
A lie detector is scientifically known as a polygraph. It is a machine that measures people's physical responses to questions, to determine if they are telling the truth.
Measurements
A person is connected to a lie detector to measure heart rate, respiratory rate, blood pressure and body temperature. In theory, these responses will be elevated if the person is lying.
Method
The person is initially asked a series of control questions such as, "Are you married?" This records base-line levels while lying and telling the truth. The interrogation follows, and the subject's responses are continuously recorded.
Results
The results of a lie-detector test are not always black or white. They are interpreted by a specialist to determine the likelihood that the person tested is lying.
Uses
Lie-detector tests are commonly used in suspect interrogations by the police and military, and during parole hearings for sex offenders. Polygraph results are admissible in court in some U.S. states.
Controversy
The accuracy of lie-detector tests has long been disputed. A study published by the National Research Council found no validity in polygraph testing.
Source:
RELATED QUESTIONS
Copyright 2023, Wired Ivy, LLC