Definition

1. Noun:
   • A device used to detect deception: A lie detector is an instrument that measures and records physiological indicators such as heart rate, blood pressure, respiration, and skin conductivity while a person answers questions. The underlying theory is that telling a lie produces measurable physical stress responses.
   • A polygraph: This is the most common technical term for a lie detector, referring to the specific machine used in polygraph tests.

Usage Examples

• Noun:
  • The suspect was asked to take a lie detector test. (The suspect was required to undergo an examination using the device.)
  • The results from the lie detector were presented as evidence in the hearing. (The data recorded by the device was used in the legal proceeding.)

Advanced Usage

• "to administer a lie detector test": to conduct or perform the examination using the device.
  • The agency will administer a lie detector test to all new applicants.
• "to pass/fail a lie detector test": to produce results that are interpreted as indicating truthfulness or deception, respectively.
  • He was nervous but confident he would pass the lie detector test.

Variants and Related Words

• Polygraph (n): The formal, technical term for a lie detector machine.
  • The examination is officially called a polygraph examination.
• Polygrapher (n): A person who operates a polygraph/lie detector.
  • The polygrapher calibrated the machine before the test.

Synonyms

• Polygraph: The direct technical synonym.
• Deception detector: A less common descriptive term.

Notes on Meaning

• The term "lie detector" is a common name, but it is important to note that the device does not directly detect lies. It records physiological changes that an examiner interprets as potential signs of stress related to deception. Its accuracy and admissibility as evidence are subjects of ongoing debate.

Noun

1. a polygraph that records bodily changes sometimes associated with lying