lie detector

detector

 [de-tek´ter]

a device by which an object or condition can be discovered.

image detector any recording medium used in radiology, such as film or a cathode ray tube.

lie detector polygraph.

pol·y·graph

(pol'ē-graf),

1. An instrument to obtain simultaneous tracings from several different sources; for example, radial and jugular pulse, apex beat of the heart, phonocardiogram, electrocardiogram. The ECG is nearly always included for timing.

2. An instrument for recording changes in respiration, blood pressure, galvanic skin response, and other physiologic changes while the person is questioned about some matter or asked to give associations to relevant and irrelevant words; these physiologic changes are presumed to be indicators of emotional reactions, and thus whether the person is telling the truth. Synonym(s): lie detector

[poly- + G. graphō, to write]

Commonly called a lie detector. An instrument that measures and records a test subject’s sympathetic nervous system responses—pulse, blood pressure, galvanic skin conductance due to sweating, breathing rhythms, and temperature—to a series of questions, on the premise that true and false answers produce distinctive patterns of response.

lie detector

Psychology A device that detects chest and abdominal movement during respiration, heart rate, BP, and galvanic skin conductance due to sweating. See Polygraph test.

pol·y·graph

(pol'ē-graf)

1. An instrument for obtaining simultaneous tracings from several different sources (e.g., radial and jugular pulse, apex beat of the heart, phonocardiogram, electrocardiogram). The electrocardiogram is nearly always included for timing.

2. An instrument for recording changes in respiration, blood pressure, galvanic skin response, and other physiologic changes while the subject is interviewed or asked to give associations to relevant and irrelevant words; the physiologic changes are presumed to be emotional reactions, and thus indicative of whether the subject is telling the truth.
Synonym(s): lie detector.

[poly- + G. graphō, to write]

lie detector

A popular terms for the polygraph—a collection of devices used to monitor and record various parameters of the body, such as the pulse rate, the blood pressure, the evenness and rate of breathing and the moistness, and hence the electrical resistance, of the skin. These vary with the state of the emotions and the results can be thought to cast light on significance to the subject of certain questions or statements. Emotional responses do not, however, necessarily indicate that the subject is lying or concealing the truth. Lie detection is a function of the interpreter, not the machine and it is the sensitivity, intelligence, imagination and experience of the operator that determines the forensic value of the procedure. This should always be challenged if lie detector evidence is used in court.