Physiology

general nervous tension

General nervous tension (GNT) describes physiological patterns suggesting the examinee's basal Arousal level is elevated — fast heart rate, labile electrodermal activity, and uneven breathing. GNT is not indicative of deception in itself. Examiners attempt to bring the examinee to a moderate arou...

What Is General Nervous Tension?

General nervous tension (GNT) refers to the overall elevated physiological arousal that examinees may experience during a polygraph examination due to the testing situation itself — anxiety about the process, unfamiliarity with the equipment, awareness of the stakes — rather than in response to specific questions. GNT is a non-specific state that affects all physiological channels and can elevate Baseline Arousal">baseline arousal across the entire examination.

Impact on Polygraph Data

GNT presents a challenge for polygraph testing if it is severe enough to mask or distort the question-specific differential responses that scoring systems evaluate. An examinee with extremely high general tension may produce elevated responses to all questions — relevant, comparison, and irrelevant — making it difficult to identify the differential pattern that distinguishes deceptive from truthful responding.

How CQT Addresses GNT

The Comparison Question Technique is designed to function despite GNT because it evaluates relative (within-subject, between-question-type) differences rather than absolute response magnitudes. Even with elevated general tension, the examinee’s psychological set still directs their greatest concern to whichever question type is most threatening — relevant questions for deceptive examinees, comparison questions for truthful ones — preserving the differential pattern.

Examiner Management

Examiners reduce GNT through a thorough pre-test interview, explaining the process, answering questions, reviewing all test questions, and establishing rapport. The stimulation test also helps by familiarising the examinee with the testing procedure.