Practised liars can beat the polygraph machine by tensing muscles during the neutral questions.

Question

Quizplus · Accepted Answer

It is true that practised liars can beat the polygraph machine by tensing muscles during the neutral questions. This is because the machine measures physiological responses such as changes in heart rate, blood pressure and sweating, and if a person can control their physiological responses during the control questions, they may not show any significant differences during the relevant questions. Thus, the polygraph test is not always 100% accurate and can be manipulated by people who know how the machine works.

Practised Liars Can Beat the Polygraph Machine by Tensing Muscles