The polygraph cannot detect if a person is lying, only whether the person is experiencing a change in physiological functioning.

Question

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The polygraph measures changes in physiological functioning, such as heart rate and sweat gland activity, but these changes can be caused by factors other than lying, such as stress or anxiety. Therefore, the polygraph cannot definitively determine whether a person is lying or not.

The Polygraph Cannot Detect If a Person Is Lying, Only