Question

It is well established that certain autonomic responses such as heart rate, perspiration, and respiration change under stress. In view of the fact that people generally have stronger autonomic responses when lying than when telling the truth, it follows that the polygraph would be a foolproof approach to lie detection. Which statement best explains why the polygraph is not more widely used in courtrooms and in testing of job applicants?

Answer 1

Answer:

Psychological arousal is very simimal for several emotions, so it is not always reliable for the polygraph to distinguish one emotion reaction from another. For instance guilt from other reactions.

Explanation:

The polygraph can most certainly determine if a person is nervous or not, because the nervous system reacts under testing situations, as well as other body reactions. This is not sufficient enought to deternmine wether someone is lying or not, is guilty or not. Someone can be nervous, and the polygraph can identify it, but this does not neccesarily mean a person can be found guilty.