My question is, if one is not nervous about answering a question falsely, can the polygraph pick up the lie?  From what I understand there are only two ways a polygraph works 1. To try and scare the examinee into disclosing info out of fear that the test can actually tell when a person lies.  2. To convince the examinee that the examiner already knows the real truth or can easily find out therefore causing the examinee to become anxious and trigger the flight or fight response; in turn spiking their heart rate raising their blood presser and doing what ever else the body does and causing a elevated or change on the machine. Am I right?   Or am totally off base?   If I am right then if the examinee knows that the polygraph can’t really pick out a lie from the truth and they know with out any doubt that the examiner does not know the truth and can never find out then to answer falsely should not cause and reaction in the body or brain at all.  And if this is true how can people say that this is a proven tool to catch lie?  The science does not add up.  But I could be way off..   Thoughts?