That I very much agree with.  I do believe he was very biased. He made the statement to my husband that he was there to help "people like him." To me that is a red flag that he stereotyped him before he even did the examination. He said that he works with several psychologists so that he can "understand people who lie." However he possess no degree in this.  That is the school of thought that nurture wins out over nature. However, that is not the case, who a person is is affected by both.  I also found out after the test that the person that administered it, was himself a police officer in the same county and has lived here all his life.  Could that not be a conflict of interest? He was not an outside unbiased source to begin with, he interacts with other officers on a daily bases.

Sure, but any number of other factors, including examiner bias, could also have influenced the outcome of the polygraph examination.

Your french is just fine!  I understand what you are saying with body reactions being measured.  I remain in the school of thought that a vast array of situations could alter a polygraph test. However, I do believe that our bodies react unconsciously to situations.  So, if that is what is measured, not actual brain activity but body reaction; Could his brain have cause his body to react when asked the question because he had "relived" it so many times?

Pardon my French, but the polygrapher's story about a "switch in the brain" is complete and utter bullshit that he pulled out of his ass. The polygraph measures respiration, skin conductance (or resistance), heart rate and blood pressure (kinda sorta). It doesn't measure brain activity. And in any event, none of the indices recorded by the polygraph are correlated with deception in a systematic way.

It's pointless to try to divine why an invalid procedure (polygraph "testing") may have produced inaccurate results. It's like trying to determine why a coin toss turned out heads instead of tails.

See The Lie Behind the Lie Detector for a documented debunking of polygraphy:

https://antipolygraph.org/lie-behind-the-lie-detector.pdf

Today my husband had to take a polygraph test and he "failed" it.  It was explained to him by the examiner that there is a "switch" in your brain that  unconsciously puts a person back into the situation that they did and that is how the brain shows you are lieing. He said that an innocent person does not go back to a place that they haven't been.  I could see this as a truth being a student of Psychology myself.  However, my question is could the fact that my husband relived what he was being accused of because it was in our own home.  Several dozen times he played out the story step by step to others to show that it was not possible.  Could the playing out of it to others unconsciously made his brain think he was actually there?