Capgras and the ramechandran video

I found the Capgras phenonmenon to be the most confusing one presented in the film. The patient seemed to be completely fine and then later completly out of it, not believe that the things arounf him are truly his own, including his own parents. When given a lie detector exam, and shown photograph he had not emotional stimulation when shown pictures of his parents. But oddly enough, when they were over the phone, he believed then and only then that these were his parents.