Welcome to season two of Flash Forward! We kicked off this season with a pretty unlikely future: the entire world goes face blind. In the episode we discuss what causes face blindness — also known as prosopagnosia — and the tricks that people use to remember their friends. We also go through all the things that would be easier (spying, hiding) and harder (police lineups, cocktail parties) in a world where we were all faceblind. Today, about two percent of the population has some form of face blindness, or prosopagnosia. Some people with prosopagnosia have a hard time with acquaintances, while others struggle to recognize their own family members, and sometimes even themselves. If after this you’re thinking “hm, I wonder if I’m face blind,” you can take an unofficial online test here. To figure out what this world might be like, I called up Dr. Jason Barton, a neurologist at the University of British Columbia who treats and studies people with face blindness. He told me that face blindness can happen for a…