Visual pathways used to be simple - there was a "what" pathway and a "where" pathway. What does it mean to include "who" and "how" pathways? How have those additional components expanded our understanding of the dorsal and ventral streams? Can we explain how "who" cells develop for unusual faces or objects, like Jennifer Aniston or a toilet brush? Seriously, we have Jennifer Aniston cells. And monkey cortices were found to have cells dedicated to toilet brushes. Look it up if you don't believe me.