What happened to Parson's Pupils?

[Scientivore]

A similar question has come up before about characters' sometimes mitten-hands. I think that it's just that Jamie is using an emotional art style for Erfworld. Details are there when they're important and gone when they're not. An eye only needs one color to show that it's open. Adding a second color is enough to show the direction that the character is looking. I haven't studied drawing but I think that it takes a fully depicted eye to show how far into the distance a character is focusing.

I've heard that other primates have dark eyes (no white) and don't follow their fellows' eyes to see what they're looking at. I've also heard that we have considerable brain power set aside just for interpreting people's bodies, then another big chunk just for faces, then another just for eyes. Where other people are looking is so unusually important to us as a species that it has apparently affected the biology of our eyes and our brains.