The Pixar guys are all about Desmond Morris (every animator online recommends his books) Anyway, Spline Doctors just threw up a link to one of the documentaries about hand gestures. Interesting how he breaks it down (though I don't think I buy into some of the reasoning "beating you over the head with his symbolic tiny club"?) The fifth of this show talks about facial expressions. (Tracing the roots from chimps. Starting to lean towards Paul Ekman and his 7 universal facial expressions (you know, what that silly show Lie to Me is exaggerating))
Anyway, worth a watch, might check out the other episodes available on youtube.