Monday, June 7, 2010

Face to face with the social brain

Just got an article entitled "Correlated evolution of brain regions involved in producing and processing facial expressions in anthropoid primates" accepted in Biology Letters (co-authored with Chet Sherwood). Here's the abstract:

Anthropoid primates are distinguished from other mammals by having relatively large primary visual cortices (V1) and complex facial expressions. We present a comparative test of the hypothesis that facial expression processing co-evolved with the expansion of V1 in anthropoids. Previously published data were analyzed using phylogenetic comparative methods. The results of our study suggest a pattern of correlated evolution linking social group size, facial motor control, and cortical visual processing in catarrhines, but not platyrrhines. Catarrhines that live in relatively large social groups tended to have relatively large facial motor nuclei, and relatively large primary visual cortices. We conclude that catarrhine brains are adapted for producing and processing complex facial displays.
*UPDATE (6/30/10): The publisher's version is online here (subscription required until 2/23/12). Contact me if you want a PDF.