Sunday, May 31, 2009

Social animals

Time magazine has a interesting article up about the correlation between social animals and brains size.

Social Animals: Not Necessarily Brainier

Being social isn't for dummies. Animals that gather into packs, herds or troops — never mind into cities and countries — need to be smart. How else to negotiate the complex rules and hierarchies of their cultures? It's not for nothing that sharks, among the dimmest of the large carnivores, are loners, or that humans — far and away the smartest — are so enthusiastically collectivist.

What this ought to mean is that social animals have bigger brains than solitary ones, and the research has indeed suggested as much. A landmark 2007 paper called "Social Brain Hypothesis," published in the journal Evolution, showed that increased sociality was linked to steadily bigger brains in at least three orders of mammals: primates like us, carnivores like lions and ungulates like zebras and bison.

That widely accepted truth might be coming undone, however, thanks to a new study published in the Proceedings of the National Academy of Sciences. According to the authors, evolutionary biologists John Finarelli of the University of Michigan and John Flynn of the American Museum of Natural History, there's a much murkier link than we thought between big brains and big societies. As it turns out, it was our favorite nonhuman critters — dogs — that threw off previous data.

Finarelli and Flynn only focused on carnivores when looking at this, so the study is not as broad as earlier studies (like the 2007 study mentioned), but it goes into more dept in one area, studying not only the living species but also the fossil record.

The study is unfortunately behind PNAS' paywall, but the abstract can be found here: Brain-size evolution and sociality in Carnivora

I highly recommend the Time article, which is pretty well written, and which explains the research quite well.

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