The social brain hypothesis and its implications for social evolution

@article{Dunbar2009TheSB,
  title={The social brain hypothesis and its implications for social evolution},
  author={Robin I. M. Dunbar},
  journal={Annals of Human Biology},
  year={2009},
  volume={36},
  pages={562 - 572}
}
The social brain hypothesis was proposed as an explanation for the fact that primates have unusually large brains for body size compared to all other vertebrates: Primates evolved large brains to manage their unusually complex social systems. Although this proposal has been generalized to all vertebrate taxa as an explanation for brain evolution, recent analyses suggest that the social brain hypothesis takes a very different form in other mammals and birds than it does in anthropoid primates… 
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