Neanderthals and fossil Homo sapiens living at the same time had equal brain volume. A new study shows, though, that Neanderthals had larger eye sockets – and a larger brain area devoted to sight – than in modern humans. When the larger visual system is subtracted from total brain size, our extinct cousins actually had a smaller rest of the brain than did fossil Homo sapiens.
In living primates, the brain’s visual system corresponds to the size of the eye socket. Calculating brain size in fossil humans with this information, the remaining brain area in Neanderthals was about 15% smaller than in fossil modern humans. According to the researchers, this difference may relate to greater social complexity in Homo sapiens – potentially an important distinction between the two species, who co-existed 200,000 to 30,000 years ago.
This research, led by E. Pearce of the University of Oxford, England, was published in Proceedings of the Royal Society B, March 13, 2013.
Image below: Homo sapiens (Cro-Magnon, left) and Homo neanderthalensis (Amud, right): Despite having the same total brain volume, the large eyes of Neanderthals suggest that less of the brain focused on other mental tasks.