Neanderthal brain size at birth provides insights into the evolution of human life history

Neanderthal brain size at birth provides insights into the evolution of human life history.

Ponce de León MS, Golovanova L, Doronichev V, Romanova G, Akazawa
T, Kondo O, Ishida H, Zollikofer CP.

Anthropological Institute and Museum, University of Zurich,

From birth to adulthood, the human brain expands by a factor of 3.3, compared with 2.5 in chimpanzees [DeSilva J and LesnikJ (2006) Chimpanzee neonatal brain size: Implications for brain growth in Homo erectus. J Hum Evol51: 207-212]. How the required extra amount of human brain growth is achieved and what its implications are for human life history and cognitive development are still a matter of debate. Likewise, because comparative fossil evidence is scarce, when and how the modern human pattern of brain growth arose during evolution is largely unknown. Virtual reconstructions of a Neanderthal neonate from Mezmaiskaya Cave (Russia) and of two Neanderthal infant skeletons from DederiyehCave (Syria) now provide new comparative insights: Neanderthal brain size at birth was similar to that in recent Homo sapiens and most likely subject to similar obstetric constraints. Neanderthal brain growth rates during early infancy were higher, however. This pattern of growth resulted in larger adult brain sizes but not in earlier completion of brain growth. Because large brains growing at high rates require large, late-maturing, mothers [Leigh SR and Blomquist GE (2007) in Campbell CJ et al. Primates in perspective; pp 396-407], it is likely that Neanderthal life history was similarly slow, or even slower-paced, than in recent H. sapiens.

I keep getting conflicting information on Neanderthal growth rates. One tooth study suggested it was the same as modern humans, another that it was faster. Now this suggests it was slower. I suspect it wasn’t a lot different.

2 responses to “Neanderthal brain size at birth provides insights into the evolution of human life history

  1. You know, I’m not even sure how the relative brain size and growth rate affects our understanding of HN intellect or cognitive ability – it’s quite possible that very large brains or similarly-sized brains could not achieve what our brains could and can because of structural differences in our brains. It’s too bad soft parts don’t fossilize so well.

    I wonder what assumption underlies such studies: is the growth-rate in any way an indication of HN intelligence and mental faculties? How can we deduce such conclusions?

  2. And is intelligence the defining characteristic of modern humans? I suspect this emphasis on human brains is more a product of the fact that most people who study anthropology are themselves academics and so regard intelligence as being more important than it actually is.

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