Human evolution; brain case size unchanged recently (Introduction)

by David Turell , Monday, August 01, 2022, 21:32 (632 days ago) @ David Turell

No change for 200,000 years, but brain shape does change:

https://www.newscientist.com/article/2331652-shape-of-human-brain-has-barely-changed-in...

"The physical transformation of the human cranium over the past 160,000 years was probably driven by alterations in the face resulting from diet and lifestyle changes, not from the evolution of the brain itself as previously thought, a study has found.

"The cranium, or braincase, of early modern humans dating back 200,000 years isn’t much different in size from those today, but has a significantly different shape, suggesting that the brain has become rounder over time.

"The leading hypothesis is that changes in behaviour, such as the development of tools and art, caused the shape of the Homo sapiens brain to change and, in turn, the skull that protects it. (my bold)

***

{"The team was surprised to find that while the size and proportions of the skulls of H. sapiens children from 160,000 years ago were largely comparable to infants today, the adults looked remarkably different to those of modern adults, with much longer faces and more pronounced feature

***

"If the fossil children – with near fully developed brains – resemble living ones, but fossil adults had very different skulls, we can rule out that brains have changed significantly in shape, says Zollikofer. “And if it’s not the brain driving this change, we must look for something else, like breathing, eating or moving.”

***

"Faces in modern humans are far smaller, with subtler indentation, than those of their ancestors. Studies show that this change accelerated when hunter-gatherers became agriculturalists around 12,000 years ago and ate softer foods, probably due to less loading on the skull from chewing."

Comment: so, the brain shape changed, undoubtedly due to our new uses of it with complexification and shrinkage as a result. No evidence for dhw's weird anatomic theory that a larger skull could not be accommodated.