Modern human brain organization emerged only recently
sciencedaily.com
Modern human brain organization emerged only recently
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Re: Modern human brain organization emerged only recently
#2As a layperson, I find this article deficient of worthwhile information, because while it juxtaposes two examples of skulls which are clearly different, it says nothing about the variance in modern human brain shape. It doesn't seem interesting to me unless one were to characterize the variance and describe the ancient skull in terms of the modern distribution.
Re: Modern human brain organization emerged only recently
#3Original article: http://advances.sciencemag.org/content/4/1/eaao5961.full
Re: Modern human brain organization emerged only recently
#4What's interesting that if the basic point is true (that modern human brains emerged only 100,000 - 35,000 years ago) then its amazing (and scary) how quickly things have moved from there. It wasn't that long after "relatively speaking" that the Greeks emerged, then the Romans, Egyptians, Europe, Asia, etc, and now our modern technology driven civilization.
Re: Modern human brain organization emerged only recently
#5How do they reconcile the fact that apparently only brains after 35k years ago show this new brain morphology when humans left Africa at least 70k years ago (when they showed up in Australia).
So one of the groups, either the "in Africa group" or the "out of Africa" group still should have the "old style brains" unless magically the changed happened in both groups at simultaneously. And yet I believe all humans currently alive have essentially similar brains.
Re: Modern human brain organization emerged only recently
#6Note, the original paper is about evolutionary patterns of overall brain shape, which is far from indicating how brain organization evolved. The important parts of brain organization are encoded by patterns of structural and functional connectivity, which are internal to the brain and not well depicted by the overall shape. The paper is great, but the write-up just jumps to some distant conclusions.
Re: Modern human brain organization emerged only recently
#7How do they reconcile the fact that apparently only brains after 35k years ago show this new brain morphology when humans left Africa at least 70k years ago (when they showed up in Australia). So one of the groups, either the "in Africa group" or the "out of Africa" group still should have the "old style brains" unless magically the changed happened in both groups at simultaneously. And yet I believe all humans curre…
It's uncomfortable to consider, but there is strong evidence to suggest that the brains of Australian aboriginal people differ in significant ways from their Caucasian bretheren. One study found the aboriginal visual cortex to be significantly larger than the Caucasian equivalent [0], possibly as an adaption to Australia's (visually) vast open spaces. The same study found the Caucasians had significantly larger parietal lobes and cerebellums - the same structures mentioned in this article. Another study found that Caucasians have significantly larger brains on average compared to those of aboriginals [1].
There's also evidence to suggest that modern humans from India [2] have contributed to the Australian gene pool for millennia (long before the arrival of the British), so more dramatic cranial differences may have already been averaged out.
EDIT: deleted figure mis-remembered from an unrelated study.
[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1261675/ [1] https://www.ncbi.nlm.nih.gov/pubmed/6926391 [2] http://www.pnas.org/content/110/5/1803
Re: Modern human brain organization emerged only recently
#8How do they reconcile the fact that apparently only brains after 35k years ago show this new brain morphology when humans left Africa at least 70k years ago (when they showed up in Australia). So one of the groups, either the "in Africa group" or the "out of Africa" group still should have the "old style brains" unless magically the changed happened in both groups at simultaneously. And yet I believe all humans curre…
"Only fossils younger than 35,000 years show the same globular shape as present-day humans, suggesting that modern brain organization evolved some time between 100,000 and 35,000 years ago."
If humans reached Australia well before 35,000 years ago and lived in isolation there and the evolutionary pressure in Australia differed noticeably from that in the rest of the world, then that narrows the gap. And, and.
Re: Modern human brain organization emerged only recently
#9What is striking is the contrast between how little we understand how the brain actually works, and the bold statements about no difference between men and women brains, everything is nurture/nothing nature, etc. The reality is that we don’t really know. I am dying for science to figure out, but until then I only take claims arguing either way as made up opinions.
Re: Modern human brain organization emerged only recently
#10How do they reconcile the fact that apparently only brains after 35k years ago show this new brain morphology when humans left Africa at least 70k years ago (when they showed up in Australia). So one of the groups, either the "in Africa group" or the "out of Africa" group still should have the "old style brains" unless magically the changed happened in both groups at simultaneously. And yet I believe all humans curre…
There is the interesting hypothesis that the first people to reach Australia were the Denosovans and African peoples came much later. It would explain a lot of interesting observations about the peopling of Australia, not least evidence of there being people in Australia before African peoples had left the Middle East and why you can only find significant Denosovan genetic ancestory on the Australasian side of the Wallace line.