Modern human brain organization emerged only recently • Hacker News Board

Re: Modern human brain organization emerged only recently

#11

Post by lobf » Tue, Jan 30, 2018, 9:03 AM UTC

astebbin wrote: post #7

sunstone wrote: post #5

How 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 parie…

Isn't gene expression dependent on environment though? Is there some reason to believe that these differences are inherent, and not the result of gene expression being affected by the environment?

Re: Modern human brain organization emerged only recently

#12

Post by danieltillett » Tue, Jan 30, 2018, 9:03 AM UTC

nrau wrote: post #4

What'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.

Speed of evolutionary change is basically proportional to the population size. Thanks to the huge increase in population size after the rise of agriculture, more human evolution has happened in the last 5000 years than the previous 500,000.

Re: Modern human brain organization emerged only recently

#13

Post by WillReplyfFood » Tue, Jan 30, 2018, 9:04 AM UTC

nrau wrote: post #4

What'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.

I really wonder about the relations between the earlier hominides and the brainiacs.

Re: Modern human brain organization emerged only recently

#14

Post by Karnickel » Tue, Jan 30, 2018, 9:09 AM UTC

cm2187 wrote: post #9

What 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.

> the bold statements about no difference between men and women brains, everything is nurture/nothing nature, etc.

You are attacking a position that is not the common scientist position at all. Your whole comment is a bit surprising given the context. You went out of your way to invent a reason to vent.

"Study finds some significant differences in brains of men and women": http://www.sciencemag.org/news/2017/04/study-finds-some-sign...

https://stanmed.stanford.edu/2017spring/how-mens-and-womens-...

https://www.psychologytoday.com/blog/hope-relationships/2014...

It does not even matter how accurate any of those articles are, this just serves to show that the claim made by OP is wrong. There are plenty of science articles about differences.

So what exactly is the basis for your claim again? Did you do any research of your position at all (and just googling quickly before posting already counts)? It seems to be entirely made up.

> made up opinion

Such as yours? :-)

Re: Modern human brain organization emerged only recently

#15

Post by astebbin » Tue, Jan 30, 2018, 9:25 AM UTC

lobf wrote: post #11

astebbin wrote: post #7

Earlier quoted context omitted.

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 parie…

Isn't gene expression dependent on environment though? Is there some reason to believe that these differences are inherent, and not the result of gene expression being affected by the environment?

IANA biologist. That said, if by "inherent" you mean primarily genetically determined, I'd say that explanation seems most likely given the evidence.

Re: Modern human brain organization emerged only recently

#16

Post by TheAdamAndChe » Tue, Jan 30, 2018, 9:40 AM UTC

lobf wrote: post #11

astebbin wrote: post #7

Earlier quoted context omitted.

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 parie…

Isn't gene expression dependent on environment though? Is there some reason to believe that these differences are inherent, and not the result of gene expression being affected by the environment?

> Is there some reason to believe that these differences are inherent, and not the result of gene expression being affected by the environment?

That is a question that remains to be answered, and is only just beginning to be looked into through research on epigenetics[1].

[1] https://en.wikipedia.org/wiki/Epigenetics

Re: Modern human brain organization emerged only recently

#17

Post by TheAdamAndChe » Tue, Jan 30, 2018, 9:44 AM UTC

danieltillett wrote: post #12

nrau wrote: post #4

What'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.

Speed of evolutionary change is basically proportional to the population size. Thanks to the huge increase in population size after the rise of agriculture, more human evolution has happened in the last 5000 years than the previous 500,000.

Really? I thought selective pressure was required to cause a major shift in the average human. The reason that our population has boomed is because our selective pressure has declined significantly. Or are you more talking about the adaptability of the species overall has increased?

Re: Modern human brain organization emerged only recently

#18

Post by cm2187 » Tue, Jan 30, 2018, 10:05 AM UTC

Karnickel wrote: post #14

cm2187 wrote: post #9

What 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.

> the bold statements about no difference between men and women brains, everything is nurture/nothing nature, etc. You are attacking a position that is not the common scientist position at all. Your whole comment is a bit surprising given the context. You went out of your way to invent a reason to vent. "Study finds some significant differences in brains of men and women": http://www.sciencemag.org/news/2017/04/study…

Talking about making up your own invented antagonistic positions: I am not arguing everyone else pretends there are no difference, I am arguing that some do. Quoting some articles arguing that there are differences doesn't prove anything. As for the ad hominem arguments,...

Re: Modern human brain organization emerged only recently

#19

Post by ZeroGravitas » Tue, Jan 30, 2018, 10:05 AM UTC

danieltillett wrote: post #10

sunstone wrote: post #5

How 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 Wa…

Your use of "African" seems confusing here. In particular the line "evidence of there being people in Australia before African peoples had left the Middle East" seems to suggest you think Denosovan people didn't originate in Africa.

Re: Modern human brain organization emerged only recently

#20

Post by perl4ever » Tue, Jan 30, 2018, 10:06 AM UTC

TheAdamAndChe wrote: post #17

danieltillett wrote: post #12

Earlier quoted context omitted.

Speed of evolutionary change is basically proportional to the population size. Thanks to the huge increase in population size after the rise of agriculture, more human evolution has happened in the last 5000 years than the previous 500,000.

Really? I thought selective pressure was required to cause a major shift in the average human. The reason that our population has boomed is because our selective pressure has declined significantly. Or are you more talking about the adaptability of the species overall has increased?

In a booming population, it seems to me that evolution can be more rapid in "selection" with less "pressure". For instance, if humans start exploring a new continent, some might have 10 times the normal number of grandchildren, and their genes would rapidly outnumber the others. Whereas if population is static, then you could say there's more "pressure" but there's probably less "selection", because there's less opportunity and variance in success.