Archeology: Did earlier humans posses more brainmatter than Homo Sapiens Sapiens?

[Franz H]

Dear Scienceforums Community,

In this article by Beth Blaxland and Fran Dorey (2018) changes in brain size amongst different human species were measured and compared in cubic centimeters (cc). 

Australopithecus afarensis: 450 cc

Homo habilis: 610 cc

Homo ergaster: 860 cc

Homo heidelbergensis: 1250 cc

Homo sapiens: 1350 cc

 

This makes total sense to me. Yet I chanced apon this article via a link at the end of another article also by Fran Dorey from two years after the first one.

Which stated that ,,Homo sapiens living today have an average brain size of about 1350 cubic centimetres which makes-up 2.2% of our body weight. Early Homo sapiens, however, had slightly larger brains at nearly 1500 cubic centimetres.''.

 

So I came to this forum because I wanted to have an exchange with archeologists about the actual state of science in 2024.

Did brainmass only increase over the course of time or did it actually get reduced in Homo Sapiens Sapiens?

 

 

Blaxland, B. & Dorey, F. (2018). https://australian.museum/learn/science/human-evolution/larger-brains/

Dorey, F. (2020). https://australian.museum/learn/science/human-evolution/homo-sapiens-modern-humans/

[iNow]

I don't know the answer to your archeology focused question, but do wish to highlight that brain size, volume, and amount of matter are hardly as relevant as how that matter gets organized, connected, and folded

[sethoflagos]

Villmoare et al (2022) have yet to see a serious challenge to their summary:

Quote

"We were struck by the implications of a substantial reduction in modern human brain size at roughly 3,000 years ago, during an era of many important innovations and historical events — the appearance of Egypt's New Kingdom, the development of Chinese script, the Trojan War, and the emergence of the Olmec civilization, among many others,” Villmoare said. 

 

“We re-examined the dataset from DeSilva et al. and found that human brain size has not changed in 30,000 years, and probably not in 300,000 years,” Villmoare said. “In fact, based on this dataset, we can identify no reduction in brain size in modern humans over any time-period since the origins of our species.”

 

[Franz H]

18 minutes ago, iNow said:

I don't know the answer to your archeology focused question, but do wish to highlight that brain size, volume, and amount of matter are hardly as relevant as how that matter gets organized, connected, and folded

Thanks for highlighting that. I think relevant is whatever interests the individual. If your maxime is intelligence, then not only brainsize is of importance of course. 

5 minutes ago, sethoflagos said:

Villmoare et al (2022) have yet to see a serious challenge to their summary:

 

Wow thanks that is already very interesting! 

That is a great piece of summary.

Now two questions remain:

What about the brain size of hominids before 300.000 years ago?

And if the brain size of Homo Sapiens Sapiens didn't change, did the internal structures change much? 

[exchemist]

19 minutes ago, Franz H said:

Thanks for highlighting that. I think relevant is whatever interests the individual. If your maxime is intelligence, then not only brainsize is of importance of course. 

Wow thanks that is already very interesting! 

That is a great piece of summary.

Now two questions remain:

What about the brain size of hominids before 300.000 years ago?

And if the brain size of Homo Sapiens Sapiens didn't change, did the internal structures change much? 

How could we know? Brain tissue does not get fossilised sufficiently perfectly. 
 

But there is no reason I am aware of to think early man was any less intelligent than we are today. 

[Franz H]

5 minutes ago, exchemist said:

How could we know? Brain tissue does not get fossilised sufficiently perfectly. 
 

But there is no reason I am aware of to think early man was any less intelligent than we are today. 

Good point. That question might not be answerable... Yet ;P

Then you are a rather progressive thinker I'd say. Many people believe we are now significantly more intelligent than humans before big civilizations or even than humans a few hundred years ago. 

[exchemist]

18 minutes ago, Franz H said:

Good point. That question might not be answerable... Yet 😜

Then you are a rather progressive thinker I'd say. Many people believe we are now significantly more intelligent than humans before big civilizations or even than humans a few hundred years ago. 

Yes. I think some people confuse knowledge with intelligence. Knowledge is a collective possession of humanity that accumulates down the centuries and possibly increases exponentially. But people in earlier times were obviously intelligent. They built the pyramids, calculated the circumference of the Earth and so on. They just had fewer intellectual tools, and less information,  to work with. 

[Franz H]

4 minutes ago, exchemist said:

Yes. I think some people confuse knowledge with intelligence. Knowledge is a collective possession of humanity that accumulates down the centuries and possibly increases exponentially. But people in earlier times were obviously intelligent. They built the pyramids, calculated the circumference of the Earth and so on. They just had fewer intellectual tools, and less information,  to work with. 

 I think so too. We have inhereted the great tool of written knowledge passed on from earlier generations. Also there is the tool of passing on of information verbally still practiced by some other cultures than ours (the western world). That skill is sadly declining further with the decrease in the need to make use of our great memory capacity. 

[sethoflagos]

1 hour ago, Franz H said:

What about the brain size of hominids before 300.000 years ago?

Including Pongo, Pan, Gorilla and forebears?

Just looking at late Homo erectus, adult brain sizes varied between 550 cc and 1250 cc depending on physical size and local environment due in major part to phenotypic plasticity - different populations adapting quickly to highly divergent habitats.

Add to that the extreme rarity of good fossil crania and consequent large statistical uncertainty, you can imagine almost any trend pattern you like. But the data is just too scant and variable to justify it.

[swansont]

1 hour ago, exchemist said:

How could we know? Brain tissue does not get fossilised sufficiently perfectly. 

Brains don’t, but skulls do. So the volume of the brain is discernible if the skull fossil is sufficiently complete. And I think this contains some information.

https://en.m.wikipedia.org/wiki/Endocast

“While an endocast can not directly reveal brain structure,[1] it can allow scientists to gauge the size of areas of the brain situated close to the surface, notably Wernicke's and Broca's areas, responsible for interpreting and producing speech.”

[Franz H]

38 minutes ago, sethoflagos said:

Including Pongo, Pan, Gorilla and forebears?

Just looking at late Homo erectus, adult brain sizes varied between 550 cc and 1250 cc depending on physical size and local environment due in major part to phenotypic plasticity - different populations adapting quickly to highly divergent habitats.

Add to that the extreme rarity of good fossil crania and consequent large statistical uncertainty, you can imagine almost any trend pattern you like. But the data is just too scant and variable to justify it.

Very interessting!

Phenotypic plasticity seems to be the crux here.

Thanks!

 

 

[Ken Fabian]

I haven't looked deeply into this but first impressions... too small sample sizes for one. Mostly I suspect there was a shift upward in population where agriculture and civilisation had taken hold raising the proportion of total human population with lower brain size (as response and possibly adaptation to changed diet and even out of some pre-existing regional genetic variations) whilst everywhere else brains remained much the same as before. Any suggestion the whole human population changed like that, simultaneously around 3,000 years ago lacks a global cause - which would not result in the same genetic outcomes; all turning out the same isn't how evolution works without selection or gene flow. Gene flow within that time to present - Middle East to Europe and Asia, Europe to Americas, Oceania - ought to be largely traceable through DNA, but I don't know that anyone has done those studies.

Edited June 25 by Ken Fabian