Brain expansion (Evolution)

by David Turell , Thursday, July 30, 2020, 22:35 (1575 days ago) @ dhw

DAVID: Sapiens in Morocco appeared 315,000 years ago with NO NEW changes in their lifestyle or artifacts. 50-70,000 years ago language started to appear. Caves were still used until much later. All stasis, no invention of the great idea you propose caused it!!! No evidence of anything new.

dhw: Whatever the “great idea” may have been, it would have PRECEDED the expansion, which was caused by IMPLEMENTATION. Stasis FOLLOWED the expansion until new ideas required changes to the brain, as below.
You keep talking as if the Moroccan sapiens meant an overnight change from pre-sapiens to sapiens. This has always seemed absurd to me. The whole human evolutionary process is shrouded in mystery, and the five Moroccans do not solve it, as this article shows:

World’s oldest Homo sapiens fossils found in Morocco ...
https://www.sciencemag.org/news/2017/06/world-s-oldest-homo-sapiens.

The team doesn’t propose that the Jebel Irhoud people were directly ancestral to all the rest of us. Rather, they suggest that these ancient humans were part of a large, interbreeding population that spread across Africa when the Sahara was green about 300,000 to 330,000 years ago; they later evolved as a group toward modern humans. “H. sapiens evolution happened on a continental scale,” Gunz says.

Support for that picture comes from the tools that Hublin’s team discovered. They include hundreds of stone flakes that had been hammered repeatedly to sharpen them and two cores—the lumps of stone from which the blades were flaked off—characteristic of the Middle Stone Age (MSA). Some researchers thought that archaic humans such as H. heidelbergensis invented these tools. But the new dates suggest that this kind of toolkit, found at sites across Africa, may be a hallmark of H. sapiens.[/i]

(dhw: Then maybe one factor in sapiens' brain expansion really was new tools. There is certainly nothing here to damage my theory.)

The finds will help scientists make sense of a handful of tantalizing and poorly dated skulls from across Africa, each with its own combination of modern and primitive traits. […].
The connections among these skulls and the appearance of MSA tools across Africa at this time and possibly earlier shows “a lot of communication across the continent,” Brooks says. “This shows a pan-African phenomenon, with people expanding and contracting across the continent for a long time."

None of this tells us when the MSA tools first appeared and certainly doesn't tell us that pre-sapiens had the first thought of it which then drove the expansion.

dhw: No sudden leap from nowhere. As regards stasis, please explain why, in your own theory, your God stepped in one night 315,000 years ago to give some Moroccans bigger brains (with unnecessary 150 cc), skulls and pelvises, only for them and their descendants to do nothing with them for the next 270,000 years.

God gave us the big brain, from which stasis shows we took time to learn how to use it.

dhw: You wrote: “your changed theory is consistent…” What change? And NOBODY knows what caused the expansion, but new artefacts might have been a factor.

We do not know the length of time the Moroccan sapiens had been around, when the artifacts were made of or thought of. I agree artifacts are a factor

DAVID (re shrinkage): Your assumption that the extra neurons were never used, is not my theory. My point is that many of them were used in the plastic reorganization of our brain to fit our new uses and needs. […]

dhw: […] I really don’t know why you think the whole brain had to be reorganized. In what way? Do you think the cerebellum became the cerebrum, or what? I would assume that all the different areas remained the same, but some of them simply discarded cells that were no longer needed. Too simple for you?

DAVID: I don't know where to begin. The folded cortex of the forebrain did lots of changing as we learned to think with it. Language, as it developed required Broca's area to complexify. [Followed by more examples of how new requirements changed the relevant sections of the brain.]

dhw: My point was that the brain itself was not reorganized. I asked: do you think the cerebellum became the cerebrum. The different sections remained the same, but every new activity required new complexifications, some of which resulted in the superfluity of certain cells, which were discarded. None of this flannel about them being “used in the plastic reorganization of our brain to fit our new uses and needs”. Your list confirms that the brain changes IN RESPONSE to new requirements, and my theory is still that the same process would have applied to earlier brains, whether the changes were complexifications or expansions.

You can reject the 'flannel' as I reject yours, but I described obvious reorganization that had to occur with new uses. You bolded comment was silliness.