Big brain evolution: changes in sapiens skull shape (Evolution)

by David Turell @, Saturday, January 27, 2018, 00:51 (1009 days ago) @ dhw

Dhw: Once more, the logic is as follows (some of this may sound familiar to you): homimim has an immaterial idea for spears. NO BRAIN CHANGE. As he learns to knapp flint, attach the stone to a wooden rod, throw it with accuracy etc., his brain enlarges with all the muscle movement and coordination involved, so that by the time he is able to perform all these new actions, his brain has expanded to its new size.

DAVID: No way! His brain added complexity just like ours does. Fits the history of evolution.

dhw: It would have added complexity until it could no longer cope... Your hypothesis leaves you with the same contradiction you simply cannot resolve: you say your God expands the brain, and only then can the hominin think of something new, although thought according to you does NOT depend on the brain.

Must I repeat! The s/s/c uses a more complex cortex for more complex thought, just as your use of Windows 5 cannot accomplish what you can do with Windows 10. Brain does operate without s/s/c running the show.

DAVID: Our brains reached their volume/size about 300,000 years ago, and changed from a more oblong shape to a more globular form by the last 40,000 years, as use of the brain altered its lobes:

Precisely: use of the brain means implementation of concepts (which according to you are the product of the soul), and that is what alters the size, the complexity, and now apparently the shape. Thank you.

QUOTE: "In a study published Wednesday in Science Advances, researchers from the Max Planck Institute for Evolutionary Anthropology announced that the earliest Homo sapiens did not have globular brains like we have today. Instead, their brains had a shape intermediate between that of Homo erectus and that of the Neanderthals, both of which were somewhat more elongated horizontally. The brain, the authors write, gradually became globular over evolutionary time, and those changes in turn, induced neurological shifts that coincide with archaeological evidence of modern behavior. (David’s bold)

DAVID’s comment: My bold supports the theory that artifacts show behaviors the brain is capable of producing. As the brain molded itself into slightly new shapes due to lobe developments with new applications and implementations, the skull adapted to the new spatial requirements. The obvious implication is that as the new species of H. sapiens received its new-sized larger brain, it had to spend time learning to use it creating the newer shape. Size first, use second could not be clearer.

dhw: As for your bold, I agree that changes COINCIDE with the archaeological evidence. That does not mean the changes preceded the archaeological evidence. The illiterate women’s rewiring coincided with their learning to read and write – because the latter was its cause. And so modern behaviour CAUSES neurological shifts. You even say yourself that the brain molded itself “with new applications and implementations” and you also have the skull adapting itself to the new spatial requirements. New applications and implementations change the brain. The brain does not change beforehand.

We don't know your declarative sentences I've bolded are at all true. All your hypothesis.

dhw: The nub of the problem is that you keep conflating two separate stages of my hypothesis: 1) The new sapiens size resulted from the implementation of a new concept conceived by the pre-sapiens “soul”, as vividly described in the first section of this post. 2) From then on, the brain could not expand any further, so yes indeed, the new sapiens size preceded all the new concepts that followed, as conceived by the dualistic soul, but implementation took place through complexification, which apparently also caused reshaping as well as shrinkage. So each pre-sapiens expansion resulted from new concepts that exceeded current capacity; from sapiens onwards, new concepts resulted in complexification with shrinkage and reshaping.

You've agreed above that presapiens brain could have compllexified during implementation, now you have withdrawn it. My point is the same stage of brain development gets the concept and does the implementation. The next larger stage develops the concept and implementation, which is the only way the artifacts fit the fossil history. Size first, use second.

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