Brain complexity: more important than size (Introduction)

by dhw, Wednesday, November 29, 2017, 18:50 (2333 days ago) @ David Turell

dhw: You have already agreed that progress is made through individuals. I do not accept that there was no progress for 290,000 years, but 10,000 years ago there were some particularly bright individuals who came up with concepts that would have caused rapid change (complexification).
DAVID: My answer, sapiens had to learn to use the new capacity. And with complexification the brain and skull shrunk a little.
DAVID: Added: That advance was in the very civilized parts of the world. But there are still parts of the world with isolated indigenous people. We all have the same brain size related to body size. The indigenous have still not learned to use all of it, wich is my point about jump in size and then learning to use it.

You are talking about the brain of homo sapiens, which we assume was the final jump and will probably stay the same size. I don’t suppose any human would claim to have used ALL of its potential, unless you think we’ve finished learning, inventing, discovering etc. But whereas in pre-sapiens days, the existing brains eventually proved too small to cope with what needed to be learned, and therefore expanded, now instead of expanding, they complexify.

dhw: The new, optimum capacity was reached 300,000 years ago. Complexification had to take over, and was so efficient that the brain no longer needs quite as many cells as it had before.
DAVID: Complexification involved more than cells. Connectivity with much more branching of axons is equally important.

I thought an axon was part of a neuron, and I thought a neuron was a cell. Ah well, in that case, the brain shrank because complexification was so efficient that it didn’t need to be as big as it was.

dhw: […]300,000 years ago complexification took over from jumps. What’s the problem?
DAVID: Artifacts! What a brain can think of is evidence of the present concepts and the implementation it is capable of at its current size.

Once again: today the implementation only takes place at the brain’s current size, because it can’t expand any more. But in pre-sapiens days it could and did expand, and as we know from modern science, it is the process of implementation that changes the brain. In pre-sapiens days, the production of the artefacts required a new capacity, so the change was expansion, whereas today the implementation of the concept requires rewiring. The changes do not take place BEFORE the concept, and they are CAUSED by its implementation.

dhw: Do you or do you not accept the findings of modern science that the brain changes in response to concepts, and not in anticipation of them?
DAVID: Once a new brain size is established, the new advanced level of hominin learns to use it. Each level responds by complexification at the same size. The brain change is within a given size as demonstrated by current science. You can't extrapolate otherwise.

Yet again you avoid giving a direct answer. The brain change is within a given size NOW! But yes, once a size was established, the hominin brain would also have complexified within that given size until the size was no longer adequate to implement the concept. Then it expanded. If you agree that the brain changes in RESPONSE to concepts and efforts to implement them, as proven by modern science, and not beforehand, then it makes no sense to claim that in the past the brain changed BEFORE the hominin had the concepts and tried to implement them. That would be like saying that today the Indian women’s brains rewired before they learned to write.