Brain expansion: different theories about rapid expansion (Evolution)

by David Turell , Tuesday, September 15, 2020, 14:46 (1528 days ago) @ dhw

dhw: If they went on living in the manner they were born into, there was stasis, which for some reason is your main point. But hey presto, now you’re saying that bit by bit new concepts appeared. Please tell us what these new concepts were, prior to the sudden burst of new ideas (and apparently a slight reshaping of the brain) approx. 35,000 years ago. […]

DAVID: I am theorizing, not in specifics. I think the advent of serviceable language certainly helped started the explosion of thought and information 35,000 years ago.

dhw: You said stasis was your main point. I keep asking why your God would have operated on the Moroccans 280,000 years before they needed their new brain. Now you theorize that there wasn’t stasis. Please make up your mind.

You asked about new concepts, not stasis and I answered accordingly. Of course stasis.

DAVID: There was God's intervention. He designed the system. As for expansion of 200 cc of non-descript neurons with potential but no current function, tell me your natural driving force, because I don't see one except God.

dhw: You have not answered my question (now bolded). My theory allows for God designing the system, which you keep agreeing functions WITHOUT God’s intervention! The natural driving force for expansion is NEW REQUIREMENTS (e.g. new ideas, ways of living, environmental changes) which the existing sized brain cannot meet without additional cells. Now please answer my question.

And I answer stasis does not present new requirements as the Moroccans. New uses 35,000 years ago shrunk the brain! Your theory is inconsistent with fact.

DAVID: Of course God did it. That is my position. All brains, pre-sapiens and sapiens had the complexification mechanism given by God. The required complexity of design requires God's designing mind.

dhw: This is amazing. With my theist hat on, that is also my position! ALL brains, pre-sapiens and sapiens, had the same complexification mechanism, and since the modern brain also adds cells when needed, I see no reason why the same mechanism (which changes the brain in response to new requirements) should not have done the same. […]

DAVID: Drifting verbiage. Did God do it or didn't He as you wander along your picket fence?

dhw: I have offered you a theory to explain brain expansion. My theory is based on what we know about the workings of the modern brain. It allows for the existence of your God. You have confirmed everything I have presented, and the only answer you can give me now is that I must make up my mind whether to be an agnostic or a theist. May I take it that you have now given up trying to find flaws in my theory, and we can close this long discussion?

We can end it in full disagreement. Stasis in the Moroccans disproves hour theory.

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Under “glial cells”

QUOTE: "'To a large extent, the general architecture and wiring of the brain is accomplished by birth," he says. "But it really requires this robust feedback from the environment to continue that maturation." As an animal interacts with its surroundings, some neuronal connections are eliminated while others are strengthened, he explains. It's a process that, in humans, continues for decades after birth.

“Interaction with surroundings” is the key. The brain REACTS to new requirements, it does not change in anticipation of them. And I would suggest it is a process that extends to the whole of evolution, but on a wider scale. All cells change their structure to meet new requirements or exploit new conditions.

DAVID: this means the complexification mechanism is actually under immune control and involves synapse pruning. How some areas thicken is related to regions of the hippocampus adding neurons as in London cabbies memorizing London. In humans adding neurons is very limited to this region.

dhw: But the very fact that the brain is capable of adding neurons makes it feasible that earlier brains could have done the same.

Your narrow view keeps ignoring the hippocampus, a center for memory which does add neurons to a small degree as we age and add memories. For you that means an entire brain can make 200 cc enlargements in evolution.