Brain expansion: different theories about rapid expansion (Evolution)

by dhw, Tuesday, September 15, 2020, 11:32 (1317 days ago) @ David Turell

DAVID: They didn't do nothing. They went on living on the level of sophistication they were born into. Bit by bit new concepts appeared and sapiens developing them at an exponential rate because the capacity of their brain was prepared to do it.

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.

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. My own theory fits in with either scenario, but I cannot identify the specific cause of each expansion. I am also “theorizing, not in specifics”. But at least I am consistent in my theorizing.

DAVID: […] the brains contain a complexification mechanism which is also a reorganization mechanism in small interconnected areas.

dhw: Precisely: a mechanism which complexifies, reorganizes and even adds new cells, and does so without any intervention from your God. So why do you insist that the mechanism could not have complexified, reorganized and added more new cells in earlier brains?

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.

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.

dhw: As for your objection to my own theory, I can only repeat that NOBODY knows what caused the different enlargements. I have suggested “new ideas, ways of life, changes of environment” – and you very kindly suggested a change of climate, though you didn’t mean to.

DAVID: I said the climate was pleasant: "no new advances in life-style in a pleasant climate."

dhw: How do you know what the climate was like 314, 999 years ago, before your God stepped in and performed his operation?

DAVID: I'm quoting experts about why Africa was the birthplace of humans.

I’m not disputing that! Do you think the climate has always remained stable and has always been exactly the same all over the vast continent of Africa? But I’m not even saying that it WAS the climate that presented new requirements – you added it to the above list of possible causes.

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?

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?

xxxxxx

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.

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