Revisiting language and brain expansion (Evolution)

by dhw, Monday, February 03, 2020, 12:54 (240 days ago) @ David Turell

dhw: I propose that our earliest ancestors came up with ideas or were faced with new conditions that required more brain capacity than they already had. We know for a fact (though you prefer to forget it) that implementation of new ideas leads to changes in the brain (the illiterate women, taxi drivers, musicians etc.).(David’s bold)

DAVID: You forget I just mentioned that fact in a recent post. [dhw: Yesterday, in response to my mention of it.] And the modern brain has shown overall shrinking, remember.

So the brain responds to new requirements, and does not change in anticipation of them. I explained shrinkage in my post: [the brain] “eventually shrunk, presumably because complexification proved so efficient”. What is your explanation? Did God pop down and say, “Hey, they didn’t need all the capacity I gave ‘em, so I’ll shrink ‘em”?

dhw: […] let’s say some clever clogs got fed up with having to wrestle a bison in order to get some meat, and thought of putting together a sharp piece of stone, a stick, and one of his arms. But this idea required thoughts and deeds never done before, and just as muscles grow with exercise, so the brain expanded with the effort of planning and producing and throwing the first spear.

DAVID: The biology of muscles allows them to expand to meet the requirements of more work, built in. The brain, a totally biologically different structure with massive use has shrunk. Your comparison does not hold water; it is like comparing oysters to cows.

The analogy is that muscles and brains consist of cells, and cells respond to requirements and use. I’ve explained shrinkage above.

dhw: Take it from there. The brain expands. And for a while, the expanded brain can cope with all the demands made on it…until someone else produces - or new conditions demand - new ideas it can no longer cope with. More expansion.

DAVID: This description is totally Darwinian, since it implies bit by bit growth as new needs appear. It totally ignores the 200 cc jumps in size the fossil record exhibits. And how homo lives improves after each jump, as archaeologists show. This is the key issue you constantly evade.

You quote me and ignore what you quote! I did not say the brain expands with each new need. “The brain expands”(= the jump). “And for a while, the expanded brain can cope with all the demands made on it….” until it can no longer cope. Cue for more expansion (= the next jump).

dhw: To our knowledge, every adaptation that has ever happened has been in RESPONSE and not in anticipation. (David’s bold […]

DAVID: The brain working now is at the end of evolution. It is fully done expanding, based on the shrinkage. The idea that the early brains grew to this size under requirement pressures is totally ass backwards, an inverted Darwinian theory.

What “inversion”? The jumps are progressive as new requirements eventually require greater capacity. I made the point that expansion was over (“the brain expands to a point at which further expansion would unbalance the whole structure, and that is when complexification takes over.”) Why is this so hard to understand? Shrinkage explained above.

DAVID: Your bold is discussing minor needed adaptations within species. The brain expansion IS major speciation, and you mix up the two concepts. You cannot make species adaptation into speciation.

We do not know the extent to which adaptation leads to speciation, but expansion and complexification are not innovations, and the human brain was not a new organ! Unique though it is in its complexities, it started out virtually the same size as the chimp brain. Dogs’ noses are far more complex than ours, but would you call their noses an innovation? However, NOBODY knows how speciation takes place. All the above is theoretical, as is your proposal that an unknown, eternal mind preprogrammed or dabbled every change before it was required.

DAVID (Under “Introducing the brain”): […] this applies to our discussion about which came first large brain or from dhw a necessity telling the brain to enlarge and complexify. The dhw approach demands to know how did the brain learn to make itself function better by enlarging and complexifying?

I propose: In the same manner that ALL evolutionary innovations and adaptations stem from the intelligence, sentience, cooperation, communication and decision-making of cell communities responding to the requirements or opportunities offered by changing conditions. I’m surprised that you have forgotten this theory.

DAVID: Only a designer could have created that mechanism, a mechanism dhw awards to evolving organisms by his suggesting God gave such a mechanism so they could do it themselves.

And why do you consider that to be an argument against the proposed mechanism?

DAVID: In evolution doesn't the present build from the past? We know local brain areas enlarge, when required (London cabbies, illiterate women). Why a limited capacity now?

Thank you for acknowledging that changes in the brain are responses to requirements. And yes, evolution builds from the past.The human brain built on the brain of its primate predecessors. That is precisely the process I have described. Limited capacity because we'd have had trouble with an elephant-sized head, and so complexification took over, as explained above (including shrinkage).


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