Brain expansion (Evolution)

by dhw, Tuesday, July 21, 2020, 12:47 (25 days ago) @ David Turell

DAVID: Same old idea that a new idea drives complexity and also enlargement to happen/appear. As far as I have presented my arguments, the history of sapiens does not support your view.

dhw: Yes, you have repeated my theory and have offered no reason for rejecting it other than the fact that it is not proven. Meanwhile, I have pointed out umpteen times that the history of sapiens offers us evidence that the brain changes when it implements new requirements (not before it does so), and the process whereby minor enlargements occur within the existing capacity could be taken as an indication that the same process was in operation in former times before the brain stopped expanding and complexification took over. What have you found in the history of sapiens that contradicts my view?

DAVID: I'll repeat your proposal. Older smaller less complex brain thinks of new tool (artifact) concept, but can't produce it until a new larger brain implements the idea. Correct that statement, but that is my interpretation of your theory.

I don't know why you keep trying to rephrase my theory for me, but this is not quite right. Older, smaller, less complex brain thinks of new concept, and the process of implementing the concept causes the same brain to expand.

DAVID: The sapiens history does not support it. Just stasis for 270,000 +/- years after arrival of new brain. Why stasis if a new idea is driving expansion? Implementation should be quick if under your idea of driving the expansion.

The stasis refers to the fact that after the expansion there were NO new ideas that required changes to the brain! Of course implementation of the original brain-changing idea would have been relatively quick: old brain…new idea…brain expands to sapiens size. No more new ideas for 270,000 years. That = stasis. Suddenly there are new ideas, but instead of expanding, the brain implements the new ideas by enhanced complexification. What is your problem?

dhw: Plasticity is what allowed all brains to complexify and early brains to enlarge. I don’t see how your God’s giving his group of homos an overnight injection of an unnecessary 150 cc of brain allowed anything, since whatever was injected minus the 150 ccs would have worked just the same without it.

DAVID: Plasticity did not cause enlargement, just rearrangement of neuron networks. The extra 150 cc allowed us to self-tailor our brains, a very reasonable supposition.

I did not say plasticity CAUSED enlargement! The brain could not expand or complexify without plasticity! What does “self-tailor” mean? Did we use the extra 150 cc or didn’t we? Apparently not, according to you: for 270,000 years there was stasis, and when we came up with our new ideas, the extra 150 cc proved unnecessary and disappeared.


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