Brain complexity: learning new tasks (Introduction)

by dhw, Friday, November 24, 2017, 13:50 (2556 days ago) @ David Turell

DAVID: Using what we know about sapiens, a brain learns something new by slightly enlarging and then shrinks as it reorganizes. No permanent brain enlargement.
dhw: Round we go. There is no permanent enlargement in sapiens because further enlargement would be impractical. That is why reorganization/complexification took over from pre-sapiens enlargement.
DAVID: I proposed that enlargement/shrinkage exists in all pre-homos. You agreed. Remember?

Yes, but that is not the issue. If temporary enlargement and shrinkage (through complexification) could not implement the new concept (e.g. making and learning to use a spear), the effort of implementation would have required new cells, and that would have caused expansion beyond the existing size. I don’t believe expansion took place for no reason and without a cause!

DAVID: What if pre-habilis couldn't envision a spear? Only habilis had the concept and implemented it, all with the same brain. That is the only way to interpret artifacts.

If habilis envisioned the spear and made it without the need for extra cells, then of course he wouldn’t have needed brain expansion. I have simply taken the spear as an example (though I think it’s a good one, as it requires so many new skills). You keep ignoring the fact that brains DID expand and we know from modern scientific research that the brain changes (whether complexifying or enlarging) in response to new tasks, whatever they may be. It doesn’t change in advance of new tasks. Your next answer illustrates my point, except for the vagueness of its language.

dhw: Why would your God bother to expand pre-sapiens brains if there was no progress?
DAVID: Each brain enlargement allowed progress beyond the last stage.

Progress comes in the form of new concepts. But they cannot be made real without brain changes, which happen with the effort to implement new concepts. Hence each brain enlargement RESULTED from the implementation of new concepts. The changes do not happen BEFORE the concept is even formed!

dhw: And so if there was a sudden leap forward 10,000 years ago, it could only have been because certain individual souls or certain individual brain cell communities came up with new ideas.
DAVID: Agreed. All thinking individuals contribute to our progress. We educate each other.
dhw: So that’s settled! Slow progress until a few specially clever individuals caused the leap. Except that you still can’t bear the thought that this is a perfectly natural progression.
DAVID: Of course a perfectly natural progression with no permanent brain enlargement.

Yes, the brain had reached its optimum size. Thank you for accepting my solution to the “mystery” of the sudden leap.

dhw: You agree that sapiens brain and skull could not enlarge any further without serious physical problems. That is why sapiens complexification (with resultant shrinkage) took over from pre-sapiens enlargement.
DAVID: All pre-homos had a degree of complexification! This is why the progression of hominins had a 200cc increase with each new stage of evolutionary development.

The increase didn’t come about because pre-homos had a degree of complexification! It came about when complexification couldn’t cope, and the implementation of new concepts required expansion. THAT is why each new stage of evolutionary development was a progression from complexification to enlargement as new concepts became a reality.

DAVID: God enlarged it for them in 200cc jumps to reach the next stage of human evolution and thought capacity. Your convoluted inverted theory is to avoid God's agency.
dhw: You agree that the brain does not change until it starts to IMPLEMENT new concepts (proven by modern science: learning to write), but now you say your God had to change the brain BEFORE pre-sapiens could think up the concepts whose implementation was what changed the brain! And you offer this contradictory inversion just because you want your God to dabble every branch and stage of the evolutionary bush, and you can’t bear the thought that he might have set up a mechanism whereby organisms work out their own ways of surviving and improving.
DAVID: I'm sorry you cannot accept God at work. But your substitute theistic approach is also God at work.

I cannot accept your pointless inversion of the process whereby implementation of concepts causes brain change, as proven by modern science. But if God exists, then of course my alternative interpretation has him at work. He would have created the mechanism whereby the cell communities of all organisms adjust their structure in order to implement new concepts: the human body for bipedalism, the human brain to translate ideas into reality, the whale to move from land to water, the fish to move from water to land. Every change as a response to challenges and opportunities in a perfectly natural progression which explains the whole history of life on Earth in terms of the common descent you and I both believe in.

(See also under “brain complexity; more important than size”)