Brain complexity: learning new tasks (Introduction)

by dhw, Thursday, November 23, 2017, 14:09 (2557 days ago) @ David Turell

dhw: … if the concept of learning to write CAUSED the brain to change in the course of implementation, it is illogical to assume that the brain had to change before habilis had the concept of making tools.
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.

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: Whew! Pre-habilis says I can envision throwing a spear but I need a bigger brain to figure it out. Poof! "My brain is exploding" and now I am a habilis!

Not to figure it out! To implement it! Once again: If the brain changes now (complexification) through implementation of new concepts (e.g. learning to write), it would also have changed then (enlargement) through implementation of new concepts (learning how to make the spear figured out beforehand.)

dhw: What point are you trying to make with regard to each hominin advance in brain size?
DAVID: Hunter-gatherers (as sapiens) have very simple survival skills and do not use their brains as we do. Hominins were little different. There was not much brain needed to be used. Social interaction is in small groups of 30-50 individuals more or less. Hardly any degree of complexity.

I can’t follow your reasoning. Are you now saying each enlargement was without any purpose since pre-sapiens and early sapiens didn’t make much progress? I would say spears represent progress over bare-handed hunting – enough to cause brain expansion. Why would your God bother to expand pre-sapiens brains if there was no progress?

dhw: You keep harping on about 300,000 years and 290,000 years. The exact figures are not known, but bigger-brained Neanderthals are believed to been around 200,000 years ago, and interbred with sapiens. They are now considered to have been very sophisticated, so how “minimal” is minimal advancement up to 10,000 years go?
DAVID: Neanderthal 'sophistication' compared to what? Made jewelry, buried dead, wore hides , lived in caves.

Apart from “lived in caves”, which doesn’t require any new concept, you now have the birth of aesthetics, perhaps the birth of ritual, and a wide array of skills involved in hunting and tailoring.

DAVID: Before the final Neanderthals died out, our sapiens were drawing pictures in caves (starting about 40,000 years ago), but no further advanced at that time. Neanderthal brains were bigger but obviously less complex.The 300,000 years is something you are meticulously avoiding. Our big brain appeared back then, but mostly unused until 10,000 years ago. Why so big if it is driven by concepts of pre-sapiens who can't implement them, but supposedly thought of them before the size appeared? It took 290,000 years to learn how to use our big brain.

300,000 years or so ago the brain reached the size beyond which expansion would have been impractical. Whatever NEW concepts then came to mind would have been implemented by complexification. I don’t buy your downgrading of jewelry, burial, clothing as insignificant, and drawing pictures 40,000 years ago is an amazing use of the brain, so it is absurd to say we didn’t use it until 10,000 years ago. But I accept that there was a leap forward.

dhw So please give us your theory as to why, according to you, sapiens didn’t use his brain capacity for 290,000 years.
DAVID: Had to learn how to use it.

I suggest he was using it all the time, and I have offered you an explanation of the leap:
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.

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: Lucy had concepts. Very simple ones. Sapiens have very complex ones, using a much more complex brain. Concepts change the brain. But sapiens never enlarge their skull. In fact over 300,000 years it is slightly smaller. Therefore neither did habilis or erectus using the same enlargement/shrinkage technique.

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: 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.

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.