Brain complexity: learning new tasks (Introduction)

by dhw, Monday, November 20, 2017, 13:58 (2347 days ago) @ David Turell

dhw: At least you seem now to have accepted that the brain expands/rewires IN RESPONSE to new concepts and tasks, which does away with the whole idea that your God expanded it before hominins, hominids and homos came up with their new concepts.
DAVID: Once I found the studies, I've always understood that the brain expands to handle new activities and then contacts as the new networks are reorganized. And you have accepted the probability that this mechanism probably goes back to pre-homo times. Skull size thus is constant.

Skull size is constant NOW, but you keep pointing out that brains and skulls expanded by saltations in pre-homo times. What you have recently told us (thank you for all the research you relay to us) is that the sapiens brain expands and then rewires and contracts within the skull as a result of new tasks to be performed. The same process probably took place in the brains of our ancient pre-sapiens forebears, but when rewiring couldn’t cope with any more new tasks, the brain required MORE cells. And so instead of your now discarded hypothesis that God expanded their brains and skulls in ANTICIPATION of new tasks, the brain RESPONDED to the need to fulfil new tasks by expanding, and the skull expanded to house the expanding brain.

DAVID: You keep forgetting, if you don't know what you don't know and at the habilis state they only needed survival skills, how much need is present? I repeat the point for which I haven't found your answer: Sapiens brain is 300,000 years old and smaller now than before. We are filled with an exponential growth of ideas and concepts that encompass graduate schools of education to teach or understand them. Where is your 'required expansion'?

It is the new information/concept/task (i.e. what was not known previously) that requires changes in the brain. Even with your previous hypothesis, the brain DID expand, which implies there WAS a need (remember expansion and rewiring are responses to new tasks). We just don’t know enough about the thoughts of habilis and other pre-sapiens to know what other “needs” (e.g. social) they may have had, but I don’t think it’s unreasonable to suppose that eventually the brain reached the point at which further expansion would have damaged the balance of the body. And so from then on the “exponential growth of ideas and concepts” results in (not is caused by) increased rewiring, i.e. initial mini-expansion (mirroring the evolutionary process that led to the present one) followed by a return to the “normal” size as the brain implements the new task by new complexification. Shrinkage simply indicates the efficacy of the rewiring process. The last article you posted equated this with natural selection, as the brain discards cells that are no longer needed. So once more the sequence would be: ancient brains and skulls expanded when presumed rewiring couldn’t cope with the influx of new ideas. Expansion beyond current size would have proved impractical for the body. No more expansion now (beyond the mini-scale which soon shrinks back), but only complexification. All in a perfectly logical sequence.