Brain complexity: memory formation (Introduction)

by dhw, Thursday, August 29, 2019, 10:19 (1703 days ago) @ David Turell

dhw: My point was that if learning changes the structure of the brain, clearly the learning precedes the changes, which is why I suggest that the whole history of brain structure, including expansion, just like that of other organs, has come about through the cells’ responses to new situations, conditions etc. This proposal is in contrast to Darwin’s random mutations and to your own theory that your God made all the changes (either by preprogramming or by dabbling) before the new situations etc. arose.

DAVID: The changes we know in Indian illiterates and London cabbies alters an existing brain but does not create a species with a new brain size and capacity. I think your theory is a real stretch.

If you accept common descent, you will have to accept that the new brain size and capacity were the result of changes to existing brains. Since we know that learning changes the structure of the brain, it is not unreasonable to suggest that once an existing brain had reached the limits of its ability to cope with new situations (learning always involves something new to the learner), it had to increase its capacity. This too means a structural change – more cells, more connections, and an expansion of the container to house the new cells. I can’t see that this is more of a “stretch” than random mutations, or your God popping in to do a dabble before there is any need for expansion (just as you think he popped in to change the pre-whale’s legs into flippers before it entered the water). It seems perfectly logical to me that if something new causes existing structures to change now, it may have done the same throughout evolution.