Brain complexity: learning new tasks (Introduction)

by dhw, Saturday, November 18, 2017, 12:58 (2345 days ago) @ David Turell

As these posts are getting longer and longer, I will condense my response to the salient points:

DAVID: Don't you think the brain mechanisms of the past are the same as we see in H. sapiens now? Of course they are. Why should they change as they evolve?

Yes, I think they are the same. We know that nowadays the brain expands and contracts IN RESPONSE to new concepts. Your second article says: "Researchers have long known that brains change in response to learning.” (My bold) We also know that the brain and skull expanded in our hominin/hominid ancestors. It is therefore not unreasonable to suggest that they did so because they were simply too small to cope with the new tasks required of them.

DAVID: I'm simply saying that the brain is surrounded by a roughly one centimeter layer of cerebrospinal fluid. This allows for transient expansion and contraction of the brain as it absorbs new processes. There is no need for Habilis to expand its skull as it learns to throw a spear.

But his skull DID expand. And we know brains expand in response to new concepts. Homo sapiens’ brain and skull no longer expand, because the process of cell selection described in the second article – which we called rewiring before – makes expansion unnecessary (but see below). Once more: if Habilis’s brain had been able to cope, it would not have expanded, and nor would the skull.

DAVID: And note that H. sapiens appears to be 300,000 years old, and even though we have learned all sorts of skills and concepts in that time period, our skulls are now slightly smaller!

Explained above: the rewiring process makes expansion unnecessary, and I have suggested that the transition from brain and skull expansion to rewiring was the result of the brain and skull reaching their optimum size in relation to the rest of the body. But this latest research shows that expansion still occurs initially as the brain copes with new concepts, and it also explains the shrinkage, as the brain selects. As you say, the mechanisms now are basically the same as in the past; new tasks lead to expansion, but now the expansion gives way to rewiring.

DAVID: This does not explain 200cc jumps.

We have no idea how many jumps there were because, as you rightly say, the fossil record is so sparse. But the fact that there are already so many jumps suggests an ongoing repeat of the same process: new concepts, brain expansion, skull expansion as it adapts to accommodate the expanding brain.

DAVID: Why do you not like God in control all the time? Does He need rest?

Why do you want your God controlling every evolutionary change, lifestyle and natural wonder? What is there for him to watch with interest if he does it all himself? And do you never question the likelihood of your God personally dabbling all these changes, or packing a programme for all of them into the first cells, to be passed on through billions of years to every organism that ever existed?