Evolution and humans: big brain size uses energy (Evolution)

by dhw, Monday, October 23, 2017, 13:46 (30 days ago) @ dhw

QUOTES: "'On an acute level, we have now demonstrated that when humans simultaneously experience extremes of physical and mental exertion, our internal trade-off preserves cognitive function as the body's priority."
"He points to examples of this trade-off in humans benefiting the brain. "The selfish nature of the brain has been observed in the unique preservation of brain mass as bodies waste away in people suffering from long-term malnutrition or starvation, as well as in children born with growth restriction.'"

dhw: David, perhaps you could explain to me how they know that, for example, a starving gorilla’s cognitive functions disappear before its body wastes away. The question should be particularly interesting for any dualist.
I’d be grateful for an answer to this question, if you happen to know.

DAVID: I don't know of any studies of starving apes, but in the human condition, concentration camp survivors weighing 80 pounds fully preserved their thinking capacity.
Think of Viktor Frankl's book. I would think apes have the same preservation mechanism.

Thank you. I suspect that all dying organisms with brains would have the same mechanism: i.e. their cognitive faculties would be the last to go (other than with such diseases as dementia). So I really don’t know why the researchers single out humans, as if they knew humans were special in this particular context.

dhw:It doesn’t matter when the changes began. You have no way of knowing that they were not in response to local changes in the environment. I don’t understand the reference to “loss of muscle before the brain growth”. I suggest that early hominins underwent anatomical changes, including those to the brain, after and as a result of their descent from the trees (whereas you tell us your God preprogrammed or dabbled them BEFORE they descended). How can we know the sequence?
DAVID: The fossils demonstrate loss of muscle while the brains are still small and they are bipedal. There is an obvious sequence. Environmental response does not affect the sequence I point out.

I can’t comment on this until you explain to me what muscles early hominins actually lost and when they lost them. If you’re thinking of 23 million years ago, it may well be that the adjustment did not require any development of the brain. Clearly your God didn't think it did, since you're telling us he did NOT expand their brain before they descended!

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