Evolution and humans:big brain size and food supply (Evolution)

by David Turell , Thursday, June 22, 2017, 01:37 (2710 days ago) @ dhw

QUOTE: This means the human brain is pre-programmed to be extremely flexible; its cerebral organisation is adjusted by the environment and society in which it is raised. So each new generation’s brain structure can adapt to the new environmental and social challenges without the need to physically evolve. (DAVID's bold)

dhw: Flexible is the same as your own term “plastic”. I don’t know to what extent individual brains are individually wired, but each individual will respond in his/her own way to environmental and social challenges. In the distant past, quite clearly the brain did have to evolve physically, in order to realize new concepts (hence enlargement). Now it densifies, which is another form of physical evolution, so I don’t quite know what is the point of this bold.

It appears the evolution of size of the brain is over. Due to plasticity.

DAVID’s comment: this article has a clear diagram of our hominin ancestors. Each had a bigger frontal lobe. Note my bold about the modern brain's flexibility. He thinks the larger brains resulted from larger social groups. Dhw would agree. And I would state the opposite. The origin of a bigger brain allowed the larger social structures….

dhw: I would not agree. If I adopted your dualistic approach to the source of consciousness, I would argue that new concepts demanded the larger brain for their realization, and these new concepts contributed to the success of the group, which therefore itself grew larger and larger. Concepts first, large brains second, realization of concepts third, large groups fourth.

Again missing the obvious point. To use simple examples: H. habilis made simple tools and lived simply. H. erectus with a larger brain made more complex tools. Your claim is that habilis had concepts that forced enlargement, but the new tools are with erectus! Size first, use second. Your thoughts are totally backwards.

DAVID’s comment: the obvious corollary is if you have a big enough brain to control fire, you can nourish that big brain so it works properly. See my entry yesterday: Tuesday, June 20, 2017, 00:36 . Once again, big brain first, use second.

dhw: But you say our unique cognitive ability is not caused by our large brain, which we/our consciousness use only to give material expression to the results of our deep thinking. You keep restricting the discussion to two stages of "brain and use" without defining use.

You've forgotten I have defined use as survival activities. Tool making, etc.

dhw: If you/your consciousness do not need the brain to do your thinking (as you have agreed), once more the sequence is: 1) concept; 2) big brain; 3)realization of concept (= use of brain).

I don't know how you can describe my use of brain this way. My brain is my gateway to my consciousness. Only the recent development of the H. sapiens brain, starting 350,000 years ago allowed the complexity that required densification. Your sequence is backwards. Our current modern brain is filled with concepts and shrinking. Why isn't it enlarging per your hypothesis?