Brain expansion (Evolution)

by David Turell , Wednesday, August 05, 2020, 20:32 (1569 days ago) @ dhw

DAVID: You've changed emphasis […] …artifact or not, what you wrote was an important new idea that had to be implemented so it caused an enlargement to occur for the actual implementation.

dhw: Correct. What I originally wrote was: “pre-sapiens brains expanded when the capacity was too small to meet new requirements (e.g. the implementation and usage of new means of survival). The expanded brain would suffice for so many thousands of years until it could no longer cope with more advances, and so it expanded again.” What part of my theory has changed?

It still interprets as small brain with big new idea needs bigger brain to implement. Which
bigger brained fossil should be accompanied by new advanced artifact. The Moroccan sapiens were not but we see stasis.

dhw: As for the Moroccans, yet again: we don’t know what caused the expansion, but whatever the cause, once again there was a long period when there were no further new ideas or experiences or changes in conditions that required any major change in the brain. This is entirely consistent with my theory.

DAVID: No it isn't. Your theory requires a new event activity (style of life) or article to appear with them. It doesn't.

dhw: NOBODY KNOWS the causes of each expansion, so do you expect me to give you a list of what requirements led to which expansion?

Your underlying theory requires a new artifact to appear with the new larger brained fossil.

DAVID: If your idea is true under the deluge of ideas we sapiens have had our brain should have expanded, but complexification made it shrink.

dhw: You said that with my theory the brain should have carried on expanding. I say it couldn’t for anatomical reasons, and so complexification took over. We are not talking about elephant intelligence or what concept is important, but about the reasons for expansion and sapiens non-expansion and use of enhanced complexification.

you brought up elephant heads, I didn't

Under “Big brain evolution”:

QUOTES: "But the wait pays off for larger-brained primates: They're eventually able to perform more complex tasks with their hands, like using tools, or moving both hands simultaneously to move multiple objects.”

"'It is no coincidence that we humans are so good at using our hands and using tools, our large brains made it possible," Heldstab said. "A big brain equals great dexterity."

dhw: Leaving aside dualism versus materialism, the question for us is why the brain expanded in the first place, and the above article combined with “Revisiting language and brain expansion” offers us insight into the whole process.

Yes.

QUOTE: "To account for the development of this skill, some scientists have hypothesized that parts of the brain that originally evolved for other purposes have been "recycled" for reading. As one example, they suggest that a part of the visual system that is specialized to perform object recognition has been repurposed […](David’s bold)

DAVID: This finding is a logical extension of what we have learned about our big and formally oversized brain. We have been given a brain that has the ability to repurpose or recycle an area with underlying abilities […]

dhw: For once, we agree. This hypothesis illustrates the point that a new requirement leads to brain change. I don’t think even you would propose that your God altered the visual system BEFORE people thought of reading and writing. (The relevant sections of the illiterate women’s brains complexified when they learned to read, and not before). However, since the system did not lose its original function, I’d say it complexified (perhaps even expanded), not that it was repurposed or recycled. In young apes and humans, both brains go through all the past stages, starting with the simplest of tasks and complexifying as they learn new skills. The young ape brain stops complexifying and expanding at the point at which apes stopped inventing and learning new skills. The young human brain continues to complexify and expand, because it has more new skills to learn. As the authors point out, this process requires time. I wonder if early homo children’s brains reached maturity earlier than those of sapiens children. We shall never know. But what we do know, and what is supported by the above hypothesis, is that the brain changes as it responds to new requirements and not in anticipation of them. I can only repeat that I see no reason why anyone should assume that the same process was not responsible for complexifications and expansions before and including that of sapiens.

No matter what you propose about brain enlargement, all we know is our big brain was present long before it was used in any new way. And it obviously came with a very functional complexification mechanism, causing the brain later to shrink. The whole process appears designed in advance of needs and to handle needs as required over time.