Big brain evolution: brain size and intelligence (Evolution)

by David Turell @, Sunday, April 15, 2018, 18:57 (930 days ago) @ dhw

dhw: Of course in life they function together, but the dualist s/s/c’s immaterial thoughts and concepts precede implementation and therefore do not depend on the size of the brain. As you say, that is “obvious dualism”.

DAVID: Modern science studies an already established human brain of very large prefrontal and frontal cortical size, and doesn't tell us, in any way, how it arrived at that end point.

dhw: Agreed.That is why there are different hypotheses.

DAVID: Thus only a larger brain with an expanded thought area (prefrontal cortex) allows for the development of highly complex concepts, as proven by the artifacts at each level of brain complexity in earlier hominin fossils.

dhw: The artefacts are the material implementation of the immaterial thoughts. If you wish to argue that the pfc PRODUCES the concepts/thoughts, you are once again embracing materialism, which may be correct but is not what you profess to believe.

DAVID: You know full well that the s/s/c uses the pfc to produce concepts and thoughts during life.

dhw: No I don’t. As above, if I were a dualist and believed that a conscious, thinking s/s/c survived the death of the pfc, the “obvious dualism” would be that the s/s/c was responsible for producing concepts and thoughts during life, and used the pfc and the rest of the brain to provide information and – as you keep agreeing – to implement its thoughts. I remain on the fence between dualism and materialism.

DAVID: If our most previous ancestors had 'immaterial thoughts' that required expansion (your 'push' concept) why was there a delay of 305,000 years for those thoughts to appear and be implemented?
dhw: Our immediate ancestors did not think the thoughts we thought ten thousand years ago! They thought the thoughts that caused the final expansion.
DAVID: The bold is your 'push enlargement' hypothesis stated as fact. While all we know is shrinkage in size of the human brain, while its use is vastly increased, which you admit…

dhw: All we know is not shrinkage. We know that the modern brain responds to new concepts by complexifying and by partially expanding within the given limits of the skull (and I suggest that shrinkage is merely a by-product of efficient complexification).

Not true. Shrinkage is a major effect of modern thought/concepts appearing as I have previously presented:

" Over the past 20,000 years, the average volume of the human male brain has decreased from 1,500 cubic centimeters to 1,350 cc, losing a chunk the size of a tennis ball. The female brain has shrunk by about the same proportion. “I’d call that major downsizing in an evolutionary eyeblink,” he says. “This happened in China, Europe, Africa—everywhere we look.'”


"The Homo sapiens with the biggest brains lived 20,000 to 30,000 years ago in Europe. Called the Cro-Magnons, they had barrel chests and huge, jutting jaws with enormous teeth. Consequently, their large brains have often been attributed to brawniness rather than brilliance. In support of that claim, one widely cited study found that the ratio of brain volume to body mass—commonly referred to as the encephalization quotient, or EQ—was the same for Cro-Magnons as it is for us. On that basis, Stringer says, our ancestors were presumed to have the same raw cognitive horsepower."

Comment: As we developed complex modern thinking our brains are much smaller.

dhw: My hypothesis is that early brains expanded when existing brains did not have the capacity to implement new concepts. We don’t know what concepts would have triggered expansion, but new ideas for artefacts are one possibility.

Doesn't fit the discussion in the article.

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