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Saturday, May 03, 2008

Fred on everything, including evolution: Hot air about big brains

Columnist Fred Reed offers a send-up of speculative theories about the evolution of large brains in humans, “Circling the Paradigm: Protecting the Theory at Any Cost” (April 21, 2008):
A standard theory among a large school of evolutionists is that intelligence is low among people in sub-Saharan Africa, where humanity apparently originated, because life in tropical climates doesn't impose great intellectual demands; when people migrated to colder climates, as for example in Europe, they had to evolve higher intelligence to survive. To most people it seems obvious that higher intelligence would be useful anywhere at all, so why, they ask, didn't it arise below the Sahara?

Hart replies that larger brains carry not only benefits but also costs and, by implication, that in some places the costs are greater than the advantages. The costs of larger brains are, he says:

1) Larger brains require larger amounts of energy.

2) Larger brains require larger heads, which create strains on the muscular and skeletal structure.

3) Larger brains (and larger heads) require wider female pelvises and the wider pelvises result in less efficiency in walking and running."
This is evolutionary boilerplate, and also absurd. The two are often seen keeping company.

I won’t even try to keep up with Fred in debunking the “big brains” nonsense, but here is an interesting fact: Size of brain does not necessarily correlate with intelligence in humans. See these Mindful Hack stories, for example:

How much brain does a man really need? Not much.

Also: How much brain do you need? Could you use that space for something else?

While we are here, it is worth noting that some creatures, like whales, have much bigger brains than humans, but have not used them to develop thinking faculties similar to humans.

My own view is that when people believe in mechanistic theories, they tend to reach for them as an alternative to other theories, whether they are useful or not. Where they are not useful, they spin them out a little more, as in Fred’s hilarious examples. Here is more of Fred on Everything.

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