20 October 2009

Neurosci Lesson #1: Be Humble

EconLog | Arnold Kling | A Proposal for Masonomics Fieldwork

A comment on my last post on political dispositions:
The real reason people with high IQs lack common sense is neurological. You can't be cerebral without sacrificing cunning. It takes real live brain matter to support each. Unless you've got a second brain hidden somewhere, you can't get around this tradeoff. The extreme form of this can be seen in the autistic brain. While autism is just a behavioral profile at present, the brains of high-functioning autistic people have been studied enough to reveal a pattern of early abnormal overgrowth in areas implicated in the things autistic people do well: art, music, mathematics, etc. The price they pay is a corresponding undergrowth of the white matter linking the neocortex to the rest of the brain. (There are other abnormalities as well.) The neocortex is responsible for executive function, working memory, and generalization, among other things. Generalization is how we acquire biases. Autistic people are bad at this. That means they lack prejudice, which is what we call the biases we don't like. The ones we like, we call common sense. If you want to get some idea of what the world would look like if we overcame bias, go to a group home for autistic adults.
Emphasis added. [...] Given that both neuroscience and autism are both controversial fields, my guess is that there people who would dispute the commenter's generalizations.
Well I would dispute the neuroscience there.

In the comments to this post, the author of the above comment says that the brain must be subject to some trade-offs between abilities.
The tradeoff probably isn't just between the two traits I named. But I'd bet my life that no great mathematician ever had the "situational awareness" to be an NFL quarterback or ace fighter pilot.
That may be true, but it is also easily explainable if "intelligence" and "situational awareness" are completely independent. How many of the world's great artists have been over seven feet tall? Probably none. That doesn't mean there's some direct trade-off between artistic talent and height, just that you don't find many examples on the extreme tails of two different, non-positively correlated probability distributions.

He's right that some trade-offs exist in the brain, but I think he's leaping to conclusions that they affect general cognitive abilities like "intelligence" and "cunning" in certain ways. I know some neuroscience, and if there's one thing I've learned it's that we should be very, very humble when discussing the neural correlates of human behavior. We have a pretty decent understanding of how rudimentary perception works, but everything beyond that is more mystery than not.

We don't even understand how we remember things, and we certainly don't understand something as difficult to pin down as "common sense."

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