Monday, January 12, 2009

Pinker genes

Posted by Danny Tarlow
I liked this article by Steven Pinker about our genome and our psychology: He even goes into different interpretations of probability on the last page. But the most interesting point to me was the argument that personality traits seem to be controlled by a small number of genes because a wide variety of variations are likely to be useful:
The optimal personality may also depend on the opportunities and risks presented by different environments. The early bird gets the worm, but the second mouse gets the cheese. An environment that has worms in some parts but mousetraps in others could select for a mixture of go-getters and nervous nellies.
Intelligence, on the other hand, seems to be controlled by a large number of genes:
There aren’t many mutations that can make us a whole lot smarter. Mutations in general are far more likely to be harmful than helpful, and the large, helpful ones were low-hanging fruit that were picked long ago in our evolutionary history and entrenched in the species. One reason for this can be explained with an analogy inspired by the mathematician Ronald Fisher. A large twist of a focusing knob has some chance of bringing a microscope into better focus when it is far from the best setting. But as the barrel gets closer to the target, smaller and smaller tweaks are needed to bring any further improvement.
Regardless, the big picture point is that we have a long way to go before we can get much definitive information from our genomes.

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