Friday, October 29, 2004

Evolving brains

A new study tracks the development of brains – in cetaceans. There was one jump in brain size about 35 million years ago, which may correspond with the development of echolocation. After that, brain sizes started to vary all over the place. Some of the cetaceans may have brains comparable to ours.

"Here you have four or five different animal groups that, from an evolutionary standpoint, are very different," says Marino. "But there’s clearly a higher order selection effect that has created similarities in function. It might be the consequence of some aspect of social interaction." "And keep in mind," Marino points out, "brains don’t all just get bigger over time. You’d better have a very good reason for having a big brain, because they’re metabolically very expensive. You’ll have the brain that you need, no more." But for those creatures inhabiting an ecological niche where intelligence pays off, it sounds as if high IQ’s could be reached via many roads. "Cetaceans and primates are not closely related at all, but both have similar behavior capacities and large brains -- the largest on the planet. Cognitive convergence seems to be the bottom line."

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