I happen to be sitting down to a late lunch now of primarily raw food — sushi and fruit. Bad for the brain?

The evolution of human intelligence, compared to our ape-like predecessors, is one of those niggling Darwinian enigmas that won’t go away. Intelligence is far more than simply a function of brain size, but the gist of a bunch of science coverage that’s out today suggests that we got to be as smart as we are because of our big brains, which in turn are explained by a technological innovation: cooked food.
This was all sparked by an article in Proceedings of the National Academy of Sciences (“Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution“). Apes, you see, don’t get enough calories from their raw diets to grow brains as big as ours. Homo erectus receives the credit for turning things around by coming up with the idea of roasting meat and veggies. A co-author of the PNAS study, neuroscientist Suzana Herculano-Houzel, explained to reporter Ann Gibbons for Science.

To Herculano-Houzel’s mind, our brains would still be the size of an ape’s if H. erectus hadn’t played with fire: “Gorillas are stuck with this limitation of how much they can eat in a day; orangutans are stuck there; H. erectus would be stuck there if they had not invented cooking,” she says. “The more I think about it, the more I bow to my kitchen. It’s the reason we are here.”

The reason we’re here?
Citing the advent of cooking to explain how we got here takes you about as far as trying to account for the development of manned space flight from primitive examples of powered flight with reference solely to the development of modern liquid rocket propellants. There would be no question of flying to the moon without appropriate fuel, but obviously there’s a lot more to it — the transition from the Wright Brothers to Neil Armstrong — than that.
The food, like the fuel, is necessary but hardly sufficient. Without the engineering, the fuel takes you nowhere at all.