Wednesday, February 22, 2012

did cooking make you human?

We are the only species on earth that cooks its food and we are also the cleverest species on the planet. The question is: do we cook because we're clever and imaginative, or are we clever and imaginative because our ancestors discovered cooking? Horizon examines the evidence that our ancestors' changing diet and their mastery of fire prompted anatomical and neurological changes that resulted in taking us out of the trees and into the kitchen. The question is do we cook because we are clever and imaginative, or are we clever and imaginative because our ancestors discovered cooking?

Homo Habilis had a bigger brain (50% bigger) than his forebear, Australopithecus. Was this down to his diet? In Did Cooking Make Us Human?, a clutch of determined scientists set out to discover the extent to which diet played a role in the evolution of the human brain, using a variety of mildly alarming gadgets. Professor Peter Ungar has a contraption he calls the Bitemaster Two, a mechanical chewing machine he has fitted out with genuine Australopithecine gnashers. For the first time in three million years they were set to work on a carrot with success. On raw meat they performed less well, unlike the teeth from a later human ancestor.

Australopithecines didn't eat animals, skulls with fang holes show that it was the other way round. At some point in our evolutionary history it's clear that we developed a taste for animal flesh, but it's not altogether obvious when, or why. Hunting is tricky, risky, time consuming and exhausting, and there is little evidence that Homo habilis, for example, was any good at it. In search of answers Professor Travis Pickering went to meet Namibian Bushmen to get a feel for the hunter gatherer lifestyle. Although it's not glamorous work it takes the Bushmen four hours in 40 degree heat to dig a porcupine out of its hole they left one in no doubt as to its importance. "I don't particularly like eating porcupine," said one of the Bushmen shyly "but meat is meat."

The programme's most interesting contention was that cooking led directly to our bigger human brains. "Cooking is huge," said Professor Richard Rangham. "I think it's the biggest increase in the quality of diet in the whole of the history of life." No one is sure when our ancestors first became chefs estimates range from two million to 800,000 years ago and the fossil record hasn't been much help so far. They've found charred animal bones (evidence of hunting prey with fire) and butchered animal bones (evidence of meat eating) but no charred and butchered bones yet. The advantages of a cooked diet are, from an evolutionary point of view, you absorb more calories while expending less energy, and can make do with a smaller, less elaborate gut.