Insights: Cooking Up Bigger Brains; January 2008; Scientific American Magazine; by Rachael Moeller Gorman; 3 Page(s)

Richard Wrangham has tasted chimp food, and he doesn't like it. "The typical fruit is very unpleasant," the Harvard University biological anthropologist says of the hard, strangely shaped fruits endemic to the chimp diet, some of which look like cherries, others like cocktail sausages. "Fibrous, quite bitter. Not a tremendous amount of sugar. Some make your stomach heave." After a few tastings in western Uganda, where he works part of the year on his 20-year-old project studying wild chimpanzees, Wrangham came to the conclusion that no human could survive long on such a diet. Besides the unpalatable taste, our weak jaws, tiny teeth and small guts would never be able to chomp and process enough calories from the fruits to support our large bodies.

Then, one cool fall evening in 1997, while gazing into his fireplace in Cambridge, Mass., and contemplating a completely different question--"What stimulated human evolution?"--he remembered the chimp food. "I realized what a ridiculously large difference cooking would make," Wrangham says. Cooking could have made the fibrous fruits, along with the tubers and tough, raw meat that chimps also eat, much more easily digestible, he thought--they could be consumed quickly and digested with less energy. This innovation could have enabled our chimplike ancestors' gut size to shrink over evolutionary time; the energy that would have gone to support a larger gut might have instead sparked the evolution of our bigger-brained, larger=bodied, humanlike forebears.