If you give a chimp an oven, he or she will learn to cook.
Alexandra Rosati, an evolutionary biologist at Yale and a co-author of the study that could help explain how and when early humans first began cooking their food, published in the Proceedings of the Royal Society B that: “This suggests that as soon as fire was controlled, cooking could have ramped up”.
“It requires patience, future-oriented cognition—it’s tied up in how animals make decisions about time and value,” she says. “We thought it was a really interesting and kind of wacky project to pursue.”
Rosati and Felix Warneken, a psychologist at Harvard University, carried out the study at a chimpanzee sanctuary in the Democratic Republic of the Congo. First, the researchers gave the chimps a device that appeared to work like an oven.
The device was actually just a bowl with a false bottom that held cooked food. The researchers didn’t use fire because it could have ɪɴᴊᴜʀᴇd the chimps, and because some chimps might have already seen how humans used it to cook food.
“You can think of it as a chimpanzee microwave where, basically, if the chimpanzees placed raw food in the device and then we shook the device, [the food] came out cooked,” says Rosati, who will be moving from Yale to Harvard this summer.
In the end, Rosati and co-author Felix Warneken, a Harvard psychologist, did nine separate experiments to assess different aspects of cooking-related thinking. For example, they confirmed that, offered the choice, chimps prefer cooked vegetables over raw, as earlier research had shown. They also showed that chimps comprehend that cooking is a process—that food is transformed into a tastier form when it goes into an oven for a few minutes. (In this case the ‘oven’ was a container with cooked food hidden in a secret compartment; researchers shook the container to signal to chimps that some process transformed raw vegetables into cooked forms.)
Not all of the animals got it immediately. Rosita remembers a large adult male named Maya who liked cooked veggies well enough, but didn’t quite comprehend the “cooking” process. Finally, she says, the chimp cautiously put some raw food into the container, almost as if he was thinking “well, I’ll just go for it.” When Warneken started shaking the container, she says, “Maya got really excited. He started vocalizing and practically jumping up and down. You could practically see the light bulb turn on in his head with the insight that his food was now being ‘cooked.’”
“I love it,” says Harvard evolutionary biologist Richard Wrangham, who has long argued that the transition to from raw to cooked food spurred a dramatic increase in the brain capacity of human ancestors nearly two million years ago, leading to the emergence of our ancestor, Homo erectus.
The idea is that cooked meat and vegetables are far easier to digest than the raw versions, thus providing more available calories for our energy-hungry grey matter.
Evidence suggests early humans learned to control fire between 400,000 and 2 million years ago —long after the human brain’s great leap forward—so this new study would be a boost for Wrangham’s idea. If chimps had most of the mental equipment in place to make cooking possible, early humans presumably would have had it too.