We’re too sophisticated nowadays to laugh at chimps riding tricycles or smoking pipes, right? Well, maybe not entirely, judging by the three million people who've watched a chimp riding a Segway scooter.
The humanlike antics are hilarious because chimps seem so uncannily like us, yet so different. But it keeps getting harder to say exactly how they’re different. Among many, many other chimp skills, primatologists have learned that our closest evolutionary cousins fashion spears to hunt for prey, trade food for sex, play with dolls and don’t take kindly to drones invading their space.
The latest discovery: Chimps have all the cognitive abilities necessary for the uniquely human behavior of cooking. They don’t do it in the wild because they’ve never learned to control fire. But aside from that, according to a study published Tuesday in the journal Proceedings of the Royal Academy B, chimps' brains are pretty much fully equipped to take the great culinary leap our direct human ancestors did in the dim past.
“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. (Learn more about the first kitchens of human ancestors in Africa.)
The archaeological evidence for cooking, however, dates back only about a million years—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.
The mental processes involved in cooking are far too complex to be tested in a single experiment, says Alexandra Rosati, a Harvard evolutionary biologist and co-author of the new study. “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.”
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.’”
Another impressive finding, given that chimpanzees aren’t the most patient of creatures, is that they’ll choose not to eat a chunk of raw potato immediately, deferring gratification for the time it takes to “cook” the food. And in a related experiment, the scientists showed that chimps will carry raw food across a room to the chef rather than cramming it in their mouths right away. Resisting temptation isn’t easy for us; it’s nearly impossible for chimpanzees.
“I am as impressed at the authors' ingenuity in devising these experiments and carrying them out so convincingly as I am at the results,” Wrangham says. Yale psychologist Laurie Santos, an expert on animal cognition, appears equally impressed. “I really like this study,” she says, “and I think it's neat that chimpanzees may have cognitive precursors to cooking even though they don't cook themselves.”
So we can now scratch one more item off the list of abilities that are uniquely human—and strongly resist the urge to put a chimp in an apron make him a contestant on Top Chef.