It might seem obvious why chimps don’t have tea parties; they’d make a massive mess for a start, but the ability to cook food requires surprisingly advanced mental skills. You need to be able to understand that taking the food and processing it will produce something different and, more importantly, wait while this happens. New research, published in the Proceedings of the Royal Society B, suggests that chimps already possess these intellectual abilities.

In a series of experiments on wild-born chimpanzees, researchers have demonstrated that the animals “in principle, have the critical cognitive capacities for cooking,” according to Felix Warneken from Harvard University, who co-authored the study. “If our closest evolutionary relative possesses these skills, it suggests that once early humans were able to use and control fire they could also use it for cooking.”

It’s been shown that many animals prefer cooked food over raw as it is softer and hence easier to digest. But the scientists wanted to take this one step further by first examining whether chimps could wait until raw sweet potato was cooked, and then see if they truly grasped the transformation of the snacks by having them place raw food in a “cooking device”—actually a bowl with a false bottom—to get cooked food back.

A lot of this was about delayed gratification. The chimp can either eat the raw potato instantly or put it in the “oven” and wait a few minutes to get a tastier, more nutritious food back. They found that the chimps were quickly able to understand that the device “cooked” the food, and were prepared to wait for it to happen.

“People focus on the control of fire because that seems so salient, but even if you had a fire stick, several other insights are required before you can use it for cooking,” Alexandra Rosati, one of the authors of the study, said. “Obviously, chimps can’t control fire, but we were trying to hypothesize about some of the other aspects of cooking, like the causal understanding that if you put this raw food on the fire it creates cooked food, or, at the extreme end of our study, the ability to plan.”

They examined the chimps' ability to plan by firstly providing the chimps with multiple pieces of raw food but also giving them the opportunity to wait for researchers to cook and provide them with the same amount of cooked food, and secondly by seeing if the chimps would carry the raw potato from one side of the enclosure to the other in order to be cooked. This last test, say the researchers, was particularly difficult for the apes.

“They'd often try to carry it with their mouth, because chimpanzees are knuckle walkers, and you'd almost see them accidentally eat the food on their way over, almost like 'oops' they couldn't even resist, because they were carrying the food in their mouth,” Rosati told Scientific American.

The assumption is that early man controlled fire and then used it cook, but the researchers suggest that this might actually have happened in reverse: cooking gave people a reason to control fire.