I have been reading through this brand-new paper on cooked food. An experiment tested whether great apes have a preference for cooked food. The result showed that there is a statisticially significant relationship with apes choosing cooked food over non-cooked food.
Why is this impotant? A major hypothesis is that humans first utilized fire for warmth, and then much later learned to use fire for cooking. This new research on apes suggests there was already a pre-existing preference for cooked food as humans evolved. This would mean that soon after fire was controlled by humans, cooking became prevalent.
The study shows that apes preferred both cooked meat and cooked vegetables over the non-cooked counterparts. This gives more support to the idea that cooked tubers were an important part of human evolution and the Paleolithic diet. Back in 1999, researchers proposed that cooked tubers played a bigger role than most thought. The new study on apes lends support to their hypothesis.
One small thing I was curious about was how apes would encounter any type of cooked food in the first place. The paper notes that chimpanzees prefer seeds that are heated from wild fires. This means that apes encountered cooked/heated food on a random basis, when fires on the savannah heated existing foods.