New research in South Africa has indicated that early homo were cooking carbohydrate-rich rhizomes about 170,000 years ago:
“[C]ircumstantial evidence for cooking is compelling. The spatial context of the rhizomes in ash rather than adjacent sediment is significant. Further support for cooking comes from amylase gene analysis results, which indicate that a high starch diet, possibly involving processing and/or cooking of carbohydrate-rich geophytes by early humans, was already in place by the Middle Pleistocene. Cooking enables dietary diversity, and transporting geophytes to a home base like Border Cave facilitates both food processing and sharing …
“The Border Cave discovery is early evidence of cooked starchy plant food. The wide distribution of Hypoxis, particularly the small, palatable Hypoxis angustifolia rhizome that grows gregariously in many habitats, implies that it could have provided a reliable, familiar staple food source for early humans moving within or out of Africa.”
This is additional evidence for the hypothesis that cooking made us human (or at least played a significant role in our societal development).