Recent excavations and analysis of the molars of Homo erectus and Homo sapiens neanderthalensis suggest that human ancestors began cooking much earlier than originally thought. The introduction of culturally treating food (specifically cooking) directly correlates to smaller molar size in human beings (as thick enamel and wide chewing surfaces are no longer necessary).
Paleoanthropologists have suggested that the the decreasing size of molars in proto-humans suggests that our ancestors were cooking as early as two million years ago. The finding, however, is not without controversy as the connection with cooking also suggest other sophisticated tool use – specifically the control of fire.
“There isn’t a lot of good evidence for fire. That’s kind of controversial,” Organ said. “That’s one of the holes in this cooking hypothesis. If those species right then were cooking you should find evidence for hearths and fire pits.” (MSNBC)
These new findings were published in the Proceedings of the National Academy of Sciences. If you do not have a subscription to this esteemed article, you can read more about it in this article of Scientific American or at MSNBC.