It's become widely accepted that a major (if not primary) force behind the development of big, complex brains in humans was the development of controlled fires for cooking. Cooked food is food that's been digested a little for us -- breaking down proteins and fibers means more calories and more nutrients with less work.
But what if this view is wrong? Controlled fire may only date to around 400,000 years ago, much too late to produce our big brains.
To try to pin down the earliest evidence of controlled fire use, Paola Villa at the University of Colorado in Boulder, and Wil Roebroeks at Leiden University in the Netherlands re-examined the data from over 100 European sites. They were looking for evidence of fires that were unlikely to have occurred naturally - those in caves, for example - and for clues that fire had been used in a controlled way. These include activities such as making pitch: some early hominins made this sticky substance by burning birch bark and using it to glue pieces of flint to wooden handles to make stone tools easier to use.
The earliest European hearths date back between 300 and 400,000 years, the researchers conclude - much later than existing theories suggest. Some archaeologists think that controlled fire use dates back 1.6 million years. Richard Wrangham of Harvard University has even suggested that hominins began using fire 1.9 million years ago, leading to a cooking tradition that made digestion easier and freed up the extra energy our ancestors needed to grow bigger brains. ...
"The European evidence strongly suggests that the habitual and controlled use of fire was a late phenomenon," Villa and Roebroeks conclude. The findings controversially suggest that people migrated from Africa to the below-freezing winter temperatures of Europe without fire. These early hominins might have combined a high-protein diet with a highly active lifestyle to survive, the researchers speculate.
Source: New Scientist
This new evidence is interesting, but definitely not conclusive. One important argument against the conclusion that controlled fire came so late is the idea that whenever humans started using fire to cook, it surely would have produced significant effects in our biology -- but we don't see any major changes around 400,000 years ago.
So either fire and cooked food is far less interesting than we think (which is possible, but seems unlikely) or cooking food must have started earlier than the best evidence from Europe says so far. But if that's the case, why don't we have any evidence of that?
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