The Machiavellian Intelligence hypothesis says that the brain evolved more for its social purpose, than for finding food and things like that. Incidentally, Google’s collection on evolution is as comprehensive as ever.
Machiavellian Intelligence
The Machiavellian Intelligence hypothesis posits that primate brains evolved primarily to handle complex social interactions rather than for foraging or tool use. This theory suggests social competition and cooperation drove the development of higher cognitive functions.