I once heard a very interesting theory that suggested that a lot of human development could be attributed to the discovery of cooking.
The theory went like this. Human beings have been able to advance above all other species mentally. This had allowed them to develop tools and societies and form a more complicated social order than any other species on earth. This is a result of biological factors like the size of our brains but cultural factors as well.
Once humans discovered how to cook, to make plants soft and meat more edible, they could spend so much less time looking for the food they needed to survive. Think about a cow. It pretty much has to eat grass all day long in order to get its fill. If it could eat a big pot of cooked grass or a loaf of grass bread it could consume more nutrition more quickly.
Once humans freed themselves from the burden of foraging for raw food they could begin to develop more complicated social orders, experiment with tools and agriculture and focus on all the advances that allowed us to rise above other animals. I'm not sure if this makes total sense, but it is an interesting theory.