That one is called the Machiavellian intelligence hypothesis - and it is covered in The Runaway Brain - and by Robin Dunbar in his "The Social Brain Hypothesis".

There are some other noteworthy ideas in the space as well - for instance the idea that omega-3 fats represented a nutritional constraint that got lifted by dietary changes. That hypothesis is laid out in The Driving Force.

No doubt all of these ideas have something to them - but the "memes did it" hypothesis is the one that gets my gold star these days.