Thinking about a quote from HPMOR (the podcast is quite good, if anyone was interested):

But human beings had four times the brain size of a chimpanzee. 20% of a human's metabolic energy went into feeding the brain. Humans were ridiculously smarter than any other species. That sort of thing didn't happen because the environment stepped up the difficulty of its problems a little. Then the organisms would just get a little smarter to solve them. Ending up with that gigantic outsized brain must have taken some sort of runaway evolutionary process, something that would push and push without limits.

And today's scientists had a pretty good guess at what that runaway evolutionary process had been.

...

It really made you appreciate what millions of years of hominids trying to outwit each other - an evolutionary arms race without limit - had led to in the way of increased mental capacity.

Besides the quoted "Chimpanzee Politics" are there any other references to this hypothesis? I've tried Googling around for 5 minutes and I couldn't find anything.

Edit: seems like I was looking using the wrong keywords: Wikipedia seems to have a small paragraph on evolution of human brain due to competitive social behavior, but I'd still like to see if anyone else had any articles on the matter.