It's an interesting piece of natural history and discussion. It talks about some of the things that made smartness possible, including big brains and roaming around. However it doesn't seem to address the question of what actually made us smart.
My answer would be: our genes, and later on our culture too, began to optimise for meme transmission and storage. This process snowballed and we went further down that route than any other species.
My answer would be: our genes, and later on our culture too, began to optimise for meme transmission and storage. This process snowballed and we went further down that route than any other species.