Keen On

So why do we humans have such big brains? According to the NYU neuroscientist Nikolay Kukushkin, it’s because of language. In wanting to talk to one another, Kukushkin argues in his new book, One Hand Clapping, we need to be able to think more coherently than other species. Thus our uniquely big brains. Language itself emerged from our increasingly social lifestyle, Kukushkin explains, which developed after our mammalian ancestors spent 150 million years hiding from dinosaurs in what he calls the "nocturnal bottleneck." And what good have our big brains done us? That, according to Kukushkin, is a trickier question. It’s certainly made us more social, even collective, in our politics and culture. But it also seems to have divided us from one another, fostering as much misery and violence as harmony. Indeed, Kukushkin suggests that we've always been "grumpy"—even back when we lived in caves. The difference now is that we have the internet to advertise our grumpiness. More seriously, though, we're the first spec