“The Great Leap Forward is probably one of the most hotly contested aspects of evolutionary genetics. It’s a mystery, really. We know that around fifty to sixty thousand years ago, there was a sort of ‘Big Bang’ in human intelligence. We got a lot smarter, very quickly. We just don’t know exactly how. We believe it was some kind of change in brain wiring. For the first time, humans began using complex language, creating art, making more advanced tools, solving problems—”
