From the Christian Science Monitor:
Around 50,000 years ago, something happened to our ancestors in Africa. Anatomically modern humans, who had existed for at least 150,000 years prior, suddenly began behaving differently. Until then, their conduct scarcely differed from that of their hominid cousins, the Neanderthals. Both buried their dead; both used stone tools; and as social apes, both had some form of communication, which some think was gestural.
But then, "almost overnight, everything changes very rapidly," says Merritt Ruhlen, a lecturer in the Anthropological Sciences Department at Stanford University in Palo Alto, Calif. Humans began making much better stone tools. They started burying their dead with accouterments that suggested religion. And perhaps most telling, Homo sapiens, the "wise" apes, began creating art.
"People started having imagination at this time much more than they had earlier," says Dr. Ruhlen.