From this story on Wired Science:
Stone toolmakers living in southern Africa 75,000 years ago pushed the cutting edge in more ways than one. These intrepid folk sharpened the thin tips of heated stone spearheads using a forceful technique previously dated to no more than 20,000 years ago, a new study finds. This stone toolmaking method, called pressure flaking, was invented and used sporadically in Africa before spreading to other continents, according to a team led by archaeologist Vincent Mourre of the University of Toulouse-Le Mirail in France. Having a flexible repertoire of toolmaking methods aided the survival of modern humans who left Africa beginning around 60,000 years ago, the scientists propose in the Oct. 29 Science.
_The finding fits with the idea that symbolic art, rituals and other forms of modern human behavior developed gradually over hundreds of thousands of years, not in a burst of cultural innovation marked by cave paintings and other creations that appeared after 50,000 years ago in Western Europe. Excavations of sediment dated to 75,000 years ago in South Africa's Blombos Cave produced stone artifacts displaying signs of pressure flaking, Mourre and his colleagues say. "The Blombos evidence for pressure flaking is the oldest we know," says anthropologist and study coauthor Paola Villa of the University of Colorado Museum of Natural History in Boulder.