Oldowan stone-knapping dates back to the Lower Paleolithic period in eastern Africa, and remained largely unchanged for 700,000 years until more sophisticated Acheulean hand-axes and cleavers, which marked the next generation of stone tool technology, came on the scene. It was practiced by some of our earliest ancestors, such as Homo habilis and the even older Australopithecus garhi, who walked on two legs, but whose facial features and brain size were closer to those of apes. In testing five different ways to convey Oldowan stone-knapping skills to more than 180 college students, the researchers found that the demonstration that used...