Much debate surrounds the issue of when and where language, religion, symbolic decorations and other facets of modern human behavior originated. Researchers such as Henshilwood hypothesize that modern human behavior developed gradually in Africa, beginning more than 100,000 years ago. Others posit that a brain-boosting genetic mutation around 50,000 years ago fostered modern behavior in Africa. Some researchers suspect that behavioral advances first appeared in Europe, Asia and Africa at that later time. Possible examples of symbolic behavior from around 100,000 years ago?—?such as proposed human burials in the Middle East and pigment use in Africa?—?have been controversial.
“What makes the Blombos engravings different is that some of them appear to represent a deliberate will to produce a complex abstract design,” Henshilwood says. “We have not before seen well-dated and unambiguous traces of this kind of behavior at 100,000 years ago.”