Origin of modern behavior?
WASHINGTON They lived 77,000 years ago in a cliff-side cave overlooking what is now the Indian Ocean. They made flaked tools and bone points, and engraved a polished stone with a crosshatched pattern of triangles evidence, perhaps, of an ancient flight of fancy.
The artifacts from South Africa's Blombos Cave and the behavior they suggest have added fuel to one of anthropology's most contentious debates: When and where did anatomically modern humans start acting in a cognitively "modern" way?
For years, the prevailing view held that humankind's first flowering occurred somewhat suddenly about 40,000 years ago in Eurasia, with the development of shaped bone tools and other sophisticated crafts that culminated in the spectacular cave paintings in Western Europe that dazzle the artists' descendants even today.
But Blombos Cave strengthens an alternative hypothesis: that modern behavior began much earlier in Africa. Recent advances in genetics have demonstrated that anatomically modern humans came "out of Africa" about 100,000 years ago and spread northward. Blombos indicates that modern behavior may have evolved concurrently and spread the same way.
"We can now say that Europe is not the center of modern human behavior," said Christopher Henshilwood, a paleoanthropologist at the State University of New York at Stony Brook and an associate at the Iziko-South African Museum in Cape Town. "It's in Africa."
In excavations since 1992, Henshilwood has led a multinational team that has produced evidence of what he said are "people who had the ability to exploit their environment" to develop a "really broad-based" fishing and hunting economy "associated with modern behavior."
Last week in Science Express, the online version of the journal Science, the team described two pieces of red ocher iron ore that had been ground flat on one side and engraved in a crosshatched pattern of overlapping triangles. The team tested surrounding cave material using several different techniques and fixed the age of the fragments at 77,000 years.
Since the design is a geometric pattern apparently unrelated to any natural phenomenon, Henshilwood asserted that the fragments show that the Blombos people were "capable of abstract thought, and of expressing it in engravings." Such behavior, regarded by scholars as clearly "modern," didn't appear in Europe until much later, he added.
"This is absolutely stunning,". said George Washington University anthropology professor Alison Brooks. "It shows modern cultural capabilities and implies that the capability is always there in Africa."
Stanford University professor Richard G. Klein, however, questioned the authenticity of some Blombos artifacts and the interpretation given to the red ocher, noting that even Neanderthals, the European precursors of modern humans, produced marked stones and modern-looking tools and bone "every once in a while."
He also contrasted southern Africa, with only a few artifacts in a smattering of sites, to what he called the "cultural big bang" that began in Eurasia about 45,000 years ago: "People start fishing, populations begin to grow and the more capable people displace anyone who's in their way.
"My own view is you have to look for a pattern. The first instance is an accident. The second is coincidence. When you have three or more, you start to get a pattern. This doesn't happen here."
Henshilwood argued, however, that the evidence of widespread modern behavior in southern Africa simply needs to be found: "In Africa there are probably only 10 or 12 sites that have been well-excavated," Henshilwood said. "If we look at France or Spain, there are literally hundreds and hundreds."
Another skeptic, Harvard University professor Ofer Bar-Yossef, said more digging probably won't help, but offered a compromise interpretation of the Blombos find: that while the Africans were perhaps every bit as sophisticated as the Henshilwood team claims, no one else followed their lead.
"They lived in isolation in a world with few people, where what they did either wasn't accepted or wasn't noticed, and then they went extinct," Bar-Yossef said.
Brooks also acknowledged that "at a certain point in time" the Blombos people may have needed innovative technology, "but later they didn't" need it or simply no longer had it "for whatever reason." Such cultural blind alleys frequently occur in history, she noted.
MODERN CAVE LIFE Bone points and bifacially worked stone (left) from South Africa's Blombos cave (right), which was inhabited 77,000 years ago. WASHINGTON POST PHOTOS