The very modern human traits of complex and abstract thinking may have evolved in Africa 77,000 years ago -- almost twice as early as previously believed -- according to a team of anthropologists who unearthed intricate geometric carvings on bits of rock from a South African cave.
The finding, if verified, could overturn much current thinking in anthropology. But the sweeping claim is already generating controversy among anthropologists.
The new discovery suggests that modern human behavior evolved in Africa rather than Europe. And the artifacts -- pieces of red rock etched with geometric shapes -- are more than 40,000 years older than another milepost of complex behavior -- the dazzling paintings of animals and humans -- on the walls of French caves.
"In light of this new evidence it seems that, at least in Southern Africa, Homo sapiens was behaviorally modern about 77,000 years ago," wrote Christopher S. Henshilwood, the anthropologist who led the research. His findings are being published online Friday in the journal Science. The etchings, he said, "may have been constructed with symbolic intent."
Anthropologists consider the production of art, particularly the use of symbols, a hallmark of modern human behavior. Others include the development of specialized tools, including flaked spear points and fishing nets, and the use of decoration.
Modern humans evolved in Africa some 100,000 years ago. About 50,000 years ago, they spread into Europe and began to displace the Neanderthals -- a separate humanlike species.
Almost all ancient traces of modern behavior, carved bone tools and cave paintings have been discovered in Europe. That fact has led paleoanthropologists such as Stanford's Richard Klein to suggest that some kind of behavioral revolution occurred 50,000 years ago which fueled improved abilities to hunt and gather, a population boom, worldwide migration and some artistic abilities.
Klein suggests the behavior changes were due to a biological advance, perhaps a change in the structure of the human brain. Others say the primary change more likely was cultural. Still others argue that no abrupt change occurred, but that art and culture developed slowly.
Early humans living in Africa, many surmised, led a more primitive way of life -- one that did not include symbolic artworks.
The newly discovered objects could challenge all of those assumptions. The find consists of seven carved pieces of ochre, a red stone used to make pigment powders. Ochre powder is often mixed with animal fat to create body paint for ceremonial and ritualistic use. Two of the ochre pieces carry what look to be abstract carvings: parallel lines in a crosshatched design.
Henshilwood said the patterns appear to be carefully and deliberately carved onto rocks that were rubbed smooth before the carving occurred. He believes the patterns are abstract symbols that were probably created by one artist but understood by others -- an ability that would likely require the use of language.
Others are more skeptical. Many of the skeptics say because the newly discovered etchings are not widespread throughout Africa, they may have been a fluke or the work of a single genius who left no cultural legacy.
Anthropologist Meg Conkey of the University of California, Berkeley, who has studied the world's oldest known paintings on the walls of France's Grotte Chauvet, says the more interesting question is why the carvings were found in this cave and not others.
Henshilwood suggests that the coastal dwellers who occupied the cave could have advanced more quickly because of a rich seafood diet.
He also predicts that more early African art will be found in other caves when African sites are excavated as well and as thoroughly as those in Europe.
But Klein, who has worked in several caves on the continent, including the Blombos cave where the new carvings were discovered, counters that there are excellent, recent excavations throughout Africa. If civilization was advanced so early, he asks, "Why are these (carvings) so rare?"
Anthropologists, much like modern art critics, are also vigorously debating the importance of the etchings. "Is it art, or somebody with a stone tool just sitting there scratching?" asked Klein, who said the patterns are "interesting" but not as compelling as the depictions of animals and humans that were created on cave walls 30,000 to 33,000 years ago.
Henshilwood discovered the Blombos site in 1991. The cave sits in a 120 foot high cliff overlooking the Indian Ocean and is 180 miles east of Cape Town.
In December, Henshilwood's team published the discovery of specialized, decorative flaked stone and bone tools in the cave. Found in 70,000 year old sand deposits, the tools suggested unexpected advancements in civilization.
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