On the south coast of South Africa, scientists have found evidence for an advanced stone age technology dated to 71,000 years ago at Pinnacle Point near Mossel Bay. This technology, allowing projectiles（落弹数） to be thrown at greater distance and killing power, takes hold in other regions of Africa and Eurasia about 20,000 years ago. When combined with other findings of advanced technologies and evidence for early symbolic behavior from this region, the research documents a persistent pattern of behavioral complexity that might signal modern humans evolved in this coastal location. These findings were reported in the article "An Early and Enduring Advanced Technology Originating 71,000 Years Ago in South Africa" in the November 7 issue of the journal Nature.

"Every time we excavate a new site in coastal South Africa with advanced field techniques, we discover new and surprising results that push back in time the evidence for uniquely human behaviors," said co-author Curtis Marean, project director and Arizona State University professor in the Institute of Human Origins, a research center of the College of Liberal Arts and Sciences in the School of Human Evolution and Social Change.

The reported technology focused on the careful production of long, thin blades of stone that were then blunted（钝的） (called "backing") on one edge so that they could be glued into slots carved in wood or bone. This created light armaments（军备） for use as projectiles, either as arrows in bow and arrow technology, or more likely as spear throwers (atlatls). These provide a significant advantage over hand cast spears, so when faced with a fierce buffalo (or competing human), having a projectile weapon of this type increases the killing reach of the hunter and lowers the risk of injury. The stone used to produce these special blades was carefully transformed for easier flaking by a complex process called "heat treatment," a technological advance also appearing early in coastal South Africa and reported by the same research team in 2009.

"Good things come in small packages," said Kyle Brown, a skilled stone tool replicator（复制基因） and co-author on the paper, who is an honorary research associate with the University of Cape Town, South Africa. "When we started to find these very small carefully made tools, we were glad that we had saved and sorted even the smallest of our sieved materials. At sites excavated less carefully, these microliths may have been discarded in the back dirt or never identified in the lab."

Prior work showed that this microlithic technology appear briefly between 65,000 and 60,000 years ago during a worldwide glacial phase, and then it was thought to vanish, thus showing what many scientists have come to accept as a "flickering" pattern of advanced technologies in Africa. The so-called flickering nature of the pattern was thought to result from small populations struggling during harsh climate phases, inventing technologies, and then losing them due to chance occurrences wiping out the artisans with the special knowledge.

"Eleven thousand years of continuity is, in reality, an almost unimaginable time span for people to consistently make tools the same way," said Marean. "This is certainly not a flickering（闪烁的） pattern."