domingo, 4 de abril de 2010
COULD these lines etched into 60,000-year-old ostrich eggshells (see photo) be the earliest signs of humans using graphic art to communicate?.
Until recently, the first consistent evidence of symbolic communication came from the geometric shapes that appear alongside rock art all over the world, which date to 40,000 years ago. Older finds, like the 75,000-year-old engraved ochre chunks from the Blombos cave in South Africa, have mostly been one-offs and difficult to tell apart from meaningless doodles.
The engraved ostrich eggshells may change that. Since 1999, Pierre-Jean Texier of the University of Bordeaux, France, and his colleagues have uncovered 270 fragments of shell at the Diepkloof Rock Shelter in the Western Cape, South Africa.
They show the same symbols are used over and over again, and the team say there are signs that the symbols evolved over 5000 years. This long-term repetition is a hallmark of symbolic communication and a sign of modern human thinking, say the team (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0913047107).
The eggshells were probably used as containers, and the markings may have indicated either the shells´ contents or their owner. Texier points out that until recently, bushmen in the region carved geometric motifs on ostrich eggshells as a mark of ownership. If the symbols do signify ownership, it could have implications for the evolution of human cognition. Iain Davidson, an Australian rock art specialist at the University of New England in Armidale, New South Wales, has suggested that marking ownership must have come after humans became self-aware. The eggshells could help to illuminate when this happened in this part of the world, he says.
Written language may have evolved more than once in human history. `Judging from what we know about the evolution of art all over the world, there may have been many traditions that were born, lasted for some time and then vanished,´ says Jean Clottes, former director of research at the Chauvet caves in southern France. `This may be one of them, most probably not the first and certainly not the last.´