WASHINGTON -- Some 75,000 years ago, in a Stone Age cave overlooking the ocean, someone collected shells and bored holes in them, producing the oldest known evidence that humans had fashioned an ornament.
Discovery of the set of beads pushes back by some 30,000 years the first indications of the ability to make and use such symbolic materials.
The find, reported in Friday's issue of the journal Science, adds support to the idea that such symbolic thought developed very early among humans.
"Evidence for an early origin of modern human behavior has long remained elusive," said Christopher Henshilwood of the Centre for Development Studies, University of Bergen, Norway.
The new find at Blombos cave on South Africa's Indian Ocean coast provides well-dated evidence of human's using symbolic items, "an unambiguous marker of modern human behavior," said Henshilwood, lead researcher in the study.
Some researchers have argued that the ability to use symbolism did not arrive until later in human development, after people had migrated from Africa to the Middle East and Europe.
The previously oldest known human ornaments are perforated teeth and eggshell beads from Bulgaria and Turkey, dated 41,000- to 43,000-years-old, and 40,000-year-old ostrich-shell beads from Kenya.
The 41 Blombos cave beads were made from the shells of a type of mollusk. Holes were bored in the shells, each less than a half-inch across. The beads show wear marks indicating rubbing against thread, string or fabric, the researchers say, and contain traces of red color, either from decoration or from rubbing against colored materials. They were found in groups of up to 17 beads.
Last year, the same cave yielded two pieces of 77,000-year-old ocher cut with abstract patterns.
Beads are a serious matter in traditional societies, providing identification by gender, age, social class and ethnic group, Henshilwood said.
The ability to use language "must have been essential for sharing and transmitting the symbolic meaning of beads, and possibly other artifacts, within and beyond the group," he said.
Henshilwood said the mollusks used to make the beads live in estuaries and that the nearest source for them was some 12 miles away from the cave, indicating some time and effort was needed to obtain them. Wear marks on the beads indicate they were in use for a long time, he said.
Alison Brooks, who teaches anthropology at George Washington University, said she thinks the beads are "an unequivocal argument that people are employing symbols to signify who they are."
There is a great argument over the degree to which humans engaged in symbolic activity before they left Africa, and this find indicates they had that ability early, said Brooks, who was not part of the research team.
Anthropology professor Sally McBrearty of the University of Connecticut agreed that the find pushes back the earliest date of human symbolic activity. "I think this date will be pushed back further, ultimately," she said.
Noting that the beads were found in the same cave as the carved ocher, she said, "Whatever is happening there, something symbolic is being communicated."
One omission, she said, was that the researchers did not suggest how the shells had been perforated to form the beads.
In addition to Henshilwood, who is also affiliated with the State University of New York at Stony Brook, the research involved scientists from France, South Africa and Wales. The study was funded by the National Science Foundation, South African National Research Foundation, French National Center for Scientific Research, European Science Foundation, University of Bergen, Anglo American Chairman's Fund and the British Council.
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