Archeologists have identified what might be the world's oldest known jewelry. It consists of 100,000-year-old shells from the Middle East with holes bored in their centers. If the shells were used as beads for personal decoration, it means symbolic human thinking and the first signs of culture are much older than previously thought.
When we adorn our bodies with rings, necklaces, coloring or some other decoration, we behave in a way that University of California archeologist John Bower says is uniquely human.
"Self adornment is a very important and perhaps the only really convincing archeological evidence that we have of self recognition, and self recognition is fundamental to the emergence of the kinds of behavior that we call human culture," he said.
Until recently, researchers believed that the first signs of modern human culture appeared about 40,000 years ago when anatomically modern humans arrived in Europe.
But two years ago, scientists pushed that date way back when they found 75,000-year-old perforated shells from Blombos cave in South Africa. They said the type of holes and the wear patterns around the holes showed they were clearly worn as beads.
Now, the same team has found even older perforated shells - 25,000 years older - two of them from Skhul in Israel and a third from an Algerian site named Oued Djebbana.
The three shells are from the same tiny snail-like creature they had excavated in South Africa in 2004, but these specimens were dug up by other scientists in the 1940s and were hidden away in London and Paris museums.
University College London researcher Marian Vanhaeren and colleagues came across them in the museums and analyzed crusted dirt that stuck to the Israeli shells. Vanhaeren told Science magazine, where the research appears, that the dirt came from the same layer in Skhul that had yielded human skeletons at least 100,000 years old, meaning the two shells from there are also that old.
"This find indicates the anatomically modern humans from Africa and the Near East created beadwork traditions well before their arrival in Europe, and that there were modern human cultures in Africa quite early in time," Vanhaeren said.
As for the single shell from Algeria, the researchers say it could be up to 90,000 years old based on the style of tools found there.
But the sample size from both locations is very small and the origin of the holes is not nearly as obvious as those on the shells they had found in South Africa. Vanhaeren argues that Skhul and Oued Djebbana are so far from the sea that the shells were probably brought there intentionally, most likely for beadworking.
By studying modern specimens of the shells, her team also determined that the chances the holes occurred naturally are extremely small.
"Unfortunately, the state of preservation of the Skhul and Oued Djebbana sites is such that we cannot reach a definite conclusion as to the human origin of the wear," Vanhaeren said. "In other words, our argument for the symbolic use is based on the remoteness from the sea and the presence of unusual perforations."
Stanford University archeologist Richard Klein is not satisfied. He did not accept the earlier findings from Blombos Cave in South Africa, suggesting that the holes in the shells and wear patterns could have been caused by soil compacting over time. He supports the view that modern human culture and the use of symbolism exploded 40,000 years ago in Europe. Klein told Science magazine that the newest evidence showing otherwise appears weak.
But John Bower of the University of California is more accepting of the evidence, although he acknowledges its shortcomings.
"It is a reasonable argument for the so-called beads to not be occurring naturally in the places where they are found. These are not creatures that can travel 200 kilometers across desert conditions to an archeological site," he said. "They must have been transported there some how, most likely by human beings, although it is not impossible to rule out transport by, for example, birds."
But Bower says a larger question remains. How quickly did anatomically modern humans acquire culture and symbolic expression? Was it rather suddenly or much more slowly over tens of thousands of years?
"That is a major problem in paleoanthropology that this article contributes toward, but is a long way from resolving," he said.