100,000 year-old beads suggest modern culture emerged earlier than previously thought

Source: Eurekalert

Three shells with holes bored into their centers, excavated from sites in Israel and Algeria, may be the oldest known evidence of personal decoration.

New findings suggest that the shells are 100,000 year-old beads, which lends support to the idea that modern human behavior emerged gradually instead of bursting forth later in Europe. The study appears in the 23 June 2006 issue of the journal Science, published by AAAS, the nonprofit science society.

"Our paper supports the scenario that modern humans in Africa developed behaviors that are considered modern quite early in time, so that in fact these people were probably not just biologically modern but also culturally and cognitively modern, at least to some degree," said study coauthor Francesco d'Errico of Centre National de la Recherche Scientifique Unité Mixte de Recherche (CNRS UMR) in Talence, France.

"This idea has been postulated before now, but the evidence has been quite scant," he said.

Until recently, researchers generally believed that the first signs of modern human culture appeared 40,000 years ago, when anatomically modern humans arrived in Europe. The cave paintings, musical instruments, jewelry and other artwork preserved from this time period, the Upper Paleolithic, indicate that humans were capable of symbolic thinking.

Jewelry probably conveyed many aspects of people's social and cultural identities, and most archaeologists agree that personal decoration was one of the most important expressions of modern human culture, according to study coauthor Marian Vanhaeren of University College London in London and CNRS UMR in Nanterre, France.

In a previous study, d'Errico and Vanhaeren reported, along with other colleagues, the discovery of perforated shells from Blombos cave in South Africa (Science, 16 April 2004). These beads were dated to about 75,000 years ago.

D'Errico and Vanhaeren wanted to find beads from more than a single site, however, in order to firmly establish that beadworking was underway earlier than was previously thought.

The two researchers and their colleagues searched through museum collections and found bead-like shells from the sites of Skhul, in Israel, and Oued Djebbana, in Algeria. The shells were the same genus as those found at Blombos and were perforated in a similar way.

"It's very important to establish the chronology of these modern types of behaviors, and this paper constitutes we think a significant advancement," said d'Errico.

Archaeologists excavated Skhul in the early 1930s using less meticulous methods than archaeologists use today, so the Science authors had to do some additional work to determine exactly where the shells came from and how old they were.

One of the site's sediment layers contained a series of human skeletons, which recent dating efforts placed at 100,000 to 135,000 years old. Coauthor Sarah James, a researcher at the Natural History Museum, London, where the Skhul specimens are kept, analyzed the crust of sediment stuck to one of the two shells and found that the shells came from the same sediment layer that the skeletons did.

The relatively large size of the shells from Skhul and Oued Djebbana also seems to confirm their old age, since this species was bigger 100,000 years ago than it is today, the authors say.

Oued Djebbana was excavated in the late 1940s. Currently just a single radiocarbon date is available, indicating that the site is more than 35,000 years old. Based on the technology and style of the stone tools found there, however, the site could be up to 90,000 years old, according to the authors.

The shells, Nassarius gibbosulus, are scavenging marine snails that live in shallow waters and are now only found in the central-eastern Mediterranean.

The sample size is small, but the authors argue that Skhul and Oued Djebbana are so far from the sea -- 200 km in case of Oued Djebbana -- that the shells must have been intentionally brought there, most likely for beadworking. By studying modern Nassarius shells from Mediterranean beaches, they also determined that shells with single holes in the centre are rare in nature and that Skhul and Djebbana inhabitants must have purposely perforated or deliberately picked out such shells, arguably for symbolic use.

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