The earliest known pieces of jewellery made by modern humans have been identified by scientists. The three shell beads are between 90,000 and 100,000 years old, according to an international research team. Two of the ancient beads come from Skhul Cave on the slopes of Mount Carmel in Israel. The other comes from the site of Oued Djebbana in Algeria. If the archaeologists' interpretation is correct, it means that human self-adornment, considered a manifestation of symbolic thinking, was practiced at least 25,000 years earlier than previously thought.
     The pea-sized items all have similar holes which would have allowed them to be strung together into a necklace or bracelet, the researchers believe. All three shells come from the same genus of marine mollusc known as Nassarius; they were probably selected for their size and deliberately perforated with a sharp flint tool. They represent a remarkable early expression of modern behaviour in the archaeological record, experts say.
     "The interesting thing about necklaces and this kind of behaviour is that it is symbolic. When we wear items like this, we are sending a message," said co-author Professor Chris Stringer of London's Natural History Museum. "The message may be that we are powerful, or wealthy, or sexy, that we're part of a particular group, or to ward off evil. They're not just decorative; we think they had a social meaning."
     Chemical and elemental analysis of sediments stuck to one of the shells from Skhul showed that it came from ground layers dated to 100,000 years ago. The style of tools at Oued Djebbana suggests the single specimen from this open-air site might be up to 90,000 years old. The authors' case for the shells having been used as beads is based on the remote location of the sites where they were found and the nature of the perforations in them.
     Up until recently, examples of modern behaviour before 50,000 years ago had eluded researchers, even though humans with modern-looking anatomy are known in the fossil record from about 195,000 years ago onward. This had led some researchers to propose that modern anatomy and modern behaviour did not evolve in tandem. Instead, they argued, a fortuitous mutation in the human brain may have triggered an explosion in human creativity 50,000 years ago, leading to a sudden appearance of personal ornaments, skilfully-crafted art, novel tools and weapons. The discovery of 75,000-year-old Nassarius shell beads at Blombos Cave in South Africa challenged this idea. These beads even bore traces of red ochre, used as a pigment. Now the dates for beads from Skhul and Oued Djebbana further weaken the "cultural explosion" scenario, says Stringer.
     But the apparent antiquity of symbolic behaviour raises questions about the time it took for modern humans to expand into the rest of the world. "There was a long period where modern humans survived in the African world and into part of the Near East, but never expanded into western Europe," Professor Ofer Bar-Yosef of Harvard University, US, said. Marian Vanhaeren, of University College London, who led the study, said: "We think that the African evidence may point to the beads being used in gift-giving systems which function to strengthen social and economic relationships. The European evidence suggests the beads were used as markers of ethnic, social and personal identity."
     The marine shells from Skhul are held by the Natural History Museum in London, while the shell bead from Oued Djebbana is held by the Museum of Man in Paris.

Sources: BBC News, The New York Times (22 June 2006), The Times, The Guardian (23 June 2006)