By chemically matching sediment samples from a shell exterior and a human bone from the Israeli site, Vanhaeren and her team were able to date the shell to between 100,000 and 135,000 years ago.
Radiocarbon dating of the Algerian site shows that the shell found there is more than 35,000 years old.
The researchers believe the African shell could be up to 90,000 years old, based on the technology and style of stone tools found there.
Until recently the earliest evidence for sophisticated human behaviorincluding the use of specialized tools and personal decorationcame from 40,000-year-old sites in Europe.
This gave rise to the theory that a sudden creative explosion took place among ancient humans, possibly due to changes within the brain.
But this theory has been hotly contested over the last two years, following discoveries of beads from far older sites.
In March 2004 John Bower at the University of California, Davis, and his colleagues announced the discovery of 70,000-year-old ostrich eggshell beads in Tanzania, Africa (see Tanzania map).
(Read "Is Bead Find Proof Modern Thought Began in Africa?" .)
Meanwhile, a study by Vanhaeren, d'Errico, and others, published in April 2004, described 75,000-year-old perforated shells from a cave in South Africa.
(Read "Oldest Jewelry? "Beads" Discovered in African Cave" .)
"The latest evidence indicates that people used a symbolic way of communicating well before the supposed revolution 40,000 years ago," d'Errico said of the new study.
But not everyone is convinced by the team's latest findings.
"The evidence that the new shells are beads seems weak to me," said Richard Klein, an anthropologist at Stanford University in Palo Alto, California.
"The evidence [from the South African cave research] is better, if only because there are many more specimens and their [archaeological] context is much better documented."
Beads or Shells?
Others support the idea that the early shells are beads.
"I am sure the shells were used by humans, either to adorn the dead or for day-to-day decoration," said Daniella Bar-Yosef Mayer, an archaeologist at the University of Haifa in Israel.
She first identified the Israeli shell beads and wrote about them in the French journal Paléorient in 2005.
D'Errico is confident that further excavations will uncover more shell beads and show that they were a common ornamentation prior to 40,000 years ago.
"We have data from other sites, which are unpublished as yet. The Science paper is just the first in a series of more robust data," he said.
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