for National Geographic News
Ostrich-eggshell beads found in Africa show that human beings were capable of symbolic thinking much earlier than previously thought, a team of scientists reports.
Anatomically modern humans (homo sapiens)people who looked pretty much like we do nowarose in Africa around 130,000 years ago. The question debated by archaeologists and anthropologists is: How smart were they?
One school of thought holds that while early human ancestors became anatomically modern while still in Africa, the development of modern behavioral traits lagged, emerging relatively suddenly only about 45,000 years ago. Around that time waves of modern humans began leaving Africa and colonizing the rest of the world.
Proponents of the cultural-lag idea suggest that a sudden genetic change, an increase in population density that spurred technological and cultural innovation, or other factors triggered the exodus out of Africa and the explosion of cultural change which occurred in Europe.
Others argue that "behavioral modernity" evolved in Africa and has a much longer history.
The ostrich-eggshell beads recovered from a site in the Serengeti National Park in Tanzania are believed to be about 70,000 years old, according to a team of scientists.
The team is speaking today at the annual meeting of the Paleoanthropology Society taking place this week in Montreal. The research was supported in part by the National Geographic Society's Committee for Research and Exploration and the Leakey Foundation.
If the dates are correct, there was modern human behavior in Africa about 35,000 years earlier than previously thought, strengthening the argument that "behavioral modernity" evolved hand-in-hand with anatomical modernity.
Beads are "unambiguous examples of symbolic behavior," said Curtis Marean, one of the paper's presenters. Marean is an anthropologist at the Institute of Human Origins at Arizona State University. "Once we get some definitive dating, [the find] could have a major impact on the evolution of symbolic thinking."
Complicating the debate is the fact that there is no consensus definition for what constitutes modern behavior.
Beadmaking is considered evidence of symbolic thinking becausewhether used for jewelry to show status or group identity or used in tradeit has little to do with survival. Other traits thought of as "modern" include the ability to plan ahead, innovate technologically, establish social and trade networks, create art, and adapt to changing conditions and environments.
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