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 now - arose 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, report nationalgeographic.com
The artifacts have not been properly dated but the scientists believe they are older than 40,000 years and if so, will challenge two popular theories - that humans did not develop symbolic thinking until about 35,000 years ago and that when it happened, it happened first in Europe.
The site, at the Serengeti National Park, is at least 40,000 years old and perhaps far older, dating to what is called the Middle Stone Age. While Middle Stone Age humans were physically modern, there has been debate about their culture and behavior.
The Middle Stone Age in East Africa began as early as 280,000 years ago. The Later Stone Age started about 45,000 years ago.
"This is very precocious," said John Bower, professor emeritus of anthropology at Iowa State University, who helped lead the study, inform reuters.co.uk
According to newscientist.com pettitt also points out that 70,000-year-old ochre crayons, covered with carvings that might have symbolic relevance, have already been recovered from the Blombos Cave in South Africa. Mabulla and his US colleagues acknowledge this, but argue that the ostrich shell beads are much less ambiguous.
Fossil records show that Homo sapiens evolved in its current physical form around 120,000 years ago. But it took some time for modern behaviour to develop and be expressed in the artefacts that are found today.