In the 4.5-billion-year history of Earth, 80,000 years is the blink of an eye.
But in terms of human evolution, it has the potential to be a drastic shift. A team of archaeologists and anthropologists believe that length of time may be just how much earlier our ancestors began using their brains to develop basic skills.
It has been commonly believed that around 200,000 years ago, human ancestors began to become cognitively “modern.”
“That is, when did we begin to think in ways that are common for humans today and distinct from non-modern humans?” said Karl Hutchings, an assistant professor in sociology and anthropology at Thompson Rivers University in Kamloops, B.C., and a member of a team of researchers on a recent dig in Ethiopia.
Some members of the research team speculate discoveries at the site, known as the Gademotto Formation, could move the timetable for brain development to about 280,000 years ago.
A research paper published by the team said the discovery is significant “because it provides direct evidence for a highly advantageous, complex technology that predates the emergence of Homo sapiens.”
Prof. Hutchings, however, is doubtful, because the new data would indicate a different date for the emergence of Homo sapiens – a group that includes humans and their ancestors – and because there have been no sites found with similar tools that were used in that time period.
“I’m not as convinced,” he said.
The area has several sites where hominids, a subgroup of Homo sapiens, have been found.
Prof. Hutchings said he was invited because he is the only person who does the type of archaeological analysis necessary – one that uses sound waves and measurements to break stones and, from that, determine how they were made and why they were used.
He studied more than 200 javelin-shaped, mostly obsidian projectiles found at the site along a large collapsed volcano crater in the country’s Rift Valley.
His research involved analyzing the fractures in the stone and using the results to determine how the objects were used. Fractures are different based on whether the objects are thrown or used as a hand tool, for example.
He hopes to return to Ethiopia to visit the Gademotto Formation again for further investigation.
Whatever the results of the study, Prof. Hutchings said the work will have an impact.
He said we can better understand our place in the cosmos and where we are headed if we better understand ourselves.
“Of course, we can’t witness or dig up these behaviours, so archaeologists look for indications of these behaviours among things that do preserve; in this case, specific stone tools, since stone preserves so well,” he said.
“So, I am seeking to identify that place and time where we began to think in ways that characterize modern humans.”
Once the timeline of where and when our ancestors began to evolve is more clear, research can concentrate on why, he said.
“It’s always the ‘why’ questions that are most fascinating.”