Tools discovered in Kenya give glimpse of early human behavior
NEW YORK — Stone tools and other items from ancient sites in Kenya give a glimpse at the emergence of some key human behaviors, perhaps including a building of relationships with distant neighbors, new research says.
Scientists can’t be sure whether the objects were made by our species, Homo sapiens, or some close relative that’s now extinct.
But at about 320,000 years old, they’re roughly the same age or a bit older than the earliest known H. sapiens fossils, which appeared in Morocco.
In any case, they show “foundations of the origin of modern human behavior,” says Richard Potts of the Smithsonian Institution, one of the researchers reporting the find in three papers released Thursday by the journal Science.
The tools are much smaller and more sophisticated than the older, teardrop-shaped stone tools found in the same area in southern Kenya. Some were made of a volcanic rock, obsidian, that didn’t come from the area, meaning the toolmakers traveled miles to get it.
And those excursions must have led them to encounter groups of H. sapiens or our close evolutionary relatives. The toolmakers likely made connections with them so that they wouldn’t be threatened when they showed up on somebody else’s turf, the researchers said.
“I don’t think you would last very long if you went around grabbing someone else’s obsidian without their permission,” said Alison Brooks, an anthropology professor at George Washington University in Washington, D.C., and another author of the papers.
The newer tool style, known from other sites as Middle Stone Age technology, produced smaller stone flakes for uses like scraping and points on projectiles. It required a lot more planning to break off those chips to a desired size and shape, and so indicates a level of mental sophistication, Potts said.
Potts stressed that the researchers don’t claim that they’ve identified the birthplace of this tool style, but rather that the finds represent what was going on in at least one part of Africa.
The older stone tools are from 1.2 million to about 500,000 years ago. Then, because of the geology of the sites, nothing is preserved until 320,000 years ago, when “we have a total replacement” of the old tool style by a more advanced one, Potts said.
Analysis showed much of the obsidian was from places about 15 miles to 30 miles away in five different directions. So that means the toolmakers maintained mental maps of where to go find it, Potts said.
The researchers also reported finding evidence for use of pigments. Two rocks appeared to have been ground and chopped to produce a powder of the bright red ochre pigment they contained. Other rocks brought in from elsewhere contained manganese, which is a black pigment.
Eric Delson of Lehman College in New York said that when the new work is combined with other findings, “it is now clear that the time period around 300,000 years ago was a watershed for modern human [H. sapiens] origins across Africa.”