Scientists discover evidence of early human innovation
Anthropologists at the Smithsonian's National Museum of Natural History and an international team of collaborators have discovered that early humans in East Africa had begun trading with distant groups, using color pigments and manufacturing more sophisticated tools than those of the Early Stone Age. The new discovery date t the oldest known fossil record of Homo Sapiens.
These behaviors, which are characteristic of humans who lived during the Middle Stone Age, replaced technologies and ways of life that had been in place for hundreds of thousands of years.
The new discoveries, reported in three studies published March 15 in the journal Science, indicate that these behaviors emerged during a period of tremendous environmental variability in the region. As earthquakes remodeled the landscape and climate fluctuated between wet and dry conditions, technological innovation, social exchange networks and early symbolic communication would have helped early humans survive and obtain the resources they needed despite unpredictable conditions, the scientists say.
The first evidence of human life in the Olorgesailie Basin comes from about 1.2 million years ago. For hundreds of the thousands of years, people living there made and used large stone-cutting tools called handaxes. Beginning in 2002, Potts, Brooks and their team discovered a variety of smaller, more carefully shaped tools in the Olorgesailie Basin. Isotopic dating by Deino and collaborators revealed that the tools were surprisingly old--made between 320,000 and 305,000 years ago. These tools were carefully crafted and more specialized than the large, all-purpose handaxes. Many were points designed to be attached to a shaft and potentially used as projectile weapons, while others were shaped as scrapers or awls.
While the handaxes of the earlier era were manufactured using local stones, the Smithsonian team found small stone points made of non-local obsidian at their Middle Stone Age sites. The team also found larger, unshaped pieces of the sharp-edged volcanic stone at Olorgesailie, which has no obsidian source of its own. The diverse chemical composition of the artifacts matches that of a wide range of obsidian sources in multiple directions 15 to 55 miles away, suggesting exchange networks were in place to move the valuable stone across the ancient landscape.
The team also discovered black and red rocks--manganese and ocher--at the sites, along with evidence that the rocks had been processed for use as coloring material
Hoping to understand what might have driven such fundamental changes in human behavior, the research team integrated data from a variety of sources to assess and reconstruct the ancient environment in which the users of these artifacts lived. Their findings suggest that the period when these behaviors emerged was one of changing landscapes and climate, in which the availability of resources would have been unreliable.