Scientists discover evidence of early human innovation, pushing back evolutionary timeline

Evidence of innovation dates to a period when humans faced an unpredictable and uncertain environment, according to three new studies.

SMITHSONIAN—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—by about 320,000 years ago—begun trading with distant groups, using color pigments and manufacturing more sophisticated tools than those of the Early Stone Age. These newly discovered activities approximately date to the oldest known fossil record of Homo sapiens and occur tens of thousands of years earlier than previous evidence has shown in eastern Africa. 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.

Evidence for these milestones in humans’ evolutionary past comes from the Olorgesailie Basin in southern Kenya, which holds an archeological record of early human life spanning more than a million 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.

“This change to a very sophisticated set of behaviors that involved greater mental abilities and more complex social lives may have been the leading edge that distinguished our lineage from other early humans,” said Rick Potts, director of the National Museum of Natural History’s Human Origins Program.

Potts has been leading the Human Origin Program’s research in Olorgesailie for more than 30 years in collaboration with the National Museums of Kenya. He is the lead author on one of the three Science publications that describe the adaptive challenges that early humans faced during this phase of evolution. Alison Brooks, a professor of anthropology at George Washington University’s Center for the Advanced Study of Human Paleobiology and an associate of the museum’s Human Origins Program, is lead author on the paper that focuses on the evidence of early resource exchange and use of coloring materials in the Olorgesailie Basin. A third paper, by Alan Deino at the Berkeley Geochronology Center and colleagues, details the chronology of the Middle Stone Age discoveries.

The first evidence of human life in the Olorgesailie Basin is dated to 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. But 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 ochre—at the sites, along with evidence that the rocks had been processed for use as coloring material. “We don’t know what the coloring was used on, but coloring is often taken by archeologists as the root of complex symbolic communication,” Potts said. “Just as color is used today in clothing or flags to express identity, these pigments may have helped people communicate membership in alliances and maintain ties with distant groups.”

Summing up the biggest takeaways from the Olorgesailie investigations, the National Center for Scientific Research (CNRS), whose own Francesco d’Errico played a key role in the research, reported “between 295,000 and 320,000 years ago, hominins present in Kenya’s Olorgesailie Basin were already making stone points they modified to serve as spear tips; transported high quality volcanic rocks over long distances (25–60 km) for knapping; hunted many species of animals, including small prey; and both collected and processed iron-rich ores, probably to obtain ocher powder……..Never before have such artifacts been found together, and in such large numbers.” This suggests, concludes the CNRS report, that “the ancestors of today’s humans developed key innovations and modern cognition as early as the initial phases of the Middle Stone Age.”

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.

Geological, geochemical, paleobotanical and faunal evidence indicates that an extended period of climate instability affected the region beginning around 360,000 years ago, at the same time earthquakes were continually altering the landscape. Although some researchers have proposed that early humans evolved gradually in response to an arid environment, Potts says his team’s findings support an alternative idea. Environmental fluctuations would have presented significant challenges to inhabitants of the Olorgesailie Basin, prompting changes in technology and social structures that improved the likelihood of securing resources during times of scarcity.

 

 

Image Gallery

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Kenya Map w Olorgesailie

Evidence for milestones in human evolution was found in the Olorgesailie Basin in southern Kenya, which holds an archeological record of early human life spanning more than a million years. Human Origins Program, Smithsonian

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Locality B, Olorgesailie, Kenya - DSCN0079 - 2005

A bird’s eye view of the Olorgesailie Basin in southern Kenya, which holds an archeological record of early human life spanning more than a million years. This landscape shows a shift in the environment between 500,000 years ago, which marks the last known evidence of the handaxe toolmakers in the Olorgesailie Basin, and the more recent sediments dated 320,000 years and younger, which preserve the Middle Stone Age evidence, including the color pigments and sophisticated tools made from obsidian. White and light brown sections of the landscape indicate the ancient lake and lakeside environment associated with older handaxe technology. Middle Stone Age archeological sites occur in the darker brown sediments, which mark the end of the stable lake environment and the onset of dramatic environmental unpredictability and uncertainty in the region marked by fluctuations between wet and dry conditions. Human Origins Program, Smithsonian 

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Olorgesailie BOK-1 Site JYellen

The emergence of long-distance trade, the use of color pigments and the crafting of sophisticated tools all approximately date to the oldest known fossil record of Homo sapiens and occur tens of thousands of years earlier than previous evidence has shown in eastern Africa. 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. At this Olorgesailie Basin excavation site, the Smithsonian team discovered key artifacts and pigments. Fossil bones found at the site also showed that a significant change in the kinds of animals in this region occurred around the same time as the transitions in human behavior. This turnover signaled that environmental conditions significantly changed and affected which animals could thrive in the region. Human Origins Program, Smithsonian 

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Excavation GOK-1

Geological, geochemical, paleobotanical and faunal evidence from the Olorgesailie Basin indicates that an extended period of climate instability affected the region beginning around 360,000 years ago, at the same time earthquakes were continually altering the landscape. Although some researchers have proposed that early humans evolved gradually in response to an arid environment, Potts said his team’s findings support an alternative idea. Environmental fluctuations would have presented significant challenges to inhabitants of the Olorgesailie Basin, prompting changes in technology and social structures that improved the likelihood of securing resources during times of scarcity. In this Olorgesailie Basin excavation site, red ochre pigments were found with Middle Stone Age artifacts. The light brown and gray layers provide evidence of ancient soils and of landscapes affected by earthquakes and other seismic activity, factors that rapidly altered the environment and resources on which human ancestors depended for survival. Human Origins Program, Smithsonian 

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alisonbrookexcavation

Excavation conducted by Alison Brook’s team at an Olorgesailie Middle Stone Age site. Francesco d’Errico, PACEA (CNRS/ University of Bordeaux/French Ministry of Culture)

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Olorgesailie Handaxes

Olorgesailie handaxes. The National Museums of Kenya loaned the artifacts pictured above to conduct the analyses published in Science. Human Origins Program, Smithsonian

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Olorgesailie Achulean Handaxes MSA points pigments

The first evidence of human life in the Olorgesailie Basin is dated to about 1.2 million years ago. For hundreds of thousands of years, people living there made and used large stone cutting tools called handaxes (left). According to three new studies published in Science, early humans in East Africa had—by about 320,000 years ago—begun using color pigments and manufacturing more sophisticated tools (right) than those of the Early Stone Age handaxes, tens of thousands of years earlier than previous evidence has shown in eastern Africa. The sophisticated tools (right) were carefully crafted and more specialized than the large, all-purpose handaxes (left). Many were points designed to be attached to a shaft and potentially used as projectile weapons, while others were shaped as scrapers or awls. The National Museums of Kenya loaned the artifacts pictured above to conduct the analyses published in Science. Human Origins Program, Smithsonian 

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Olorgesailie MSA StoneTools and Pigment

Olorgesailie MSA stonetools and pigment. The National Museums of Kenya loaned the artifacts pictured above to conduct the analyses published in Science. Human Origins Program, Smithsonian 

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MSA Pigments Manganese and Ochre

The research team also discovered black and red rocks—manganese and ochre—at the sites, along with evidence that the rocks had been processed for use as coloring material. “We don’t know what the coloring was used on, but coloring is often taken by archeologists as the root of complex symbolic communication,” Potts said. “Just as color is used today in clothing or flags to express identity, these pigments may have helped people communicate membership in alliances and maintain ties with distant groups.” The National Museums of Kenya loaned the materials pictured above to conduct the analyses published in Science. Human Origins Program, Smithsonian

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Refit point 1198 with core

Above and below: 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 significant quantities of the valuable stone across the ancient landscape. The National Museums of Kenya loaned the materials pictured above to conduct the analyses published in Science. Human Origins Program, Smithsonian 

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Refit point 1198 and core side by side

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Potts looking at Olorgesailie Handaxes

Above and below: Rick Potts, director of the National Museum of Natural History’s Human Origins Program at the Smithsonian. Above, he surveys an assortment of Early Stone Age handaxes discovered in the Olorgesailie Basin, Kenya. Courtesy of Jason Nichols. Below image courtesy Human Origins Program, Smithsonian

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Fossil Hippo Site, possible Olorongo Beds

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Alison Brooks

Alison Brooks, a professor of anthropology at George Washington University’s Center for the Advanced Study of Human Paleobiology and an associate of the National Museum of Natural History’s Human Origins Program at the Smithsonian, is lead author on the paper that focuses on the evidence of early resource exchange and use of coloring materials in the Olorgesailie Basin. Human Origins Program, Smithsonian 

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Article Source: Edited from the Smithsonian and CNRS news releases.

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The research teams for the three studies published in Science include collaborators from the following institutions: the Smithsonian Institution, the National Museums of Kenya, George Washington University, the Berkeley Geochronology Center, the National Science Foundation, the University of Illinois at Urbana-Champaign, the University of Missouri, the University of Bordeaux (Centre National de la Recherche Scientifique), the University of Utah, Harvard University, Santa Monica College, the University of Michigan, the University of Connecticut, Emory University, the University of Bergen, Hong Kong Baptist University and the University of Saskatchewan.

Funding for this research was provided by the Smithsonian, the National Science Foundation and George Washington University.

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