John J. Shea is an archaeologist. He is also a flintknapper, or someone who makes stone tools. While on a dig at a 195,000-year-old site in the Lower Omo River Valley Kibish Formation in Ethiopia, he was given pause by the stone tools our supposedly “primitive” human ancestors had left behind. Nothing about the tools seemed archaic or primitive in the least; they were made by hands that skillfully manipulated a range of rock types, and were not all that different from what a flintknapper could make today. What separates these “primitive” flintknappers from “modern” humans?
Maybe not much, says Shea, a professor at Stony Brook University. Archaeologists have for too long perpetuated the idea that there are distinct primitive and modern periods, with a revolution occurring between the Middle and Upper Paleolithic periods (roughly 40,000 years ago). In fact, fossil evidence challenging that view has been around for decades.
From the 1970s onward, archaeologists based their idea of the Paleolithic revolution on artifacts from Europe, where they had found fossils of Homo sapiens with Upper Paleolithic tools dating back 35,000 years, and Homo neanderthalensis and other protohumans with earlier tools. But later, when they began to look outside Europe, in Asia and Africa, they found much older Homo sapiens—some dating as far back as 200,000 years—with the same primitive tools once associated with Neanderthals. To accommodate this evidence, archaeologists theorized that modern behaviors emerged tens of thousands of years after the earliest Homo sapiens.
The tendered explanation is a nice way of fitting the evidence to a long-cherished narrative, but it is not really scientific, Shea says. The archaeological record shows that “modern” behaviors have cropped up in different regions for long periods of time but then vanished. (Archaeologists label sites yielding this kind of evidence “precocious,” which, according to Shea, merely reflects these scientists’ bias.) If modernity were a revolutionary shift, why would it disappear for prolonged periods?
Shea believes that things such as sophisticated stone tools don’t appear because of sudden shifts in human abilities. Humans create them because their particular environment demands them, and because they can build on the technological advances of their forebears. Rather than focus on the illusory progress of Homo sapiens, Shea argues, archaeologists should study variations of human behavior from place to place.
If you look at stone tools produced in eastern Africa from 284,000 to 6,000 years ago, you don’t find a steady accumulation of different technologies, but constant and wide variation depending on the needs Homo sapiens faced given the environmental conditions of the time. In recent centuries humans have exhibited great variation in stone tool technology, but “no anthropologists in their right minds would attribute this variability to evolutionary differences,” Shea says.
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The Source: "Refuting a Myth About Human Origins" by John J. Shea, in American Scientist, March-April 2011.
Photo courtesy of Flickr/Matt Celesky