The use of stone hammers to produce sharp stone flakes—knapping—is traditionally thought to be a process that ancient humans started doing intentionally or by accident before looking for things, such as animal carcasses and hard fruits, to cut. It is a defining feature of hominins and is seen as a massive leap of inspiration, or a “eureka!” moment around 3 million years ago. However, six Kent State researchers and their team suggest there may be more to the story.
Metin Eren, Ph.D., published a research paper in Archaeometry arguing that the origin of knapping was instead a cumulative process that involved hominins attempting to recreate the naturally occurring sharp stones, or “naturaliths,” they had already been using as cutting tools. Eren said hominins could have been using natural sharp edges as tools for millennia before ever attempting to craft them.
“We propose that naturaliths could have acted as a crucial link in the origin of technology for meat cutting and the eventual emergence of the deliberate production of stone flakes via percussion,” Eren said.
Eren and his team compiled multiple examples of naturaliths, including stones from Antarctica which resemble hominin tools that could only have been produced by natural processes since the continent was never inhabited. Other examples of naturaliths were documented in Ireland, South Africa, Oman, Brazil and Kenya. “Despite statements in the scientific literature that say otherwise, Mother Nature is producing knives all over the place,” Eren said in a NewScientist article.
The hypothesis is rooted in the idea that for a creature to adopt an item, selective pressure must occur first. Eren said the appeal of the hypothesis lies in the way “it shortens the cognitive distance between every step in the origin of technology” and offers a straightforward explanation for how hominins invented stone-cutting tools. "This is important because the production of stone tools led to a 3-million-year-long technological trajectory that continues to this day," he said.
Eren recognizes that many other tests need to be conducted to support the hypothesis, but its promise lies in its evolutionary foundation, its simplicity and its lack of assumptions. Some findings to support the hypothesis would include distinctive wear patterns or traces of plant and animal material on the edges of naturaliths at sites dating to 3-6 million years ago.
"Now we need to get to the field and look to see whether naturaliths exist; if they do, the archaeological record may get a whole lot older," Eren said.
Other Kent State professors who co-authored the paper include Michelle Bebber, Ph.D., Mary Ann Raghanti, Ph.D., and Owen Lovejoy, Ph.D., of the Department of Anthropology, as well as Earth Science Professors Joseph Ortiz, Ph.D., and David Singer, Ph.D. The Cleveland Museum of Natural History's Assistant Curator, Emma Finestone, Ph.D., was also a co-author of the new hypothesis.
To read the full research paper, please visit https://onlinelibrary.wiley.com/doi/full/10.1111/arcm.13075.
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