70,000-year-old blades shed light on early human communication


A collection of 70,000-year-old sharp stone blades found in a South African cave suggests that humans were adept at producing advanced tools at that time and successfully passed down the technology from generation to generation, according to a report in Wednesday’s edition of the journal Nature.

The blades, called microliths, are small — about 3 centimeters long — and were likely used as the points of early weapons.

The evidence has generally been incomplete as to when and for how long early humans possessed the skills to produce and use tools like the microliths described in the study. While some researchers have argued that tools were in constant use, many others believe that tool use may have come and gone over time as population, climate and other factors varied, with people relearning how to make and use the same tools as the needs arose.


As a result, what may be most important about the newly found blades is not their age but the fact that they were dated to a period spanning about 11,000 continuous years. That suggests that by 70,000 years ago, humans possessed not only the capability to make these weapons and tools but also some sophisticated skills that would allow them to pass down the techniques for producing them over generations.

While the method by which such transmission occurred is unknown, the authors of the report argue that production of the tools would have been complicated enough to require what they call “high-fidelity transmission” between humans — in other words, a system of complex language.

That’s important because many researchers have argued that evidence of high-level cognition is best measured via the presence or absence of symbolism, generally represented by primitive artworks.

If researchers can prove an advanced language system existed 70,000 years ago, however, that may allow other skills to supplement art as the arbiter of early human intelligence.

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