The ancient hominid used heat in order to produce "sophisticated tools" more than 300,000 years ago.
It should no longer come as a surprise that ancient humans were far more advanced than we were led to believe. This idea, firmly rejected until not so long ago, has recently been reaffirmed. Scientists have found that not only did human ancestors know how to use fire, they also developed sophisticated technologies for making tools.
This discovery was made by researchers from the Weizmann Institute of Sciences who used their own cutting-edge technologies to take a look at a collection of stone tools.
Their results suggest that the first humans to make them may have had a good understanding of the effects of heating stone before chipping it into sheets, and may even have used different temperatures to create different types of tools. This implies an excellent understanding of heat and how it can be used to manipulate materials.
Some of the tools analyzed were discovered at the Qesem Cave, a site in central Israel, which was excavated by Professor Avi Gopher and his colleagues at the University of Tel-Aviv. The fragmented tools that were found in the cave were dated to be between 420,000 and 200,000 years old, which means they were likely crafted during the Lower Paleolithic.
The discovery further proves that early humans had highly developed skills already hundreds of thousands of years ago.
The ancient hominids (a group that included members of the modern hominin group as well as extinct members of our family tree) lived in the Qesem Cave and the left behind tens of thousands of stone tools.
These tools are made primarily from flint, a hard grey rock consisting of nearly pure silica, and a material that is available throughout the country, and were produced in a process called carving, that is, using another stone or tool to chip pieces, sharpening an edge.
Sometime between 300,000 and 400,000 years ago, the main source of food that these hominids hunted changed from elephants to deer. The ancient people understood very well that they needed to adapt and change their hunting methods and tools. And so they did, as we now have evidence that suggests this change in hunting led to a change in the weapons used, requiring much finer hunting equipment that the ancestors eventually developed and crafted.
The question posed by Weizmann’s research group was whether the ancient inhabitants of the area could have used fire to temper the flint before carving it. Many later groups – less than 100,000 years ago – had left evidence of having used fire to make weapons since heat makes the stone easier to mold.
However, at sites of this age, there is usually almost no organic matter left that can give researchers conclusive evidence of fire use.
The team turned to a technique known as Raman spectroscopy. Scientists needed to first collect flint from areas near the Qesem Cave, as well as from other places in the country. After heating the pieces of flint to different temperatures and cooling them again, the researchers examined them with the tools in the laboratory, which revealed the composition of these rocks down to their chemical and molecular structure.
They then looked for similarities between what they had done in their experiment and what the ancient tools were showing.
As was expected, the experiment produced a large amount of data, which turned out to be too large to analyze with regular methods.
Scientists were therefore forced to turn to machine learning techniques and artificial intelligence, so despite the deviation from their normal biological research, they found patterns in large amounts of data that were up to their standards.
The group then applied spectroscopy and AI analysis to samples chosen at random from the thousands of pieces of ancient carved flint excavated from Qesem Cave.
One version of the findings compared three different types of flint artifacts and revealed three unique temperature ranges, one for each type. The first type, which scientists call pot lids, were small, chipped fragments, and analysis showed that they had been exposed to a higher temperature for enough to make the pieces of flint fly off on their own.
That told the team that their analysis was on the right track, as very high heat, up to 600 degrees Celsius, had been suggested in other studies to create the nicks and chips identified on the tools.
The second type of pieces are known as flakes, and the third are blades: larger, knife-like tools with a long, sharp edge and a thicker, front edge where they can be held.
The flakes, cutting tools essentially smaller than the blades, showed evidence of having been treated in a relatively large temperature range while the blades had been heated to lower temperatures (about 200-300 degrees).
In other words, it seemed as if the ancient inhabitants of the cave had intentionally used different fire at different temperatures to create different tools. This implies that whoever crafted the tools had a developed understanding of how fire worked and what was needed to be done in order to obtain specific results.
Such discoveries completely blow my mind. It tells us that hundreds of thousands of years ago, a people roaming lands that we can’t even imagine today developed–perhaps out of necessity–technologies that we cannot begin to understand today. When I say technologies, I don’t mean lasers or flying vehicles, but tools, techniques, and the means to create, to construct, and to survive.
These types of discoveries tell us that our ancestors were far more advanced than we have been led to believe to this day. It tells us that the development of the very “source code” of ancient civilization needs to be reevaluated and looked at from a different perspective.
I believe that we are far from understanding the exact level of development of ancient humans that lived 50,000 years ago, let alone groups that roamed the Earth 100,000, 200,000, or more than 300,000 years ago.
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Sources and references: DOI https://doi.org/10.1038/s41562-020-00955-z / all other sources are cited throughout the article.