Ancient Stone Tools Spark Evolution of Human Language, Teaching

Ancient stone tools used by our hominin ancestors in the African savanna, aside from being excellent slicers of hunted game animals like zebra and gazelle, also sparked the evolution of human language and teaching, according to a new study.

About two and a half million years ago during the Stone Age, our ancestors crafted these slaughtering tools, known as Oldowan tools, as a means of survival. And now, according to this new study, they played an important part in the development of complex communication - more complex for the time than previously thought.

"Our findings suggest that stone tools weren't just a product of human evolution, but actually drove it as well, creating the evolutionary advantage necessary for the development of modern human communication and teaching," lead author Thomas Morgan, at the University of California, Berkeley, said in a statement.

The art of Oldowan stone-knapping - which involves hammering a hard rock against certain volcanic or glassy rocks to create butchering "flakes" - dates back to the Lower Paleolithic period in eastern Africa. This technique spread throughout the continent over the next 700,000 years, that is until more sophisticated hand-axes and cleavers came on the scene.

To find out how stone-knapping became such an evolutionary force among early hominins, researchers explained to 180 college students the art of Oldowan stone-knapping, finding that verbal communication yielded the most flakes of good quality in the least amount of time. Also, by creating "learning chains," in which one person would demonstrate the technology to another, they found that they picked it up rather quickly.

"If someone is trying to learn a skill that has lots of subtlety to it, it helps to engage with a teacher and have them correct you," Morgan said. "You learn so much faster when someone is telling you what to do."

Of course, early hominins likely did not speak yet, but over the course of evolution as more advanced tools were made, they likely helped spark communication with one another.

"At some point they reached a threshold level of communication that allowed Acheulean hand axes to start being taught and spread around successfully and that almost certainly involved some sort of teaching and proto-type language," Morgan added.

The findings are described further in the journal Nature Communications.

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