Oldest butchery tools sparked evolution of human communication

Stone tools used by our oldest hominin ancestors 2.5 million years ago may have sparked the evolution of human communication, a new study has found.
Our hominin ancestors in the African savanna, two and a half million years ago, crafted rocks into shards that could slice apart a dead gazelle, zebra or other game animal, researchers said.
Over the next 700,000 years, this butchering technology spread throughout the continent and came to be a major evolutionary force, said researchers from the University of California, Berkeley, the University of Liverpool and the University of St Andrews.
They have found compelling evidence for the co-evolution of early Stone Age slaughtering tools and our ability to communicate and teach, shedding new light on the power of human culture to shape evolution.

The study suggests communication among our earliest ancestors may be more complex than previously thought, with teaching and perhaps even a primitive proto-language occurring some 1.8 million years ago.
"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," said Thomas Morgan, lead author of the study and a postdoctoral researcher in psychology at UC Berkeley.

"Our data show this process was ongoing two and a half million years ago, which allows us to consider a very drawn-out and gradual evolution of the modern human capacity for language and suggests simple 'proto-languages' might be older than we previously thought," Morgan added.

Researchers conducted experiments in teaching humans the art of 'Oldowan stone-knapping', in which butchering 'flakes' are created by hammering a hard rock against certain volcanic or glassy rocks, like basalt or flint.
Oldowan stone-knapping dates back to the Lower Paleolithic period in eastern Africa, and remained largely unchanged for 700,000 years until more sophisticated Acheulean hand-axes and cleavers, which marked the next generation of stone tool technology, came on the scene.
In testing five different ways to convey Oldowan stone-knapping skills to more than 180 college students, the researchers found that the demonstration that used spoken communication - versus imitation, non-verbal presentations or gestures - yielded the highest volume and quality of flakes in the least amount of time and with the least waste.

The seeds of language, teaching and learning were planted due to the demand for Oldowan tools, the researchers said, and at some point hominins got better at communicating, hence the advent of Acheulean hand-axes and cleavers some 1.7 million years ago.
"To sustain Acheulean technology, there must have been some kind of teaching, and maybe even a kind of language, going on, even just a simple proto-language using sounds or gestures for 'yes' or 'no,' or 'here' or 'there,'" Morgan said.