St Andrews University research finds ancient stone tools shaped evolution


REASEARCH from the University of St Andrews has revealled that the stone tools of our ancestors sparked the evolution of language, teaching and learning.


The research, published today (Wednesday January 14, 2015) in the journal Nature Communications, was lead by St Andrew’s University biologist Dr Thomas Morgan.


The study brought together expertise in psychology, evolutionary biology and archaeology and found that human culture shaped evolution.


St Andrew’s University


Dr Morgan and a team of researchers from the University of California, Berkeley, the University of Liverpool and University College London found compelling evidence for the co-evolution of early Stone Age slaughtering tools and our ability to communicate and teach.


The study is the largest to date to look at gene-culture co-evolution in the context of prehistoric Oldowan tools, the oldest-known cutting devices. It suggests communication among our earliest ancestors may have been more complex than previously thought, with teaching and perhaps even a primitive proto-language occurring as early as 1.8 million years ago.


Dr Thomas Morgan, lead author of the study and currently a researcher in psychology at UC Berkeley, said:”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.


“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.”


Dr Morgan and University of Liverpool archaeologist Natalie Uomini arrived at their conclusions by conducting a series of experiments in teaching contemporary 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 were developed. Stone-knapping was practiced by some of our earliest ancestors, such as Homo habilis and the even older Australopithecus garhi, who walked on two legs, but whose facial features and brain size were closer to those of apes.


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.


To measure the rate of transmission of the ancient butchery technology, and establish whether more complex communication such as language would get the best results, study volunteers were divided into five- or 10-member “learning chains.”


The head of the chain received a knapping demonstration, the raw materials and five minutes to try their hand at it. That person then showed it to the next person in the chain, who in turn showed the next person, and so on. Their competence picked up significantly with verbal instruction.


Dr Morgan explained: “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. You learn so much faster when someone is telling you what to do.”


As for what the results mean for the Oldowan hominins: “They were probably not talking. These tools are the only tools they made for 700,000 years. So if people had language, they would have learned faster and developed newer technologies more rapidly.”


The seeds of language, teaching and learning were planted due to the demand for Oldowan tools, driving hominins to get better at communicating, and eventually allowing the advent of Acheulean hand-axes and cleavers some 1.7 million years ago.


Morgan said: “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’.”


Indeed, the data suggest that when the Oldowan stone-tool industry started, it was most likely not being taught, but communication methods to teach it were developed later.


Morgan continued: “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.”