Evolution: Ancient tool makers and the evolution of language

Oldowan stone tool-making, which began approximately 2.5 million years ago, may have influenced the evolution of human language and teaching, reports a study published in Nature Communications this week. The authors suggest that a reliance on stone tool making by early hominins generated evolutionary selection for more advanced forms of transmitting knowledge.

Early hominins were skilled stone workers and were able to produce numerous sharp flakes from a single core of rock by striking it with a hammerstone (a process called knapping). It is evident from the remains of these tools that they were systematically produced, maintained and repaired, implying learning and practise. Whether Oldowan stone tool making has implications for the evolution of human language is debated however, as the apparent stasis in Oldowan technology, which persisted for more than 700,000 years, seems inconsistent with the presence of language.

Natalie Uomini, Thomas Morgan, Kevin Laland and colleagues conducted an experimental study to investigate the capability of five social learning mechanisms in the creation of Oldowan tools. In total, 184 participants took part, producing over 6,000 pieces of flint, each of which was weighed, measured and assessed for quality. By establishing the relative rates of transmission resulting from different means of communication they find that performance increases with teaching and, particularly, language. In contrast, there is little evidence that imitation/emulation enhances transmission. They suggest that this supports an account of human evolution in which reliance on Oldowan tools generated selection favouring teaching and, ultimately, language. The authors do note, however, that a longer learning period during experimentation may affect the capability of transmission methods.

The authors also suggest that Oldowan technology persisted due to poor social transmission mechanisms (in addition to other aspects of cognitive evolution) and that appearance of more advanced Acheulean tools, 1.7 million years ago, indicates the evolution of better transmission, such as a form of proto-language.