Research press release


Nature Communications

Evolution: Ancient tool makers and the evolution of language



今回、Natalie Uomini、Thomas Morgan、Kevin Lalandたちの研究グループは、実験的研究を行い、オルドヴァイ式石器の製作における5つの社会的学習メカニズムの能力を調べた。この研究には、合計184人が参加し、6000点以上の石器を製作した。それぞれの石器は、計量、計測され、品質評価も行われた。また、この研究チームは、情報伝達手段別に伝播率を調べた上で、指導方法の改善(特に言語の使用)に伴って石器作りの腕が上がったことを明らかにした。その一方で、まねや模倣によって伝播率が上昇することを示す証拠はほとんど得られなかった。Uominiたちは、オルドヴァイ式石器に対する依存によって「教えること」、そして究極的には言語に有利に働く選択が生じたとする人間の進化に関する学説が今回の研究によって裏付けられたという見解を示している。ただし、Uominiたちは、実験における学習期間を長くすると、伝達方法の能力が影響を受ける可能性も指摘している。


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.

doi: 10.1038/ncomms7029

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