野生のチンパンジーのコミュニケーションに見られる構造化された音声シーケンスの証拠が、ヒトの言語進化に洞察を与える Evidence of structured vocal sequences in wild chimpanzee communication provides insights into human language evolution
2022-05-16 マックス・プランク研究所
チンパンジーは最大10種類の鳴き声を含む数百種類の発声系列を作り出していることがわかりました。また、これらの発声の順序は一定の規則に従っており、発声は構造化された形で互いに関連付けされていた。
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チンパンジーは秩序と組み換えの特性を持つ多様な音声系列を生成する Chimpanzees produce diverse vocal sequences with ordered and recombinatorial properties
Cédric Girard-Buttoz,Emiliano Zaccarella,Tatiana Bortolato,Angela D. Friederici,Roman M. Wittig & Catherine Crockford
Communications Biology Published:16 May 2022
DOI:https://doi.org/10.1038/s42003-022-03350-8
Abstract
The origins of human language remains a major question in evolutionary science. Unique to human language is the capacity to flexibly recombine a limited sound set into words and hierarchical sequences, generating endlessly new sentences. In contrast, sequence production of other animals appears limited, stunting meaning generation potential. However, studies have rarely quantified flexibility and structure of vocal sequence production across the whole repertoire. Here, we used such an approach to examine the structure of vocal sequences in chimpanzees, known to combine calls used singly into longer sequences. Focusing on the structure of vocal sequences, we analysed 4826 recordings of 46 wild adult chimpanzees from Taï National Park. Chimpanzees produced 390 unique vocal sequences. Most vocal units emitted singly were also emitted in two-unit sequences (bigrams), which in turn were embedded into three-unit sequences (trigrams). Bigrams showed positional and transitional regularities within trigrams with certain bigrams predictably occurring in either head or tail positions in trigrams, and predictably co-occurring with specific other units. From a purely structural perspective, the capacity to organize single units into structured sequences offers a versatile system potentially suitable for expansive meaning generation. Further research must show to what extent these structural sequences signal predictable meanings.
