チンパンジーの聴覚と音声 : 言語の起源と進化(1999年度 第1回フォーラム ことばの発達と異常)

抄録

In order to understand the biological bases of language, basic auditory functions, the perception of human speech sounds and species-specific vocal sounds was investigated in the chimpanzee. It was found that chimpanzees have a W-shaped auditory sensitivity curve which is similar to monkeys. They were sensitive to the first formant and the lower harmonic sounds of human vowels and vowel-like vocal sounds (grunts). Phenomenon of vocal tract normalization, the magnet effect, categorical perception and the context effect was reported. Early vocal development was also examined. It was found that chimpanzees and humans share the first two stages of the five stages of human vocal development, that is, the phonation and goo stages, but the chimpanzee infant did not pass the expansion stage and did not reach the canonical bubbling stages. It was suggested that it is difficult for the chimpanzee to have spoken language.