乳児の音声反応は,いかなる刺激条件下で発生が促進,抑制されるのか,どのような刺激条件下でどのような音声反応が発生するのかを発達とからませながら分析することが目的である。「喃語(他児)」,「泣声」,「あやし声+喃語」,「ニュース」,「あやし声(女)」,「あやし声(男)」,「喃語(本人)」の7種類の音声刺激を各1分間ずつテープレコーダーに録音し3〜12か月の乳児28名に再生して聞かせた。その結果,3〜6か月の乳児においては,「自分の喃語」の刺激呈示中に対する発声人数が「他人の喃語」に対するより有意に多く,特に「自分の喃語」の刺激にあたかもかけ合うかのように刺激の直後に発声しこのバターンの反応をくり返す現象がしばしば観察された。一方,刺激呈示後の「本人の喃語」に対する発声人数は「他人の喃語」に対する発声人数は他人の喃語に対する発声人数より有意に少なかった。「あやし声(女)」に対する発声人数は前期刺激呈示中に多いという点で「本人の喃語」と類似していた。このことから,乳児期前期においては聴覚的feed baek作用によるひとりしゃべりが多いこと,さらに母親の話しかけや世話と一連の関係があることが認められた。

The purpose of this article is to analyze the stimulus conditions under which the occurrence of the infant's speech sound response will be facilitated or inhibited, and the relation between the stimulus conditions and the types of speech sound responses, in connection with his development. "Other's babbllng sounds," "crying," "woman's fondling voice and babbling sounds," "newscaster's voice" , woman's fondling voice," "man's fonding voice " "his own babbling sounds," these seven kinds of sound stimuli were tape recorded respectively for a minute. Each of these tape recorded stimuli was played back and presented to 28 infants from 3 to 12 months. The results show the following. In infants 3 to 6 months. the number of the infants producing sounds in response to their own babbling sounds during the presentation of the stimulus is significantly greater than that of those responding to other's babbling sound. They produce sounds immediately after the sound stimulus especially in the way they exchange their sounds and the phenomenon of repeating this response pattern is often observed. On the other hand, the number of the infants producing sounds in response to their own babbling sounds after the presentation of the stimulus is significantly less than that of those responding to other's babbling sounds. The number of infants producing sounds in respond to woman's fondling voice is similar to that of those to their own babbling sounds, in the sense that it is great in the infants 3 to 6 months and during the presentation of stimu lus. It is recognized from these facts that in the early half of infancy, the infant often talks alone to himself through auditory feed-back process, and moreover it is connected with Mother's way of talking to the infant and caring for him.