Department of Linguistics, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom.
Speech, Hearing and Phonetic Sciences, University College London, Chandler House, 2 Wakefield Street, London, WC1N 1PF, United Kingdom.
Sci Rep. 2019 Dec 20;9(1):19592. doi: 10.1038/s41598-019-55085-y.
This study measured infants' neural responses for spectral changes between all pairs of a set of English vowels. In contrast to previous methods that only allow for the assessment of a few phonetic contrasts, we present a new method that allows us to assess changes in spectral sensitivity across the entire vowel space and create two-dimensional perceptual maps of the infants' vowel development. Infants aged four to eleven months were played long series of concatenated vowels, and the neural response to each vowel change was assessed using the Acoustic Change Complex (ACC) from EEG recordings. The results demonstrated that the youngest infants' responses more closely reflected the acoustic differences between the vowel pairs and reflected higher weight to first-formant variation. Older infants had less acoustically driven responses that seemed a result of selective increases in sensitivity for phonetically similar vowels. The results suggest that phonetic development may involve a perceptual warping for confusable vowels rather than uniform learning, as well as an overall increasing sensitivity to higher-frequency acoustic information.
本研究测量了婴儿对一组英语元音之间所有对的频谱变化的神经反应。与之前只允许评估少数语音对比的方法不同，我们提出了一种新的方法，允许我们评估整个元音空间的光谱灵敏度变化，并为婴儿的元音发展创建二维感知图。年龄在 4 到 11 个月的婴儿被播放了一系列串联元音，使用脑电图记录中的听觉变化复合 (ACC) 评估了每个元音变化的神经反应。结果表明，最小的婴儿的反应更能反映元音对之间的声学差异，并反映出对第一共振峰变化的更高权重。年龄较大的婴儿的反应较少受声学驱动，这似乎是对语音相似的元音的敏感性选择性增加的结果。研究结果表明，语音发展可能涉及对易混淆元音的感知扭曲，而不是统一学习，以及对更高频率声学信息的整体敏感性增加。
