Yeung H Henny, Werker Janet F
Department of Psychology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
Cognition. 2009 Nov;113(2):234-43. doi: 10.1016/j.cognition.2009.08.010. Epub 2009 Sep 17.
One of the central themes in the study of language acquisition is the gap between the linguistic knowledge that learners demonstrate, and the apparent inadequacy of linguistic input to support induction of this knowledge. One of the first linguistic abilities in the course of development to exemplify this problem is in speech perception: specifically, learning the sound system of one's native language. Native-language sound systems are defined by meaningful contrasts among words in a language, yet infants learn these sound patterns before any significant numbers of words are acquired. Previous approaches to this learning problem have suggested that infants can learn phonetic categories from statistical analysis of auditory input, without regard to word referents. Experimental evidence presented here suggests instead that young infants can use visual cues present in word-labeling situations to categorize phonetic information. In Experiment 1, 9-month-old English-learning infants failed to discriminate two non-native phonetic categories, establishing baseline performance in a perceptual discrimination task. In Experiment 2, these infants succeeded at discrimination after watching contrasting visual cues (i.e., videos of two novel objects) paired consistently with the two non-native phonetic categories. In Experiment 3, these infants failed at discrimination after watching the same visual cues, but paired inconsistently with the two phonetic categories. At an age before which memory of word labels is demonstrated in the laboratory, 9-month-old infants use contrastive pairings between objects and sounds to influence their phonetic sensitivity. Phonetic learning may have a more functional basis than previous statistical learning mechanisms assume: infants may use cross-modal associations inherent in social contexts to learn native-language phonetic categories.
语言习得研究的核心主题之一是学习者所展示的语言知识与支持这种知识归纳的语言输入明显不足之间的差距。在发展过程中最早体现这一问题的语言能力之一是语音感知：具体来说，就是学习母语的语音系统。母语的语音系统是由一种语言中单词之间有意义的对比来定义的，然而婴儿在习得大量单词之前就学会了这些语音模式。以往针对这个学习问题的方法表明，婴儿可以通过对听觉输入的统计分析来学习语音类别，而不考虑单词的指代对象。这里给出的实验证据却表明，幼儿可以利用单词标注情境中出现的视觉线索来对语音信息进行分类。在实验1中，9个月大正在学习英语的婴儿无法区分两种非母语语音类别，从而在感知辨别任务中建立了基线表现。在实验2中，这些婴儿在观看了与两种非母语语音类别始终配对的对比视觉线索（即两个新奇物体的视频）后成功完成了辨别。在实验3中，这些婴儿在观看了相同的视觉线索但与两种语音类别不一致配对后，辨别失败。在实验室中证明存在单词标签记忆之前的年龄阶段，9个月大的婴儿利用物体和声音之间的对比配对来影响他们的语音敏感度。语音学习可能具有比以往统计学习机制所假设的更具功能性的基础：婴儿可能利用社会情境中固有的跨模态关联来学习母语语音类别。
