Doctoral Dissertation Research: Perception of Japanese temporally-cued phonetic contrasts by Japanese and American English listeners: Behavioral and Electrophysiological Measures

这项研究将通过大脑和行为测量来研究美国听众如何感知日语单词中元音（例如kiro和kiiro）和辅音（例如kite和kitte）的持续时间差异。具体来说，这项研究将考察在没有接触过日语的情况下，说英语的美国人在区分日语中元音和辅音拉长的差异方面的能力。说美式英语和日语的人可能会关注不同的语音属性来识别日语单词，因为与英语不同，日语在单词层面上严重依赖音长来区分意思。本研究将从一个全新的方向来研究这个问题，将第一语言（L1）感知作为一种“过度学习”过程来考虑。“高度过度学习过程”干扰第二语言（L2）语音感知的概念与以下说法有关：在第一语言学习中，婴儿学会自动将注意力集中在单词识别所需的语音重要属性上（Jusczyk, 1997）。脑电测量，失配负性（MMN），将被用来比较两组听众对目标声音的预先注意、自动辨别和集中注意的辨别。研究表明，MMN是一种预先注意、自动歧视的指标。母语为美国英语的被试如果不仔细注意，可能无法区分日语中的长短音单词。相比之下，母语为日语的被试会在没有注意的情况下区分这些单词。单词的行为辨别（按下按钮听到声音变化）将进一步提供关于注意前大脑反应和需要注意的行为辨别之间关系的信息。该项目将深入了解参与者是如何自动辨别声音的，并通过大脑测量指标进行索引。此外，有关大脑反应和显性行为反应之间关系的信息将揭示潜在的大脑过程如何促进行为反应，并为了解日本声音系统的复杂性提供见解。这项研究的广泛影响包括几个方面。首先，该项目将允许开发基于证据的外语教育方法，这可以导致更像母语的语言感知和表达。其次，它将有助于双语教育领域（从婴儿到成人），并有助于确定第二语言语言感知技能应该引入的关键时期。第三，因为它将改善目前的外语教学方法，它将通过提高第二语言学习者的沟通能力来造福社会。

This study will examine how American listeners perceive differences in duration of vowels (e.g., kiro vs. kiiro) and consonants (e.g., kite vs. kitte) in Japanese words using brain and behavioral measures. Specifically, the study will examine how well American English speakers, with no previous exposure to Japanese, can distinguish differences in vowel and consonant lengthening in Japanese. American English and Japanese speakers are likely to focus on different speech sound properties to recognize Japanese words because, unlike English, Japanese relies heavily on sound duration to distinguish meaning at the word level. This study will examine the question from a novel direction by considering the implications of first-language (L1) perception as an "over-learned" process. The notion of "highly over-learned processes" interfering with second-language (L2) speech perception relates to the claim that in first language learning, infants learn to automatically focus attention on important properties of speech sounds needed for word recognition (Jusczyk, 1997). The brain electrical measure, Mismatch Negativity (MMN), will be used to compare pre-attentive, automatic discrimination of the target sounds to discrimination with focused attention in the two groups of listeners. Research indicates that MMN serves as an index of pre-attentive, automatic discrimination. Subjects whose L1 is American English may not be able to discriminate between words with short and long sounds in Japanese without careful attention. In contrast, subjects whose L1 is Japanese will discriminate between these words without attention as shown by MMN. Behavioral discrimination of the words (pressing a button to a sound change) will provide further information regarding the relationship between preattentive brain responses and behavioral discrimination, which requires attention. The project will provide insight into how participants discriminate sounds automatically, as indexed by brain measures. In addition, information concerning the relationship between brain responses and overt behavioral responses will reveal how underlying brain processes contribute to the behavioral response and provide insight into the intricacies of the Japanese sound system. The broader impact of this research include several areas. First, the project will allow for development of evidence-based methods of foreign language education that can lead to more native-like speech perception and production. Second, it will contribute to the bilingual education field (infants through adults) and help determine critical periods in which speech perception skills in L2 should be introduced. Third, because it will improve the current approach to foreign language instruction, it will benefit society by improving the communication abilities of L2 learners.