Doctoral Dissertation Research: Predictability and Recoverability of High Vowel Reduction in Speech

博士论文研究：语音中高元音减少的可预测性和可恢复性

• 批准号: 1524133
• 负责人: Lisa Davidson
• 金额: $ 1.08万
• 依托单位: New York University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524133&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Predictability; Recoverability

Human cognition relies on direct and indirect information to draw conclusions. Processes that rely on direct information are called bottom-up processes, where a conclusion is drawn based solely on the provided information; processes that rely on indirect information are called top-down processes, where elements such as context, pattern-recognition, and probability are used to form an expectation for a particular outcome. Studies have shown that a strong top-down process often blocks bottom-up processing of certain information available in the stimulus, but how the two types of processes interact is poorly understood. As an integral part of human cognition, language also shows interactions of top-down and bottom-up processes, where differences that are meaningful in one language may be readily ignored as uninformative in another. Language, therefore, is an excellent tool for shedding light on how the processing of direct and indirect information interacts in the mind.This research focuses on Japanese as a case study. The syllable structure of Japanese overwhelmingly follows a simple consonant-vowel structure. However, the process of high vowel reduction in Japanese, where unaccented vowels /i, u/ are weakened between two voiceless consonants (e.g., /suki/ [ski] 'like'), often results in the complete deletion of a vowel during speech production. However Japanese speakers often report perceiving a vowel between two consecutive voiceless consonants, even in the complete absence of a vowel (e.g., [ski] perceived as /suki/). It is unclear at this point what drives this misperception of apparently non-existent vowels, but there are two likely sources. The first is an indirect source. Given the simple syllable structure of Japanese, Japanese speakers are conditioned to expect a vowel after a consonant, in which case the misperception of a vowel would be the result of a strong top-down process. The alternative is a direct source. Because high vowel reduction is common in Japanese, Japanese speakers may be hypersensitive even to subtle acoustic information that indicates the presence of a vowel, in which case the perception of a vowel would be the result of a bottom-up process. A production experiment and a corpus study will first test what acoustic information for a weakened vowel exists in naturally produced speech. A perception experiment will then manipulate the direct and indirect information to test which of these Japanese listeners rely on more when perceiving a weakened vowel. The experimental results will inform a computational model, which investigates how a reliance on the direct and indirect cues might be learned. The experiments, together with the model, will lead to a deeper understanding of the extent in which bottom-up and top-down processes are shaped by experience both in language and more broadly in human cognition as a whole.

人类认知依赖于直接和间接的信息来得出结论。依赖于直接信息的过程被称为自下而上的过程，其中仅基于所提供的信息得出结论;依赖于间接信息的过程被称为自上而下的过程，其中使用诸如上下文，模式识别和概率等元素来形成对特定结果的期望。研究表明，一个强大的自上而下的过程往往会阻止自下而上处理刺激中的某些信息，但这两种类型的过程如何相互作用却知之甚少。作为人类认知的一个组成部分，语言也表现出自上而下和自下而上的过程的相互作用，其中在一种语言中有意义的差异在另一种语言中可能被忽视为无信息。因此，语言是一个很好的工具，揭示如何处理直接和间接信息在头脑中相互作用。日语的音节结构绝大多数遵循简单的辅音-元音结构。然而，日语中的高元音减少过程，其中非重读元音/i，u/在两个无重音辅音之间被削弱（例如，/suki/ [ski] 'like'），通常会导致在语音产生过程中完全删除元音。然而，日本人经常报告说，即使在完全没有元音的情况下，也会在两个连续的无元音辅音之间感知到元音（例如，[ski]被认为是/suki/）。目前还不清楚是什么导致了这种对显然不存在的元音的误解，但有两个可能的来源。第一个是间接来源。由于日语的音节结构简单，说日语的人习惯于在辅音之后期待元音，在这种情况下，对元音的误解将是一个强大的自上而下过程的结果。另一种是直接来源。由于高元音的减少在日语中很常见，所以日语使用者甚至可能对指示元音存在的细微声学信息过敏，在这种情况下，元音的感知将是自下而上过程的结果。一个生产实验和语料库研究将首先测试什么声学信息弱化元音存在于自然产生的语音。感知实验将操纵直接和间接信息，以测试这些日本听众在感知弱化元音时更依赖于哪一个。实验结果将为一个计算模型提供信息，该模型将研究如何学习对直接和间接线索的依赖。这些实验和模型将使我们更深入地理解自下而上和自上而下的过程在多大程度上受到语言和更广泛的人类认知经验的影响。