Lexical Integration of Continuous Acoustic Detail: Normal and Impaired Listeners

描述(由申请人提供)：语音感知是将声音信号中的连续细节映射到离散的意义单元(如单词)的过程。考虑到信号的可变性和到达的速度，系统必须在很短的时间内处理大量的变化。这项研究的长期目标是了解这一过程是如何运作的。这项建议测试了现有工作的含义，表明词汇激活对信号中的连续细节和当前的口语识别模型敏感：在线词汇激活过程(快速并并行地工作以建立稳定的表征)可以随着时间的推移主动整合连续的细节，以预测即将到来的材料，解决过去的歧义，并组织感知过程。这将在基于视觉世界范式的四个系列行为实验中进行测试。在这个范例中，受试者在监控眼球运动的同时，听到仔细控制的口语，并在视觉环境中操纵物体。盯着每个物体的概率产生了随着时间的推移对该单词的激活(系统正在考虑该单词的程度)的逐时刻估计。前两个项目考察了未受损的听者的时间整合过程，以获得对语音修饰语音的感知和对说话速度的补偿。在每一篇文章中，我们将展示系统可以主动预测即将到来的材料和解决过去的歧义材料，并且这些过程受到词汇因素的调节。在第三个项目中，我们明确地测试了这个框架，考察了连续细节可以促进歧义解决的情况，但前提是它可以保持比已知的短期回声记忆存储操作更长的时间。这表明词汇过程在这种维持中起着独特的作用。第四个项目将这一框架应用于语言障碍，检验了与SLI相关的知觉缺陷起源于词汇过程而不是知觉过程的假设。最终，这个项目将有助于了解语言感知及其与语言障碍的关系的基本知识。由于感知能力和词汇能力通常在较高水平的语言之前发展，因此基于它们的诊断和治疗可能比其他技术更早应用(结果，也更成功)。因此，在此获得的基础知识可能有助于SLI的早期发现和治疗。

DESCRIPTION (provided by applicant): Speech perception is a process of mapping continuous detail in the acoustic signal onto discrete units of meaning like words. Given the variability in the signal and speed at which it arrives, the system must cope with a great deal of variation in a small amount of time. The long term objective of this research is to understand how this process works. This proposal tests an implication of existing work showing that lexical activation is sensitive to continuous detail in the signal and for current models of spoken word recognition: that online lexical-activation processes (which are fast and work in parallel to build stable representations) can actively integrate continuous detail over time to anticipate upcoming material, resolve ambiguity in the past, and organize perceptual processes. This will be tested in four series of behavioral experiments based on visual world paradigm. In this paradigm, subjects hear carefully controlled spoken language and manipulate objects in a visual environment while eye-movements are monitored. The probability of fixating each object yields a moment-by-moment estimate of the activation for that word (how much the system is considering that word) as it unfolds over time. The first two projects examine these temporal integration processes in unimpaired listeners for the perception of phonologically modified speech and compensation for speaking rate. In each we will show that system can actively anticipate upcoming material and resolve ambiguous material in the past and that these processes are modulated by lexical factors. In the third project we explicitly test this framework examining situations in which continuous detail could facilitate ambiguity resolution, but only if it can retained longer than short-term echoic memory stores are known to operate. This would suggest that lexical processes play a unique role in this maintenance. The fourth project applies this framework to language impairments, testing the hypothesis that perceptual deficits associated with SLI originate in lexical, not perceptual, processes. Ultimately this project will contribute to basic knowledge of speech perception and its relationship to language disorders. Since perceptual and lexical abilities typically develop before higher level language, diagnostics and therapies based on them may be applied earlier (and as a result, more successfully) than other techniques. Thus, the basic knowledge acquired here may contribute to earlier detection and treatment of SLI.