Lexical Integration of Continuous Acoustic Detail: Normal and Impaired Listeners

描述（由申请人提供）：语音感知是将声学信号中的连续细节映射到离散的意义单元（如单词）上的过程。考虑到信号的可变性及其到达的速度，系统必须在很短的时间内科普大量的变化。这项研究的长期目标是了解这个过程是如何工作的。该提案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口语识别模型敏感：在线词汇激活过程（快速且并行工作以构建稳定的表征）可以随着时间的推移积极整合连续细节，以预测即将到来的材料，解决过去的歧义，并组织感知过程。这将被测试在四个系列的行为实验的基础上的视觉世界范式。在这个范例中，受试者仔细地听到控制的口语，并在视觉环境中操纵物体，同时监视眼球运动。注视每个物体的概率产生了对该单词随时间展开的激活的每时每刻的估计（系统考虑该单词的程度）。前两个项目检查这些时间整合过程中未受损的听众的感知语音修改的讲话和补偿说话的速度。在每一个，我们将表明，系统可以积极地预测即将到来的材料和解决过去的歧义材料，这些过程是由词汇因素调制。在第三个项目中，我们明确地测试这个框架检查的情况下，连续的细节可以促进歧义的解决方案，但只有当它可以保留更长的时间比短期回声记忆存储已知的操作。这表明，词汇过程在这种维持中发挥着独特的作用。第四个项目将此框架应用于语言障碍，测试与SLI相关的感知缺陷起源于词汇，而不是感知过程的假设。最终，这个项目将有助于言语感知的基本知识及其与语言障碍的关系。由于感知和词汇能力通常在高级语言之前发展，因此基于它们的诊断和治疗可能比其他技术更早（因此，更成功）。因此，这里获得的基本知识可能有助于早期发现和治疗SLI。

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.