Factors that facilitate perception of degraded speech and speech in noise

在日常生活中，人们经常在说话者或其他噪音干扰的背景下听到讲话。如果背景声音足够强烈，目标语音就会有效地退化，变得难以理解，以至于即使是最复杂的自动语音识别系统也会在很大程度上失败。然而，正常情况下，背景噪音水平相似的听力人类听众显然(具有欺骗性)很容易理解语言。人类善于利用他们的知识和经验来帮助他们解释含糊的语音信号。特别是，有意义的语义语境有助于年轻人和老年人理解口语句子，特别是在困难的听力条件下。虽然这项研究有很长的历史，但我们对语境效应的理解--它们何时出现以及它们影响理解的机制--是有限的。本文提出的工作将探索当言语难以理解时，限制信息(即有意义的语境)如何促进理解，要么是因为它以某种方式退化(例如，因为对话者有强烈的口音，或者因为语音是通过人工耳蜗被传递的)，要么是因为它被背景声音部分掩盖了。这项工作将有助于从理论上解释言语知觉中的语境效应。这一点很重要，因为在噪音中理解语音是老年人最常见的抱怨之一，到目前为止，研究重点是解释这个问题(与年龄相关的听力和认知变化)，从本质上讲，这个问题不容易补救。我实验室的研究是非常规的，因为它关注的是有助于成功感知言语的因素，以及这些因素可能会减轻听力损失的影响。其中最重要的一点是有效利用有意义的语境。随着人们年龄的增长和处理声音输入的保真度的下降，这种基于知识的语音理解线索变得越来越重要。对促进言语理解的因素有一个更全面的了解，这对优化这些因素和促进其使用是有帮助的。

In everyday life, speech is often heard against a background of interfering talkers or other noise. If the background sound is sufficiently intense, target speech is effectively degraded and becomes hard to understand, to the point that even the most sophisticated automatic speech recognition systems will largely fail. Nevertheless, normally hearing human listeners presented with similar levels of background noise understand speech with apparent (deceptive) ease. Humans are adept at using their knowledge and experience to help them interpret an ambiguous speech signal. In particular, meaningful semantic context facilitates comprehension of spoken sentences by young and older adults, especially in difficult listening conditions. Although this research has a long history, our understanding of contextual effects -- when they arise and the mechanisms by which they influence comprehension -- are limited. The work proposed here will explore how constraining information (i.e., meaningful context) facilitates comprehension when speech is difficult to understand, either because it is degraded in some way (e.g., because the interlocutor has a strong accent or the speech is transduced through a cochlear implant) or because it is partially masked by background sounds. This work will contribute fundamentally to a theoretical account of contextual effects in speech perception. This is important because understanding speech in noise is one of the most common complaints of older individuals, and research to date has focused on explanations of the problem (age-related changes in hearing and cognition) that, by their nature, are not easily remediable. Research in my lab is unconventional in its focus on factors that facilitate successful perception of speech and which may act to mitigate the effects of hearing loss. One of the most important of these is the effective use of meaningful context. As people age and the fidelity with which acoustic input is processed deteriorates, such knowledge-based cues to speech comprehension become increasingly important. A more complete understanding of the factors that can facilitate speech comprehension is instrumental to optimizing them and promoting their use.