Speech Perception under Cognitive Load

认知负荷下的言语感知

• 批准号: ES/R004722/1
• 负责人: Sven Mattys
• 金额: $ 36.25万
• 依托单位: University of York
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ES%2FR004722%2F1
• 关键词: Speech; Perception; under; Cognitive; Load

Most theories of human speech perception are derived from tasks performed in a quiet environment and under conditions of undivided attention. However, in the past few years, there has been a surge of interest in modelling speech recognition in more realistic conditions (e.g., noisy background, accented speech). However, among these realistic conditions, those resulting from a cognitive load have received little attention. Here, we define cognitive load (CL) as any listening challenges arising not from a distortion of the speech signal but from the recruitment of processing resources due to concurrent attentional or mnemonic demands. For example, what are the consequences of monitoring cockpit instruments on a pilot's ability to follow spoken instructions from ground control? The disruptive effect of CL on speech perception is noticed as early as in the initial stages of acoustic encoding. Under some circumstances, CL can even lead to a form of transient hearing impairment called inattentional deafness. Despite the obvious implications that these results have for theory and clinical practice, little is known about the low-level mechanisms by which CL interferes with speech perception. The aim of this proposal is to address this issue in three interconnected research streams drawing upon psychometric and identification paradigms.The first stream asks whether CL affects all acoustic dimensions of speech equally. This question is important because not all acoustic dimensions are equally crucial for communication. For example, successful word recognition is more resilient to pitch distortions than duration distortions. The idea that CL affects some dimensions more than others is motivated by the claim that CL (e.g., a concurrent visual task) causes listeners to rapidly shift attention back and forth between the speech signal and the CL task, leading to an underestimation of the duration of the speech signal. If this hypothesis is correct, CL should lead primarily to a distortion of auditory temporal judgements and leave other core dimensions (loudness, pitch, and spectral structure) unaffected. This will be contrasted with the claim that CL leads to a general reduction in auditory precision across all acoustic dimensions.The second stream investigates whether the format of the CL stimuli affects the severity of the CL interference. For example, is speech perception more affected by a concurrent task that requires rehearsing words silently (phonological format) or by a task that requires processing visual stimuli (visual format)? These experiments will address the debate between modal and amodal views of the processing resources used during speech perception. The third stream aims to distinguish two potential mechanisms behind CL interference: Encoding and maintenance. Encoding is the process of converting a sensory input into mental representations. Maintenance is the process of preserving these representations in memory. Encoding of the CL stimuli will be manipulated such that it takes place either during or before the speech stimuli, hence pitting encoding against maintenance as the mechanism underlying interference. An encoding hypothesis predicts that only simultaneous encoding of speech and CL stimuli should lead to CL effects. In order to explore the generalisability of the above phenomena beyond the speech domain, the effect of CL will be tested on both speech and non-speech sounds. This comparison will situate our findings within the long-standing debate on the existence of a specialised speech mode for sound perception.Finally, because the notion of "cognitive listening" is becoming central not only in speech research but also in hearing practice, we will engage with clinical audiologists and discuss ways of including a cognitive component into standard pure-tone audiometric (PTA) and advise on potential phase-II clinical trials.

大多数人类言语感知的理论都来自于在安静的环境和集中注意力的条件下执行的任务。然而，在过去几年中，人们对在更现实的条件下（例如，嘈杂的背景、带口音的语音）。然而，在这些现实条件中，那些由认知负荷引起的很少受到关注。在这里，我们将认知负荷（CL）定义为任何听力挑战，而不是从语音信号的失真，但从招聘的处理资源，由于并发的注意力或记忆的需求。例如，监控驾驶舱仪表对飞行员遵循地面控制口头指令的能力有什么影响？CL对言语感知的破坏性影响早在声学编码的初始阶段就已被注意到。在某些情况下，CL甚至会导致一种称为无意性耳聋的短暂性听力障碍。尽管这些结果对理论和临床实践有明显的影响，但对CL干扰言语感知的低水平机制知之甚少。这个建议的目的是解决这个问题，在三个相互关联的研究流借鉴心理测量和识别paradigm. First流问CL是否影响所有的语音声学尺寸同样。这个问题很重要，因为并非所有的声学维度对通信都同样重要。例如，成功的单词识别对音调失真的弹性比持续时间失真更大。CL对某些维度的影响大于其他维度的想法是由CL（例如，并发的视觉任务）使听者在语音信号和CL任务之间快速地来回转移注意力，导致对语音信号的持续时间的低估。如果这个假设是正确的，CL应该主要导致听觉时间判断的失真，而不影响其他核心维度（响度，音高和频谱结构）。这将与CL导致听觉精度在所有声学dimensions. Second流中普遍降低的说法形成对比，研究CL刺激的格式是否影响CL干扰的严重程度。例如，语音感知是否更容易受到同时进行的任务的影响，即需要安静地排练单词（语音格式）或需要处理视觉刺激（视觉格式）的任务？这些实验将解决言语感知过程中使用的处理资源的模态和非模态观点之间的争论。第三个流程旨在区分CL干扰背后的两种潜在机制：编码和维护。编码是将感官输入转换为心理表征的过程。维护是将这些表示保存在内存中的过程。CL刺激的编码将被操纵，使得它发生在语音刺激期间或之前，因此使编码对抗作为干扰基础的机制的维护。编码假说预测，只有同时编码的语音和CL刺激应导致CL效果。为了探索上述现象在语音领域之外的普遍性，将在语音和非语音声音上测试CL的效果。这种比较将在长期的争论中证实我们的发现，即是否存在一种专门的语音模式来感知声音。最后，由于“认知听力”的概念不仅在语音研究中，而且在听力实践中越来越重要，我们将与临床听力学家合作，讨论将认知成分纳入标准纯音听力（PTA）的方法，并就潜在阶段提供建议-II临床试验。