Investigating the mechanisms of poor accent adaptation in healthy older adults

摘要 不熟悉的口音对老年人的理解造成了很大的障碍，而且还不够 有证据可以简单地将其归因于与年龄相关的听力或认知功能下降。作为 近年来，美国65岁及以上的成年人人口急剧增长，至关重要的是 已经开发了干预措施来改善口音适应，但目前还没有这样的事情存在。在这项提案中，我们 考察泛化是老年人口音适应问题的根源这一假设； 具体地说，老年人可能能够充分暴露在有口音的人身上，但不能正确地适应 将这些信息应用于将来遇到口音相同的说话者。这一观点是 受理想适配器模型的启发，提出了一种语音感知的计算框架 听者独立地跟踪语音信号被说话者的不同品质改变的方式，例如 年龄、性别或口音，并在适应不熟悉的谈话者时使用这些信息。在过去的几年中 行为实验，我们将比较年轻人和老年人对口音信息的概括 爱说话的人。在实验1A和1B中，年轻人(18-22岁)和老年人(65岁以上)将参与词汇- 引导式知觉学习(LGPL)任务，这是一种成熟的口音适应范式，我们将对其进行修改以 使之更适合于评估泛化，例如在每个刺激中增加一个载体句子 让听者更多地接触到口音。两个年龄组之间的表现将是 相比之下，预计老年人将无法将语音信息概括为一个新的说话者 同样的口音。在实验2中，年长的成年人将听一个用人造口音说的故事， 反映了自然主义的听力条件，这既增加了认知需求，也允许使用更多 自上而下的启发式算法。在实验1B和实验1B中，老年人在LGPL任务中的概化程度 然后对实验2中的故事听力任务进行比较。在实验3中，我们将使用理想适配器 模型试图指明导致老年人泛化功能受损的机制。我们将创造 作为与年龄相关的感觉/认知障碍的替代物的模型的几个扰动，如 听力损失或处理速度变慢，以及更多的概念性障碍，如 以前的经验。然后，模型的输出将与老年人的表现进行比较，以做出判断 哪种扰动最能反映人类数据。这一提议将使我们对 老年人的口音适应，这反过来可以被临床医生用来更好地定制干预措施 未来。此外，它将为申请人提供以下方面的培训机会：(1)将我的研究扩展到 健康的老年人，(2)将计算建模集成到我的研究计划中，以及(3)与 跨学科的老龄化研究人员，目的是利用这些来建立一个研究计划，如 申请者在作为研究人员的职业生涯中走向独立。

ABSTRACT Unfamiliar accented speech poses a significant barrier comprehension in older adults, and there is insufficient evidence to attribute it simply to age-related declines in hearing acuity or cognitive functioning. As the population of adults 65 and older in the US has grown dramatically in recent years, it is critical that interventions be developed to improve accent adaptation, but no such thing yet exists. In this proposal, we examine the hypothesis that generalization lays at the root of older adults’ issues with accent adaptation; specifically, older adults may be able to adapt to an accented talker with sufficient exposure, but fail to properly apply this information to future encounters with talkers who share the same accent. This perspective is informed by the Ideal Adapter model, a computational framework for speech perception wherein it is proposed that listeners independently track the way the speech signal is altered by different qualities of the talker, like age, sex, or accent, and use that information when adapting to an unfamiliar talker. Over the course of several behavioral experiments, we will compare younger and older adults’ generalization of accent information across talkers. In Experiments 1A & 1B, younger (18-22 years) and older adults (65+ years) will engage in lexically- guided perceptual learning (LGPL) task, a well-established, accent adaptation paradigm that we will modify to make more suitable for assessing generalization, such as adding a carrier sentence to each stimulus to provide the listener with more exposure to the accent. Performance between the two age groups will be compared, with the expectation that older adults will fail to generalize phonetic information to a novel talker of the same accent. In Experiment 2, older adults will listen to a story spoken with an artificial accent which better reflects naturalistic listening conditions, which both adds cognitive demands but also allows for the use of more top-down heuristics. The magnitude of generalization in older adults on the LGPL task in Experiment 1B and the story-listening task in Experiment 2 will then be compared. In Experiment 3, we will use the Ideal Adapter model to attempt to specify the mechanism that leads to impaired generalization in older adults. We will create several perturbations to the model that serve as proxies for age-related sensory/cognitive impairments like hearing loss or slower processing speed, as well as more conceptual impairments like the downweighing of previous experience. Output from the model will then be compared to older adults’ performance to adjudicate which perturbation best reflects human data. This proposal will yield novel insight into the mechanisms of accent adaptation in older adults, which in turn can be used by clinicians to better tailor interventions in the future. In addition, it will provide the applicant with training opportunities in (1) expanding my research into healthy older adults, (2) integrating computational modeling into my research program, and (3) networking with interdisciplinary researchers of aging, with the intention of utilizing these to establish a research program as the applicant moves towards independence in career as a researcher.