Mechanisms of adaptation in (healthy and aphasic) noisy-channel comprehension

拟议的研究和培训的广泛目标是了解 有效的语言理解以及语言障碍患者的语言理解是如何改变的， 尤其是失语症。最近的语言处理理论提出，交流通常是 易受噪声影响(例如，Gibson、Bergen和Piantadosi，2013)--以扬声器错误、环境噪声、 或听者的误解--理解者使用先验知识和噪音的合理整合 推断损坏消息的预期含义的证据。此外，吉布森、桑德伯格、费多连科， Bergen和Kiran(在出版中)提出，未能使用句法线索和过度依赖似是而非 由失语症患者提供的信息可以通过相同的噪声通道框架来解释， 而不是句法缺陷。因此，失语症患者的基本噪音水平更高 在它们表示消息可能如何被破坏时。这些新颖的建议提出了重要的 关于健康人和失语症患者语言处理的问题。建议数 这项工作将研究支持噪音模型表示的学习和记忆机制。 目标1.确定听者是否适应噪声的特定属性，以及适应程度 表现形式与它们所经历的背景相联系。 目的2.研究噪声的表征和适应机制是否存在差异 健康人和失语症患者。 在拟议的实验中，我们将通过比较有语法障碍的人来解决这些目标 失语症适用于神经学健康的对照组和脑损伤的对照组。参与者将接触到 句子，其中一些包含错误(即，噪音)，并要求解释它们的意思。关键人物 句子在语法上是正确的，但基于世界知识是不可信的(例如“这位母亲给了孩子 用蜡烛点燃女儿。“)。如果参与者认为原定的句子实际上是，“母亲给了 蜡烛献给女儿“，这表明，在他们的噪音模型中，很可能会删除一个单词。 将以各种方式操纵噪音，以测试参与者是否能够学习 噪声(例如，某些错误比其他错误更有可能)，将噪声的特征绑定到上下文(例如， 一些错误更有可能发生，但仅限于特定的说话者)，或者灵活地控制自己的错误 适应(例如，如果他们被告知说话人的错误是由于外部原因，调整他们的期望 已被移除的干扰)。这项研究的发现将使我们更接近理解 语言处理系统是如何在健康的个体中完成如此高效的交流的 可变噪音的脸。此外，了解这些噪声适应机制是如何在 失语症将有助于发展失语症患者的治疗方法。

The broad objective of the proposed research and training is to understand the mechanisms that underlie efficient language comprehension and how these are altered in persons with language impairment, specifically aphasia. Recent theories of language processing have proposed that communication is typically subject to noise (e.g., Gibson, Bergen, & Piantadosi, 2013)—in the form of speaker error, environmental noise, or listener misperception—and that comprehenders employ rational integration of prior knowledge and noisy evidence to infer the intended meaning of the corrupted message. Further, Gibson, Sandberg, Fedorenko, Bergen, & Kiran (in press) propose that failures to use syntactic cues and an over-reliance on plausibility information by persons with agrammatic aphasia can be explained by the same noisy-channel framework, rather than a syntactic deficit. On this account, persons with aphasia simply have a higher base level of noise in their representation of how a message is likely to be corrupted. These novel proposals raise important questions about language processing in healthy individuals, as well as persons with aphasia. The proposed work will examine the learning and memory mechanisms that support the representation of the noise model. Aim 1. To determine whether listeners adapt to specific properties of the noise and to what extent the representations are tied to the context in which they are experienced. Aim 2. To investigate whether the representation of noise and adaptation mechanisms differ between healthy individuals and persons with agrammatic aphasia. In the proposed experiments, we will address these aims by comparing persons with agrammatic aphasia to neurologically healthy controls and brain damaged controls. Participants will be exposed to sentences, some of which contain errors (i.e., noise), and asked to interpret their meaning. The critical sentences will be grammatically correct but implausible based on world knowledge (e.g. “The mother gave the candle the daughter.”). If participants assume the intended sentence was actually, “The mother gave the candle to the daughter,” that indicates that, in their model of the noise, the deletion of one word is very likely. The noise will be manipulated in various ways to test whether participants can learn specific features of the noise (e.g., that some errors are more likely than others), bind features of the noise to the context (e.g., that some errors are more likely but only given a particular speaker), or flexibly exert control over their own adaptation (e.g., adjust their expectations if they are told the speaker's errors were due to an external disturbance that has been removed). Findings from this research will bring us one step closer to understanding how the language processing system, in healthy individuals, accomplishes such efficient communication in the face of variable noise. Furthermore, understanding how these noise-adaptation mechanisms operate in aphasia will contribute to the development of treatments for persons with aphasia.