Selection for Action: Interference Effects on the Articulation of Speech Sounds

言语产生是人类最基本的能力之一，它的崩溃可能会对个人造成毁灭性的后果。尽管如此，对于正常言语产生中涉及的认知和发音过程，或者这些过程可能因发育异常或脑损伤而受损的不同方式，还没有全面的理论。形成这样一个理论的一个困难是，两个广泛的处理水平的基础上的语音生产通常被视为在两个不同的学科。一方面，认知心理学家使用了一套方法来研究我们为想要发出的声音计算抽象代码的过程。另一方面，语音学家使用了另一套方法来研究我们如何将这种抽象的代码转化为产生声学信号的发音运动。我们的研究项目将这些学科结合在一起，以追求比迄今为止开发的更完整的言语产生理论。我们的研究项目的具体目标是确定信息如何在语音产生的这两个广泛的处理层次上流动。言语产生研究者通常假设这些处理水平之间的关系是“阶段性的”。从本质上说，这意味着他们已经假定，在运动系统开始计算与适当的发音运动相关的程序之前，必须完全计算出声音的抽象代码。认为这两个广泛的加工水平是在离散的阶段完成的观点，使研究人员能够将它们作为很大程度上独立的问题。然而，关于言语产生系统如何运作的这一基本假设从未被集中地检验过，事实上，最近的研究结果已经对这一假设提出了挑战。我们的研究将彻底测试这一核心假设，在一系列的几个实验中，使用我们实验室最近开发的创新的跨学科方法。该方法量化了被忽略的干扰音节的高度特定的影响（例如，KEY）对目标音节的发音（例如，核心）使用细粒度的发音和声学技术从实验语音学进口。我们的研究将询问是否，以及在什么样的实验环境下，视觉和听觉干扰音节留下系统的“痕迹”，否则准确的生产目标音节。这样的轨迹将表明，运动程序是自动计算的被忽略的干扰音节，并与运动程序的竞争与目标音节的发音。这些发现将挑战该领域大多数研究人员所假设的言语产生的阶段模型，因为在该模型上，关于未被选择用于产生的干扰物的信息不能传递到参与发音的运动系统。因此，这项研究项目的结果可能对我们理解言语产生的过程具有重要的理论意义。预计该项目中提出的创新方法将推动正常和受损语音产生科学研究的工具范围。

Speech production is one of the most fundamental of human abilities and its breakdown can have devastating consequences for individuals. Despite this, there is no comprehensive theory of the cognitive and articulatory processes involved in normal speech production or of the diverse ways in which these processes may be impaired through abnormal development or brain injury. One difficulty in formulating such a theory is that the two broad levels of processing underlying speech production have typically been treated within two distinct disciplines. On one side, cognitive psychologists have used one set of methods to study the processes through which we compute an abstract code for the sounds that we intend to produce. On the other side, phoneticians have used another set of methods to study how we translate this abstract code into the articulatory movements that produce an acoustic signal. Our research project brings these disciplines together in pursuit of a more complete theory of speech production than has so far been developed. The specific aim of our research project is to determine how information flows across these two broad levels of processing in speech production. Speech production researchers have generally made an assumption that the relationship between these levels of processing is 'staged'. Essentially, this means that they have assumed that an abstract code for sound must be computed fully before the motor system can begin to compute the programs associated with appropriate articulatory movement. The view that these two broad levels of processing are accomplished in discrete stages has allowed researchers to them as largely separate problems. However, this fundamental assumption about how the speech production system operates has never been tested in a concentrated manner, and in fact has been challenged by recent findings. Our research will test this core assumption thoroughly, in a series of several experiments that use an innovative interdisciplinary method recently developed in our laboratory. This method quantifies highly-specific influences of ignored distractor syllables (e.g., KEY) on the articulation of target syllables (e.g., CORE) using fine-grained articulatory and acoustic techniques imported from experimental phonetics. Our research will ask whether, and under which experimental circumstances, visual and auditory distractor syllables leave systematic 'traces' of themselves on the otherwise accurate production of target syllables. Such traces would indicate that motor programs are computed automatically for the ignored distractor syllables, and compete with the motor programs associated with the articulation of target syllables. These findings would challenge the staged model of speech production assumed by most researchers in the field, since on that model information about distractors not selected for production cannot be passed to the motor systems involved in articulation. The findings of this research project may therefore have major theoretical implications for our understanding of the processes underlying speech production. It is also expected that the innovative method advanced in this project will advance the range of tools available for the scientific study of normal and impaired speech production.