Zhao Liming, Lian Miaoqing
Key Research Base of Humanities and Social Sciences of the Ministry of Education, Academy of Psychology and Behavior, Tianjin Normal University, Tianjin, China.
Faculty of Psychology, Tianjin Normal University, Tianjin, China.
Front Psychol. 2021 Feb 23;12:581304. doi: 10.3389/fpsyg.2021.581304. eCollection 2021.
Developmental stuttering is a widely discussed speech fluency disorder. Research on its mechanism has focused on an atypical interface between the planning (PLAN) and execution (EX) processes, known collectively as the EXPLAN model. However, it remains unclear how this atypical interface influences people who stutter. A straightforward assumption is that stuttering speakers adopt a smaller scope of speech planning, whereas a defect in word retrieval can be confounding. To shed light on this issue, we took the semantic blocking effect as an index to examine lexical planning in word and phrase production. In Experiment 1, for word production, pictures from the same semantic category were combined to form homogeneous blocks, and pictures from different categories were combined to form heterogeneous blocks. A typical effect of semantic blocking showing longer naming latencies for homogeneous blocks than heterogeneous ones was observed for both stuttering and fluent speakers. However, this effect was smaller for stuttering speakers, when it was subject to lexical defects in stuttering. In Experiment 2, for a conjoined noun phrase production task, the pictures referring to the first noun were manipulated into homogeneous and heterogeneous conditions. The semantic blocking effect was also much smaller for stuttering speakers, indicating a smaller scope of lexical planning. Therefore, the results provided more evidence in support of the EXPLAN model and indicated that a smaller scope of lexical planning rather than lexical defects causes the atypical interface for stuttering. Moreover, a comparison between these two tasks showed that the study findings have implications for syntactic defects in stuttering.
发育性口吃是一种被广泛讨论的言语流畅性障碍。对其机制的研究集中在计划（PLAN）和执行（EX）过程之间的非典型接口上，这两个过程统称为EXPLAN模型。然而，目前尚不清楚这种非典型接口如何影响口吃者。一个直接的假设是，口吃者采用的言语计划范围较小，而词汇检索缺陷可能会造成混淆。为了阐明这个问题，我们以语义阻塞效应为指标，研究单词和短语生成中的词汇计划。在实验1中，对于单词生成，将来自相同语义类别的图片组合成同质块，将来自不同类别的图片组合成异质块。对于口吃者和流利说话者，都观察到了语义阻塞的典型效应，即同质块的命名潜伏期比异质块长。然而，由于口吃者存在词汇缺陷，这种效应在口吃者中较小。在实验2中，对于联合名词短语生成任务，将指代第一个名词的图片处理成同质和异质条件。口吃者的语义阻塞效应也小得多，表明词汇计划范围较小。因此，这些结果为支持EXPLAN模型提供了更多证据，并表明词汇计划范围较小而非词汇缺陷导致了口吃的非典型接口。此外，这两项任务之间的比较表明，研究结果对口吃的句法缺陷具有启示意义。
