Dial Heather R, McMurray Bob, Martin Randi C
Department of Communication Sciences and Disorders, University of Texas at Austin, 2504A Whitis Avenue (A1100), 4th Floor CMA, Austin, TX, 78712-0114, USA.
Department of Psychological and Brain Sciences, Department of Communication Sciences and Disorders, Department of Linguistics, Department of Otolaryngology, University of Iowa, Iowa City, IA, USA.
Atten Percept Psychophys. 2019 May;81(4):1047-1064. doi: 10.3758/s13414-019-01718-3.
Some early studies of people with aphasia reported strikingly better performance on lexical than on sublexical speech perception tasks. These findings challenged the claim that lexical processing depends on sublexical processing and suggested that acoustic information could be mapped directly to lexical representations. However, Dial and Martin (Neuropsychologia 96: 192-212, 2017) argued that these studies failed to match the discriminability of targets and distractors for the sublexical and lexical stimuli and showed that when using closely matched tasks with natural speech tokens, no patient performed substantially better at the lexical than at the sublexical processing task. In the current study, we sought to provide converging evidence for the dependence of lexical on sublexical processing by examining the perception of synthetic speech stimuli varied on a voice-onset time continuum using eye-tracking methodology, which is sensitive to online speech perception processes. Eight individuals with aphasia and ten age-matched controls completed two visual world paradigm tasks: phoneme (sublexical) and word (lexical) identification. For both identification and eye-movement data, strong correlations were observed between the sublexical and lexical tasks. Critically, no patient within the control range on the lexical task was impaired on the sublexical task. Overall, the current study supports the claim that lexical processing depends on sublexical processing. Implications for inferring deficits in people with aphasia and the use of sublexical tasks to assess sublexical processing are also discussed.
一些针对失语症患者的早期研究报告称，在词汇语音感知任务上的表现明显优于次词汇语音感知任务。这些发现挑战了词汇加工依赖于次词汇加工的观点，并表明声学信息可以直接映射到词汇表征。然而，戴尔和马丁（《神经心理学》96: 192 - 212, 2017）认为，这些研究未能使次词汇和词汇刺激的目标与干扰项的可辨别性相匹配，并表明当使用与自然语音片段紧密匹配的任务时，没有患者在词汇加工任务上的表现显著优于次词汇加工任务。在本研究中，我们试图通过使用对在线语音感知过程敏感的眼动追踪方法，检查在语音起始时间连续体上变化的合成语音刺激的感知，为词汇加工依赖于次词汇加工提供趋同证据。八名失语症患者和十名年龄匹配的对照组完成了两项视觉世界范式任务：音素（次词汇）和单词（词汇）识别。对于识别和眼动数据，在次词汇和词汇任务之间观察到了强相关性。关键的是，在词汇任务处于控制范围内的患者在次词汇任务上没有受损。总体而言，本研究支持词汇加工依赖于次词汇加工这一观点。还讨论了对推断失语症患者缺陷以及使用次词汇任务评估次词汇加工的影响。
