Department of Speech, Language, and Hearing Sciences, Boston University, United States.
Department of Speech, Language, and Hearing Sciences, Boston University, United States.
Brain Lang. 2021 Oct;221:104996. doi: 10.1016/j.bandl.2021.104996. Epub 2021 Aug 3.
Speech is processed less efficiently from discontinuous, mixed talkers than one consistent talker, but little is known about the neural mechanisms for processing talker variability. Here, we measured psychophysiological responses to talker variability using electroencephalography (EEG) and pupillometry while listeners performed a delayed recall of digit span task. Listeners heard and recalled seven-digit sequences with both talker (single- vs. mixed-talker digits) and temporal (0- vs. 500-ms inter-digit intervals) discontinuities. Talker discontinuity reduced serial recall accuracy. Both talker and temporal discontinuities elicited P3a-like neural evoked response, while rapid processing of mixed-talkers' speech led to increased phasic pupil dilation. Furthermore, mixed-talkers' speech produced less alpha oscillatory power during working memory maintenance, but not during speech encoding. Overall, these results are consistent with an auditory attention and streaming framework in which talker discontinuity leads to involuntary, stimulus-driven attentional reorientation to novel speech sources, resulting in the processing interference classically associated with talker variability.
说话人不连续且混合时，语言处理的效率低于单一说话人，但人们对处理说话人变化的神经机制知之甚少。在这里，我们使用脑电图 (EEG) 和瞳孔测量法来测量对说话人变化的心理生理反应，同时让听众执行数字跨度任务的延迟回忆。听众听到并回忆了具有说话人（单说话人与混合说话人数字）和时间（0 与 500 毫秒的数字间间隔）不连续的七位数序列。说话人不连续性降低了序列回忆的准确性。说话人不连续和时间不连续都引起了类似于 P3a 的神经诱发反应，而快速处理混合说话人的语音导致了瞳孔的相位扩张增加。此外，混合说话者的语音在工作记忆维持期间产生的 alpha 振荡功率较小，但在语音编码期间没有。总的来说，这些结果与听觉注意力和流处理框架一致，其中说话人不连续性导致对新语音源的非自愿、刺激驱动的注意力重新定向，从而导致与说话人变化经典相关的处理干扰。
