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.

与一个一致的说话者相比，不连续的、混合的说话者的语音处理效率较低，但人们对处理说话者变异性的神经机制知之甚少。在这里，我们使用脑电图 (EEG) 和瞳孔测量法测量了说话者变异性的心理生理反应，同时听众执行了数字跨度任务的延迟回忆。听众听到并回忆起七位数序列，其中说话者（单一与混合说话者数字）和时间（0 与 500 毫秒数字间间隔）不连续。谈话者的不连续性降低了连续回忆的准确性。说话者和时间的不连续性都会引发 P3a 样神经诱发反应，而混合说话者语音的快速处理会导致阶段性瞳孔扩张增加。此外，混合说话者的语音在工作记忆维护期间产生的 alpha 振荡功率较小，但在语音编码期间则不然。总的来说，这些结果与听觉注意和流式框架一致，在该框架中说话者的不连续性导致非自愿的、刺激驱动的注意力重新定向到新的语音源，从而导致处理干扰通常与说话者的可变性相关。