Holmes Emma, Kitterick Padraig T, Summerfield A Quentin
Department of Psychology, University of York, UK.
NIHR Nottingham Hearing Biomedical Research Unit, UK; Division of Clinical Neuroscience, School of Medicine, University of Nottingham, UK.
Hear Res. 2016 Jun;336:83-100. doi: 10.1016/j.heares.2016.04.007. Epub 2016 May 10.
Selective attention is critical for successful speech perception because speech is often encountered in the presence of other sounds, including the voices of competing talkers. Faced with the need to attend selectively, listeners perceive speech more accurately when they know characteristics of upcoming talkers before they begin to speak. However, the neural processes that underlie the preparation of selective attention for voices are not fully understood. The current experiments used electroencephalography (EEG) to investigate the time course of brain activity during preparation for an upcoming talker in young adults aged 18-27 years with normal hearing (Experiments 1 and 2) and in typically-developing children aged 7-13 years (Experiment 3). Participants reported key words spoken by a target talker when an opposite-gender distractor talker spoke simultaneously. The two talkers were presented from different spatial locations (±30° azimuth). Before the talkers began to speak, a visual cue indicated either the location (left/right) or the gender (male/female) of the target talker. Adults evoked preparatory EEG activity that started shortly after (<50 ms) the visual cue was presented and was sustained until the talkers began to speak. The location cue evoked similar preparatory activity in Experiments 1 and 2 with different samples of participants. The gender cue did not evoke preparatory activity when it predicted gender only (Experiment 1) but did evoke preparatory activity when it predicted the identity of a specific talker with greater certainty (Experiment 2). Location cues evoked significant preparatory EEG activity in children but gender cues did not. The results provide converging evidence that listeners evoke consistent preparatory brain activity for selecting a talker by their location (regardless of their gender or identity), but not by their gender alone.
选择性注意对于成功的言语感知至关重要，因为言语常常是在存在其他声音的情况下出现的，包括竞争说话者的声音。面对选择性注意的需求，当听众在即将说话的人开始说话之前了解其特征时，他们能更准确地感知言语。然而，为声音准备选择性注意的神经过程尚未完全明了。当前的实验使用脑电图（EEG）来研究18 - 27岁听力正常的年轻人（实验1和2）以及7 - 13岁发育正常的儿童（实验3）在为即将到来的说话者做准备时大脑活动的时间进程。当异性干扰说话者同时说话时，参与者报告目标说话者说出的关键词。两个说话者从不同空间位置呈现（±30°方位角）。在说话者开始说话之前，一个视觉提示表明目标说话者的位置（左/右）或性别（男/女）。成年人在视觉提示出现后不久（<50毫秒）就诱发了准备性EEG活动，并持续到说话者开始说话。在实验1和2中，不同参与者样本的位置提示诱发了类似的准备性活动。当性别提示仅预测性别时（实验1），没有诱发准备性活动，但当它更确定地预测特定说话者的身份时（实验2），确实诱发了准备性活动。位置提示在儿童中诱发了显著的准备性EEG活动，但性别提示没有。结果提供了一致的证据，即听众通过说话者的位置（无论其性别或身份）而非仅通过其性别来诱发一致的准备性大脑活动以选择说话者。
