Freyman Richard L, Morse-Fortier Charlotte, Griffin Amanda M
Department of Communication Disorders, University of Massachusetts, 358 North Pleasant Street, Amherst, Massachusetts 01003, USA.
J Acoust Soc Am. 2015 Sep;138(3):1418-27. doi: 10.1121/1.4927490.
When listeners know the content of the message they are about to hear, the clarity of distorted or partially masked speech increases dramatically. The current experiments investigated this priming phenomenon quantitatively using a same-different task where a typed caption and auditory message either matched exactly or differed by one key word. Four conditions were tested with groups of normal-hearing listeners: (a) natural speech presented in two-talker babble in a non-spatial configuration, (b) same as (a) but with the masker time reversed, (c) same as (a) but with target-masker spatial separation, and (d) vocoded sentences presented in speech-spectrum noise. The primary manipulation was the timing of the caption relative to the auditory message, which varied in 20 steps with a resolution of 200 ms. Across all four conditions, optimal performance was achieved when the initiation of the text preceded the acoustic speech signal by at least 400 ms, driven mostly by a low number of "different" responses to Same stimuli. Performance was slightly poorer with simultaneous delivery and much poorer when the auditory signal preceded the caption. Because priming may be used to facilitate perceptual learning, identifying optimal temporal conditions for priming could help determine the best conditions for auditory training.
当听众知晓即将听到的信息内容时，失真或部分被掩盖的言语清晰度会大幅提高。当前的实验使用了一个异同任务对这种启动现象进行了定量研究，在该任务中，一个打印的字幕与听觉信息要么完全匹配，要么相差一个关键词。对正常听力的听众群体测试了四种条件：(a) 在非空间配置的双说话者嘈杂环境中呈现的自然语音，(b) 与(a)相同，但掩蔽音时间反转，(c) 与(a)相同，但目标音与掩蔽音有空间分离，以及(d) 在语音频谱噪声中呈现的声码化句子。主要的操作是字幕相对于听觉信息的时间，以200毫秒的分辨率在20个步骤中变化。在所有四种条件下，当文本的起始时间比声学语音信号提前至少400毫秒时，可实现最佳性能，这主要是由对相同刺激的“不同”反应数量较少所驱动。同时呈现时性能略差，而当听觉信号先于字幕时性能则差得多。由于启动可用于促进感知学习，确定启动的最佳时间条件有助于确定听觉训练的最佳条件。
