Attention and Vigilance in Speech Perception

摘要

This report describes research carried out in three related projects investigating the function and limitations of attention in speech perception. The projects were directed at investigating the distribution of attention in time during phoneme recognition, perceptual normalization of talker differences, and perceptual learning of synthetic speech. The first project demonstrates that in recognizing phonemes listeners attend to earlier and later phonetic context, even when that context is in another syllable. The second project demonstrated that there are two mechanisms underlying the ability of listeners to recognize speech across talkers. The first, structural estimation, is based on computing a talker-independent representation of each utterance on its own; the second, contextual tuning, is based on learning the vocal characteristics of the talker. Structural estimation requires more attention and effort than contextual tuning. The final project examined the attentional demands of synthetic speech and how they change with perceptual learning. The results demonstrated that the locus of attentional demands in perception of synthetic speech is in recognition rather than storage or recall of synthetic speech. Moreover, perceptual learning increases the efficiency with which listeners can use spare capacity in recognizing synthetic speech and this effect is not just due to increased intelligibility. Our results suggest that perceptual learning allows listeners to focus on the relevant acoustic-phonetic properties of a particular, synthetic talker. (sdw)