Continuous perception and graded categorization: electrophysiological evidence for a linear relationship between the acoustic signal and perceptual encoding of speech.

ABSTRACT: Speech sounds are highly variable, yet listeners readily extract information from them and transform continuous acoustic signals into meaningful categories during language comprehension. A central question is whether perceptual encoding captures acoustic detail in a one-to-one fashion or whether it is affected by phonological categories. We addressed this question in an event-related potential (ERP) experiment in which listeners categorized spoken words that varied along a continuous acoustic dimension (voice-onset time, or VOT) in an auditory oddball task. We found that VOT effects were present through a late stage of perceptual processing (N1 component, ~100 ms poststimulus) and were independent of categorization. In addition, effects of within-category differences in VOT were present at a postperceptual categorization stage (P3 component, ~450 ms poststimulus). Thus, at perceptual levels, acoustic information is encoded continuously, independently of phonological information. Further, at phonological levels, fine-grained acoustic differences are preserved along with category information.

SUBMITTER: Toscano JC 

PROVIDER: S-EPMC3523688 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature