A temporally dynamic context effect that disrupts voice onset time discrimination of rapidly successive stimuli

Abstract

Across three experiments, voice onset time discrimination along a/ba/-/pa/ continuum was found to be influenced by the order of presentation of rapidly successive stimuli. Specifically, discrimination was disrupted when a relatively unambiguous /pa/ syllable was presented before, rather than after, a more ambiguous /pa/ or /ba/ syllable. In Experiments 1 and 2, for between-category discrimination, this order effect was significant at interstimulus intervals (ISIs) below 250 msec, but not at 250 or 1,000 msec. In Experiments 2 and 3, the order effect was also significant for within-category discrimination at ISIs below 250 msec. In addition, in Experiment 3 this order effect was not diminished by provision of performance feedback across eight testing sessions. These findings reveal a particular vulnerability of phonological processing in response to rapidly successive stimuli and may have implications for mathematical and neural models of speech processing of normal and impaired populations. Copyright 2005 Psychonomic Society, Inc.