Perception of speech reflects optimal use of probabilistic speech cues.
Listeners are exquisitely sensitive to fine-grained acoustic detail within phonetic categories for sounds and words. Here we show that this sensitivity is optimal given the probabilistic nature of speech cues. We manipulated the probability distribution of one probabilistic cue, voice onset time (VOT), which differentiates word initial labial stops in English (e.g., "beach" and "peach"). Participants categorized words from distributions of VOT with wide or narrow variances. Uncertainty about word identity was measured by four-alternative forced-choice judgments and by the probability of looks to pictures. Both measures closely reflected the posterior probability of the word given the likelihood distributions of VOT, suggesting that listeners are sensitive to these distributions.
Clayards
Meghan
M
Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA. mclayards@bcs.rochester.edu
Tanenhaus
Michael K
MK
Aslin
Richard N
RN
Jacobs
Robert A
RA
D032882:Comprehension; D003463:Cues; D006801:Humans; D007600:Judgment; D015233:Models, Statistical; D010364:Pattern Recognition, Visual; D010700:Phonetics; D013061:Speech Acoustics; D013067:Speech Perception