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The nonlinear dynamics of speech categorization.

B Tuller·P Case·M Ding·J A Kelso
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Abstract

Little is known about the processes underlying the nonlinear relationship between acoustics and speech perception. In Experiment 1, we explored the effects of systematic variation of a single acoustic parameter (silent gap duration between a natural utterance of s and a synthetic vowel ay) on judgements of speech category. The resulting shifts in category boundary between say and stay showed rich dynamics, including hysteresis, contrast, and critical boundary effects. We propose a dynamical model to account for the observed patterns. Experiment 2 evaluated one prediction of the model, that changing the relative stability of the two percepts allows categorical switching. In agreement with the model; an increase in the number of stimulus repetitions maximized the frequency of judgments of category change near the boundary. Thus, a dynamical approach affords the rudiments for a theory of the effects of temporal context on speech categorization.

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Acoustic StimulationAdolescentAdultFemaleHumansMaleSpeech AcousticsSpeech PerceptionJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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B Tuller, P Case, M Ding, J A Kelso. 1994. The nonlinear dynamics of speech categorization.. https://doi.org/10.1037/%2F0096-1523.20.1.3

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