Categorical Perception of Consonants and Vowels: Evidence from a Neurophonetic Model of Speech Production and Perception

Abstract

While the behavioral side of categorical perception in speech is already well investigated, little is known concerning its underlying neural mechanisms. In this study, a computer-implemented neurophonetic model of speech production and perception is used in order to elucidate the functional neural mechanisms responsible for categorical perception. 20 instances of the model (virtual listeners/speakers) underwent a speech acquisition training procedure and then performed behavioral tests, i.e. identification and discrimination experiments based on vocalic and CV-syllabic speech stimuli. These virtual listeners showed the expected behavioral results. The inspection of the neural organization of virtual listeners indicated clustering in the case of categorical perception and no clustering in the case of non-categorical (continuous) perception for neurons representing the stimuli. These results highlight a possible neural organization underlying categorical and continuous perception.