Temporal integration of acoustic cues in fricative perception

Abstract

An important issue in speech perception is to determine how the components of a syllable interact to enhance perception of both consonant and vowel. To date the mechanism underlying that integration has not yet been discovered. Different approaches to the temporal integration between fricative and vowel in a set of natural syllables were explored. Two hypotheses were considered. (a) The two segments are evaluated separately and then combined into a single percept; (b) both cues are evaluated jointly. To test those hypotheses several computational models were considered. If the F and V segments are evaluated separately, two statistical functions are available: An ‘‘OR’’ function corresponding to the perceptual hypothesis predicting that only one of the segments determines the identity of the fricative; an ‘‘AND’’ function corresponding to the perceptual hypothesis predicting the use of both cues. The hypothesis of the joint evaluation of both cues was tested using the whole FV segment. Their performances were compared with the perceptual performance of a group of listeners in a fricative identification task. Although the joint evaluation model was superior to the other models, it was unable to extract the same benefits as listeners from the fricative–vowel interaction. [Work supported by Xunta de Galicia.]