Do listeners to speech perceive gestures? Evidence from choice and simple response time tasks

Abstract

According to the motor and direct realist theories, listeners perceive speech gestures. The following experiments test this claim. Experiments 1 and 2 replicate the findings of Porter and Castellanos [J. Acoust. Soc. Am. 67, 1349–1356 (1980)]. Participants shadowed vowel-consonant-vowels (VCVs) produced by a model. Responses were timed. The difference between response times (RT) in simple and choice speech shadowing tasks (26 ms) is shorter than the canonical choice/simple RT difference [100–150 ms, Luce (Oxford, New York, 1986)]. This is interpreted as supporting Porter and Castellanos, in that when the task is to shadow speech, the element of choice is considerably reduced as the listener receives instructions for her response from the speech sounds she perceives. In experiment 3, the timing of gestures of the models’ speech was manipulated by extending the voice onset time (VOT) of the models’ production of voiceless stops in half of the speakers VCVs. VOTs of participants shadowed responses were measured. Our findings suggest that listeners’ productions of phonemes can be influenced by their perception of the timing of the models’ gestures in speech shadowing tasks. This provides additional support for the interpretation that participants’ shadowing responses are guided by their preception of the models’ gestures.