Date Published: July 5, 2017
Publisher: Public Library of Science
Author(s): Pamela Trudeau-Fisette, Mark Tiede, Lucie Ménard, Hanjun Liu.
This study investigated the effects of visual deprivation on the relationship between speech perception and production by examining compensatory responses to real-time perturbations in auditory feedback. Specifically, acoustic and articulatory data were recorded while sighted and congenitally blind French speakers produced several repetitions of the vowel /ø/. At the acoustic level, blind speakers produced larger compensatory responses to altered vowels than their sighted peers. At the articulatory level, blind speakers also produced larger displacements of the upper lip, the tongue tip, and the tongue dorsum in compensatory responses. These findings suggest that blind speakers tolerate less discrepancy between actual and expected auditory feedback than sighted speakers. The study also suggests that sighted speakers have acquired more constrained somatosensory goals through the influence of visual cues perceived in face-to-face conversation, leading them to tolerate less discrepancy between expected and altered articulatory positions compared to blind speakers and thus resulting in smaller observed compensatory responses.
The study consisted of two experiments, a speech perception task and a speech production task, which were conducted in a single session. This research was approved by the Université du Québec à Montréal’s Institutional Review Board (no 2012-05-4.3), and all participants gave written, informed consent.
The goal of this study was to examine the acoustic and articulatory compensatory behaviors in response to real-time manipulations of acoustic feedback among sighted and blind adult speakers. By analyzing the impact of blindness on the acoustic and articulatory behaviors in response to acoustic manipulations, this research assesses the contribution of vision to the speech perception and production mechanisms. To our knowledge, this was the first study to investigate this, and the results supported the first two of our three hypotheses.
This study showed that blind and sighted speakers responded differently to a real-time manipulation of their auditory feedback. An observation of the weight given to auditory feedback in an acoustic manipulation task showed that blind participants granted more importance to the auditory information than their sighted peers.