Role Of Auditory Feedback Research Articles

Effects of experimental manipulations of auditory feedback upon vowels

The role of auditory feedback upon intermediate vowel production was explored by manipulating the amount and type of information provided by a Nucleus multichannel cochlear implant. Four experimental conditions ,were examined: (a) two types of control conditions, the implant turned on versus off, and (b) two experimental conditions that varied the channels being stimulated. Twenty repetitions of the vowels [ɪ], [ɛ], [i], [u] in an hVd context were acquired from four adventitiously deafened adults using multichannel implants. Two of the vowels, [ɪ] and [ɛ], were selected because of previous work indicating significant changes in formant frequencies when the implant was turned on versus off. The vowels [i] and [u] were included as controls since previous work indicated that their formant frequencies failed to change when the implant was turned off. Recordings were digitized at a 20‐kHz rate and analyzed using CSpeech. Fundamental frequency, formant frequencies, and duration measures were acquired for each token. Data were statistically treated using a repeated measures ANOVA. Preliminary data indicates that the intermediate vowels rely upon relevant auditory information more heavily for their production than the control, point vowels. [Work supported by NIDCD.]

Role of auditory feedback in canary song development.

As in other songbirds, early deafening had drastic effects on the song of the roller canary, a cardueline finch, resulting in a song that was much simpler and more variable than the normal. The repertoire of the syllable types, of which the song is made, was reduced from 30 to a mean of 5.0. Loud white noise was successfully used as a reversible method of cutting off auditory feedback from vocal behavior. Although suffering permanent elevation of hearing thresholds, birds reared in noise to 200 days, singing at first like deaf birds, subsequently increased their syllable repertoires significantly. Birds reared in noise to weaning at 40 days, again partly deaf, achieved a normal repertoire size when stimulated with a singing adult. Without such stimulation the repertoire was significantly reduced, showing that canary song is not fully innate, as had been thought. Although abnormal, the song of deaf canaries retained more species-specific features than did the song of emberizine sparrows when the songs developed without auditory feedback. The results are interpreted in terms of a sensory template theory.

The Role of Auditory Feedback in the Control of Vocalization in the White-Crowned Sparrow1

The Role of Auditory Feedback in the Control of Vocalization in the White-Crowned Sparrow¹