Attentional Demands Influence Vocal Compensations to Pitch Errors Heard in Auditory Feedback

Abstract

Auditory feedback is required to maintain fluent speech. At present, it is unclear how attention modulates auditory feedback processing during ongoing speech. In this event-related potential (ERP) study, participants vocalized/a/, while they heard their vocal pitch suddenly shifted downward a ½ semitone in both single and dual-task conditions. During the single-task condition participants passively viewed a visual stream for cues to start and stop vocalizing. In the dual-task condition, participants vocalized while they identified target stimuli in a visual stream of letters. The presentation rate of the visual stimuli was manipulated in the dual-task condition in order to produce a low, intermediate, and high attentional load. Visual target identification accuracy was lowest in the high attentional load condition, indicating that attentional load was successfully manipulated. Results further showed that participants who were exposed to the single-task condition, prior to the dual-task condition, produced larger vocal compensations during the single-task condition. Thus, when participants’ attention was divided, less attention was available for the monitoring of their auditory feedback, resulting in smaller compensatory vocal responses. However, P1-N1-P2 ERP responses were not affected by divided attention, suggesting that the effect of attentional load was not on the auditory processing of pitch altered feedback, but instead it interfered with the integration of auditory and motor information, or motor control itself.

Selective and divided attention modulates auditory–vocal integration in the processing of pitch feedback errors

“…However, our results revealed that cortical responses to pitch perturbations in the Visual Attention condition did not differ from those observed when participants passively observed the bimodal stimuli (i.e., Bimodal Passive condition). Similarly, Tumber et al (2014) reported that the P1-N1-P2 complex to pitch perturbations did not change when participants actively attended to the RSVP as compared to when they passively viewed the RSVP. In other words, increased attention to the visual stimuli, relative to the control condition, did not appear to suppress the cortical processing of auditory stimuli during the online control of vocal production.…”

“…Similarly, Tumber et al . () reported that actively attending to an RSVP elicited smaller vocal compensation for pitch perturbations than did passively viewing the RSVP. Note that only when participants were asked to passively view the RSVP before performing the vocal and RSVP task simultaneously did this modulation of vocal compensation occur, which was because the participants were unable to ignore the RSVP after previously performing a visual task (Scheerer & Jones, ).…”

“…Similarly, Tumber et al . () reported that the P1‐N1‐P2 complex to pitch perturbations did not change when participants actively attended to the RSVP as compared to when they passively viewed the RSVP. In other words, increased attention to the visual stimuli, relative to the control condition, did not appear to suppress the cortical processing of auditory stimuli during the online control of vocal production.…”

“…For example, Tumber et al . () investigated whether taxing central attentional processes affects auditory–motor integration by manipulating the visual attention load but did not manipulate the attention their participants paid to the pitch perturbations. Thus, the question of whether dividing attention between visual and auditory stimuli affects the auditory–motor processing of pitch perturbations remains unanswered.…”

“…Although the above-cited studies provide support for the hypothesis that there is a role for attention in auditory-motor integration during speech production, certain shortcomings in these two studies limit our understanding. For example, Tumber et al (2014) investigated whether taxing central attentional processes affects auditorymotor integration by manipulating the visual attention load but did not manipulate the attention their participants paid to the pitch perturbations. Thus, the question of whether dividing attention between visual and auditory stimuli affects the auditory-motor processing of pitch perturbations remains unanswered.…”