The dynamics of disruption from altered auditory feedback: Further evidence for a dissociation of sequencing and timing

Three experiments were designed to test whether perception and action are coordinated in a way that distinguishes sequencing from timing (Pfordresher, 2003). Each experiment incorporated a trial design in which altered auditory feedback (AAF) was presented for varying lengths of time and then withdrawn. Experiments 1 and 2 included AAF that resulted in action-effect asynchronies (delayed auditory feedback) during simple tapping (Experiment 1) and melody production (Experiment 2). Asynchronous AAF immediately slowed production; this effect then diminished rapidly after removal of AAF. By contrast, sequential alterations of feedback pitch during melody production (Experiment 3) had an effect that varied over successive presentations of AAF (by increasing error rates) that lasted after its withdrawal. The presence of auditory feedback after withdrawal of asynchronous AAF (Experiments 1 and 2) led to overcompensation of timing, whereas the presence of auditory feedback did not influence performance after withdrawal of AAF in Experiment 3. Based on these results, we suggest that asynchronous AAF perturbs the phase of an internal timekeeper, whereas alterations to feedback pitch over time degrade the internal representation of sequence structure.     

“Deafness” effects in detecting alterations to auditory feedback during sequence production

Past research has shown that when discrete responses are associated with a perceptual goal, performers may have difficulty detecting stimuli that are commensurate with that goal. Three experiments are reported here that test whether such effects extend to sequence production. In Experiment 1, participants performed 8-note melodies repeatedly, and on each trial a single tone could be altered with respect to its pitch and/or synchrony with actions. Results suggested a selective deficit of detection when feedback pitch was unchanged and the event was slightly delayed. Experiment 2 showed that this “deafness” to feedback is limited to rhythmic motor tasks that require sequencing, in that similar effects did not emerge when participants produced pitch sequences by tapping a single key repeatedly. A third experiment demonstrated similar results to Experiment 1 when the mapping of keys to pitches on the keyboard was reversed. Taken together, results suggest a selective deafness to response-congruent delayed feedback, consistent with the idea that performers suppress previously planned events during production.     

Effects of altered auditory feedback across effector systems: production of melodies by keyboard and singing

We report an experiment that tested whether effects of altered auditory feedback (AAF) during piano performance differ from its effects during singing. These effector systems differ with respect to the mapping between motor gestures and pitch content of auditory feedback. Whereas this action-effect mapping is highly reliable during phonation in any vocal motor task (singing or speaking), mapping between finger movements and pitch occurs only in limited situations, such as piano playing. Effects of AAF in both tasks replicated results previously found for keyboard performance (Pfordresher, 2003), in that asynchronous (delayed) feedback slowed timing whereas alterations to feedback pitch increased error rates, and the effect of asynchronous feedback was similar in magnitude across tasks. However, manipulations of feedback pitch had larger effects on singing than on keyboard production, suggesting effector-specific differences in sensitivity to action-effect mapping with respect to feedback content. These results support the view that disruption from AAF is based on abstract, effector independent, response-effect associations but that the strength of associations differs across effector systems.     

Auditory imagery and the poor-pitch singer

The vocal imitation of pitch by singing requires one to plan laryngeal movements on the basis of anticipated target pitch events. This process may rely on auditory imagery, which has been shown to activate motor planning areas. As such, we hypothesized that poor-pitch singing, although not typically associated with deficient pitch perception, may be associated with deficient auditory imagery. Participants vocally imitated simple pitch sequences by singing, discriminated pitch pairs on the basis of pitch height, and completed an auditory imagery self-report questionnaire (the Bucknell Auditory Imagery Scale). The percentage of trials participants sung in tune correlated significantly with self-reports of vividness for auditory imagery, although not with the ability to control auditory imagery. Pitch discrimination was not predicted by auditory imagery scores. The results thus support a link between auditory imagery and vocal imitation.     

Enhanced production and perception of musical pitch in tone language speakers

Individuals differ markedly with respect to how well they can imitate pitch through singing and in their ability to perceive pitch differences. We explored whether the use of pitch in one’s native language can account for some of the differences in these abilities. Results from two studies suggest that individuals whose native language is a tone language, in which pitch contributes to word meaning, are better able to imitate (through singing) and perceptually discriminate musical pitch. These findings support the view that language acquisition fine-tunes the processing of critical auditory dimensions in the speech signal and that this fine-tuning can be carried over into nonlinguistic domains.     

Effects of hearing the past, present, or future during music performance

Three experiments were performed to explore the effects of mismatches between actions (key-presses) and the contents of auditory feedback (pitch events) during music performance. Pianists performed melodies from memory during altered auditory feedback that was synchronized with key-presses but matched the pitch of other sequence events. Feedback direction was manipulated by presenting pitches that matched events intended for the past (delays; Experiments 1 and 3) or the future (prelays; Experiments 2 and 3). Feedback distance was manipulated by varying the absolute separation between the current event and the location of the feedback pitch. All alterations disrupted the accuracy of performance (pitch errors) more so than timing. Serial-ordering errors indicated confusions among proximal and metrically similar events, consistent with the predictions of an incremental planning model (Palmer & Pfordresher, 2003). Patterns of serial-ordering errors suggested that performers compensate for the disruptive effects of altered feedback by changing event activations during planning.     

Auditory feedback in music performance: the role of melodic structure and musical skill

Five experiments explored whether fluency in musical sequence production relies on matches between the contents of auditory feedback and the planned outcomes of actions. Participants performed short melodies from memory on a keyboard while musical pitches that sounded in synchrony with each keypress (feedback contents) were altered. Results indicated that altering pitch contents can disrupt production, but only when altered pitches form a sequence that is structurally similar to the planned sequence. These experiments also addressed the role of musical skill: Experiments 1 and 3 included trained pianists; other experiments included participants with little or no musical training. Results were similar across both groups with respect to the disruptive effects of auditory feedback manipulations. These results support the idea that a common hierarchical representation guides sequences of actions and the perception of event sequences and that this coordination is not acquired from learned associations formed by musical skill acquisition.     

The experience of agency in sequence production with altered auditory feedback

When speaking or producing music, people rely in part on auditory feedback - the sounds associated with the performed action. Three experiments investigated the degree to which alterations of auditory feedback (AAF) during music performances influence the experience of agency (i.e., the sense that your actions led to auditory events) and the possible link between agency and the disruptive effect of AAF on production. Participants performed short novel melodies from memory on a keyboard. Auditory feedback during performances was manipulated with respect to its pitch contents and/or its synchrony with actions. Participants rated their experience of agency after each trial. In all experiments, AAF reduced judgments of agency across conditions. Performance was most disrupted (measured by error rates and slowing) when AAF led to an ambiguous experience of agency, suggesting that there may be some causal relationship between agency and disruption. However, analyses revealed that these two effects were probably independent. A control experiment verified that performers can make veridical judgments of agency.     

Individuals with congenital amusia imitate pitches more accurately in singing than in speaking: Implications for music and language processing

In this study, we investigated the impact of congenital amusia, a disorder of musical processing, on speech and song imitation in speakers of a tone language, Mandarin. A group of 13 Mandarin-speaking individuals with congenital amusia and 13 matched controls were recorded while imitating a set of speech and two sets of song stimuli with varying pitch and rhythm patterns. The results indicated that individuals with congenital amusia were worse than controls in both speech and song imitation, in terms of both pitch matching (absolute and relative) and rhythm matching (relative time and number of time errors). Like the controls, individuals with congenital amusia achieved better absolute and relative pitch matching and made fewer pitch interval and contour errors in song than in speech imitation. These findings point toward domain-general pitch (and time) production deficits in congenital amusia, suggesting the presence of shared pitch production mechanisms but distinct requirements for pitch-matching accuracy in language and music processing.     

Effects of delayed auditory feedback on timing of music performance

Three experiments examined effects of delayed auditory feedback (DAF) on music performance as a function of the temporal location of feedback onsets within produced inter-onset intervals (IOIs). In Experiment 1, pianists performed isochronous melodies at two production rates with different amounts of DAF. Timing variability decreased for DAF amounts that caused feedback onsets to occur halfway through IOIs (binary subdivisions) in a 500-ms, but not 600-ms, IOI rate condition. In Experiment 2, pianists performed melodies with DAF delays and chose a preferred rate. Performers chose slower rates for larger delays; preferred rates approximated twice the amount of DAF. Experiment 3 tested the possibility that subjects deliberately conceptualized subdivisions in Experiments 1 and 2. Performers were given (1) no instructions, (2) instructions to mentally subdivide produced events in two, or (3) instructions to mentally subdivide produced events in three, in different blocks. Instructions to subdivide reduced timing variability for larger feedback delays. These experiments indicate that DAF disruption is reduced by subdividing instructions and sometimes by coincidences of feedback onsets with subdivisions of produced intervals. Such facilitation may reflect the use of hierarchical cognitive plans in production.