Making and monitoring errors based on altered auditory feedback.

Previous research has demonstrated that altered auditory feedback (AAF) disrupts music performance and causes disruptions in both action planning and the perception of feedback events. It has been proposed that this disruption occurs because of interference within a shared representation for perception and action (Pfordresher, 2006). Studies reported here address this claim from the standpoint of error monitoring. In Experiment 1 participants performed short melodies on a keyboard while hearing no auditory feedback, normal auditory feedback, or alterations to feedback pitch on some subset of events. Participants overestimated error frequency when AAF was present but not for normal feedback. Experiment 2 introduced a concurrent load task to determine whether error monitoring requires executive resources. Although the concurrent task enhanced the effect of AAF, it did not alter participants' tendency to overestimate errors when AAF was present. A third correlational study addressed whether effects of AAF are reduced for a subset of the population who may lack the kind of perception/action associations that lead to AAF disruption: poor-pitch singers. Effects of manipulations similar to those presented in Experiments 1 and 2 were reduced for these individuals. We propose that these results are consistent with the notion that AAF interference is based on associations between perception and action within a forward internal model of auditory-motor relationships.

Impacts of age on memory for auditory intensity.

It is hypothesized that older listeners are more likely than younger listeners to be impaired when asked to make intensity judgments about target tones embedded in rapidly presented auditory sequences. This study examined this hypothesis by asking listeners ranging in age from 19 to 74 yr to make judgments of intensity based on narrowband noise bursts varying in frequency and intensity. In two experiments, listeners made intensity judgments of target bursts alone or embedded in sequences of bursts. In the first experiment, one of four fixed sequences was presented and had to be identified. In the second experiment, pre- or post-trial bursts acted as cues that identified the frequency of the target burst in the sequence. In both experiments, intensity discrimination thresholds for single bursts were good predictors of performance with sequences and were little affected by age. Significant negative relationships between age and accuracy were observed when single sequences had to be identified or a post-trial cue was used, but no age effects were apparent when a pre-trial cue was used. These data are interpreted as being consistent with previous suggestions that the aging process results in a decline in auditory memory capacity and/or internally generated selective attention.

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.