Peter Keller

The ability to distinguish between an individual's own actions and those of another person is a requirement for successful joint action, particularly in domains such as group music making where precise interpersonal coordination ensures perceptual overlap in the effects of co-performers' actions. We tested the hypothesis that such coordination benefits from simultaneous integration and segregation of information about ‘self’ and ‘other’ in an experiment using a musical joint action paradigm. Sixteen pairs of individuals with little or no musical training performed a dyadic synchronization task on a pair of electronic music boxes. The relationship between pitches produced by paired participants (same vs. different) and the relationship between movement frequencies required to trigger synchronous tones (congruent vs. incongruent) were varied in a repeated measures design. The results indicate that interpersonal coordination was most accurate when sounds were different in pitch but movement frequency was congruent. Under other conditions, participants often drifted apart, resulting in poor coordination, especially with same sounds and incongruent movements across co-performers. These findings suggest that interpersonal coordination was facilitated when simultaneous self-other integration and segregation occurred across sensory modalities in an asymmetrical manner where pitch relations favoured segregation via auditory streaming while movement congruence favoured integration via visuo-motor coupling. Such self-other representational balance may enable co-performers to maintain autonomous control while attending, anticipating, and adapting to each other's timing when joint action requires precise temporal coordination.

Ensemble musicians play in synchrony despite expressively motivated irregularities in timing. We hypothesized that synchrony is achieved by each performer internally simulating the concurrent actions of other ensemble members, relying initially on how they would perform in their stead. Hence, musicians should be better at synchronizing with recordings of their own earlier performances than with others’ recordings. We required pianists to record one part from each of several piano duets, and later to play the complementary part in synchrony with their own or others’ recordings. The pianists were also asked to identify their own recordings. The pianists were better at synchronizing with their own than with others’ performances, and they were able to recognize their own recordings. Furthermore, synchronization accuracy and recognition were correlated: Pianists who were relatively accurate at synchronizing with their own performances were also good at recognizing them. Thus, action simulation may underlie both synchronization and self-recognition

The present study investigates shared representations of syntactic knowledge in music and action. We examined whether expectancy violations in musical harmonic sequences are also perceived as violations of the movement sequences necessary to produce them. Pianists imitated silent videos showing one hand playing chord sequences on a muted keyboard. Results indicate that, despite the absence of auditory feedback, imitation of a chord is fastest when it is congruent with the preceding harmonic context. This suggests that the harmonic rules implied by observed actions induce expectations that influence action execution. As evidence that these predictions are derived at a high representational level, imitation was more accurate for harmonically incongruent chords than for congruent chords executed with unconventional fingering. The magnitude of the effects of context and goal prioritization increased with musical training. Thus, musical training may lead to a domain-general representation of musical grammar, i.e., to a grammar of action

Self–other discrimination was investigated with point-light displays in which actions were presented with or without additional auditory information. Participants first executed different actions in time with music. In two subsequent experiments, they watched point-light displays of their own or another participant’s recorded actions, and were asked to identify the agent . Manipulations were applied to the visual information and to the auditory information . Results indicate that self-recognition was better than chance in all conditions and was highest when observing relatively unconstrained patterns of movement. Auditory information did not increase accuracy even with the most ambiguous visual displays, suggesting that judgments of agent identity depend much more on motor cues than on auditory or audiovisual information