Cognitive, neural, and social mechanisms of rhythmic interpersonal coordination

Humans possess the exceptional capacity to temporally coordinate their movements with one another with a high degree of accuracy, precision, and flexibility. Musical ensemble performance is a refined example of this, where a range of cognitive and sensory-motor processes work together to support rhythmic interpersonal coordination. However, the influence of social factors on the underlying cognitive-motor and neural mechanisms that facilitate rhythmic interpersonal coordination is yet to be established. This thesis draws on theoretical perspectives related to joint action, including co-representation, self-other integration and segregation, and theoretical models of sensorimotor synchronisation to consider this topic. Three experiments were conducted to investigate how social factors influence rhythmic interpersonal coordination. This broad empirical question was broken down by considering both extrinsic factors—such as the social context and perceived characteristics of an interaction partner (e.g. the degree of partner intentionality and responsiveness)—as well as intrinsic social factors, such as individual differences in attitudes and social preferences. This thesis concludes that extrinsic and intrinsic social factors affect rhythmic interpersonal coordination at multiple levels. A key aspect of this influence relates to how people regulate the integration and segregation of their representations of self and others. However, importantly, these effects are mediated by individual differences in intrinsic social factors such as personal preferences and biases. Top-down processes related to beliefs thus influence bottom-up sensorimotor processes during joint action, but the nature of this influence appears to be different for different people. This outcome highlights the necessity of taking individual differences into account, particularly when investigating the nuances of social processing during dynamic social interactions. Furthermore, the current findings suggest that beliefs about a partner during social interaction may be just as, or even more so, influential on performance than the actual characteristics of the partner. Recognising the potency of social beliefs has implications not only for research into basic psychological mechanisms underpinning rhythmic interpersonal coordination, but also for understanding the broader social dynamics of real-life situations involving cooperative joint action understanding the broader social dynamics of real-life situations involving cooperative joint action

The relationship between temporal anticipation and adaptation during sensorimotor synchronisation

Experienced music and dance ensembles can coordinate their movements with extreme temporal precision and accuracy, and yet remain flexible during constantly changing conditions. This sensorimotor synchronization requires individuals to continuously anticipate and adapt to each other’s action timing. Individuals differ in their ability to both anticipate and adapt, however little is understood about the relationship between these skills. The present study used paced finger tapping tasks to examine the relationship between anticipatory skill and adaptive (error correction) processes. In addition, the contribution of anticipatory and adaptive mechanisms, to individuals’ synchronization precision and accuracy was investigated. Adaptive ability was estimated by the degree of temporal error correction that participants (N=52) engaged in when synchronizing with a ‘virtual partner’, that is, an auditory pacing signal that modulated its timing based on the participant’s performance. Anticipation was measured by calculating a prediction index that reflected the degree to which participant’s inter-tap intervals led or lagged behind inter-onset intervals in tempo-changing sequences. A correlational analysis revealed a significant positive relationship between prediction/tracking indices and error correction estimates, suggesting that temporal anticipation and adaptation interact to facilitate synchronization performance. Hierarchical regression analyses revealed that adaptation was the best predictor of synchronization accuracy, whereas both adaptation and anticipation predicted synchronization precision. Together these results demonstrate a relationship between anticipatory and adaptive mechanisms and indicate that individual differences in these two abilities are predictive of synchronization performance

Individual differences in temporal anticipation and adaptation during sensorimotor synchronization

Interpersonal coordination during mnsical joint action (e.g., ensemble performance) requires individuals to anticipate and adapt to each other's action timing. Individuals differ in their ability to both anticipate and adapt, however, little is known about the relationship between these skills. The present study used paced finger tapping tasks to examine the relationship between anticipatory skill and adaptive (error correction) processes. Based on a computational model, it was hypothesized that temporal anticipation and adaptation will act together to facilitate synchronization accuracy and precision. Adaptive ability was measured as the degree of temporal error correction that participants (N = 52) engaged in when synchronizing with a 'virtual partner' that is, an auditory pacing signal that modulated its timing based on the participant's performance. Anticipation was measured through a prediction index that reflected the degree to which participants' inter-tap intervals led or lagged behind inter-onset intervals in tempo-changing sequences. A correlational analysis revealed a significant positive relationship between the prediction index and temporal error correction estimates, suggesting that anticipation and adaptation interact to facilitate synchronization performance. Hierarchical regression analyses revealed that adaptation was the best predictor of synchronization accuracy, whereas both adaptation and anticipation predicted synchronization precision. Together these results demonstrate a relationship between anticipatory and adaptive mechanisms, and indicate that individual differences in these two abilities are predictive of synchronization performance

Intentionality of a co-actor influences sensorimotor synchronisation with a virtual partner

Interpersonal sensorimotor synchronisation requires individuals to anticipate and adapt to their partner’s movement timing. Research has demonstrated that the intentionality of a co-actor affects joint action planning, however, less is known about whether co-actor intentionality affects sensorimotor synchronisation. Explicit and implicit knowledge of a synchronisation partner’s intentionality may influence coordination by modulating temporal anticipation and adaptation processes. We used a computer-controlled virtual partner (VP) consisting of tempo-changing auditory pacing sequences to simulate either an intentional or unintentional synchronisation partner. The VP was programmed to respond to the participant with low or moderate degrees of error correction, simulating a slightly or moderately adaptive human, respectively. In addition, task instructions were manipulated so that participants were told they were synchronising with either another person or a computer. Results indicated that synchronisation performance improved with the more adaptive VP. In addition, there was an influence of the explicit partner instruction, but this was dependent upon the degree of VP adaptivity and was modulated by subjective preferences for either the human or the computer partner. Beliefs about the intentionality of a synchronisation partner may thus influence interpersonal sensorimotor synchronisation in a manner that is modulated by preferences for interacting with intentional agents