The concept of agency refers to the sense of control of one’s actions. From the viewpoint of dynamic cognition, this is conceived in terms of anticipatory models that predict sensory outcomes of actions. A match between the predicted outcome and the sensory inflow is seen as a marker for agency. Fritz et al. (2013) show that musical agency, in a context of strenuous activities, can dramatically reduce the perception of exertion. This suggests that agency draws attention to musical states rather than body states. To explain this, we argue that musical expression requires a degree of spontaneity which can only be achieved by monitoring sensory inflow in real time.
Our assumption is that musical expression relies on low-level automatic motor control adequate to the real-time matching of audio effect to intended musical action. Note that even small variations in the realization of these intentions would have a great impact on expressive phrasing. This is comparable to speech prosody where emphasis on a singular phoneme can change the meaning of a whole sentence. We assume that the perceived reduction in physical exertion during this type of spontaneous motor control is due to the process of combining low-level gestural patterns, motorically already well established, into larger expressive gestures. The modulating influence of this process of constant monitoring on perceived exertion may be two-fold: 1. The task of combining the gestural building block in real-time may demand so many attentional resources that fewer are devoted to bodily exertion, 2. The use of automated gestural building blocks is achieved by a non-deliberate (possibly emotional) system of motor control. This might entail a survival related optimization of control that is perceived as less taxing. The process of expressive gestural control may have its basis in social communication and thus be most prominent during musical interactions.