Some movements that musicians make are non-essential to their instrumental playing, yet express their intentions and interpretations of music’s structures. One such potential interpretation is the choice to emphasize short melodic groupings or to integrate these groupings into a phrase. This study aimed to characterize the nature of head motions associated with either interpretation by having cellists play two versions of a musical excerpt: 1) with short groupings specified, and 2) with long groupings specified. Cellists were filmed by two video cameras (front and right-side perspective) and the positions of their forehead and cheek were analyzed in their respective two-dimensional spaces. We hypothesized that the amount and frequency of movements would change according to the intended grouping. The results show that, overall, participants’ heads move more frequently when intending short groupings compared to long groupings. However, the extent of the change in motion varied across different sections of the excerpt. It appears that performers may invest more effort to emphasize the intended interpretation when a given local pitch structure more easily affords alternative interpretations. Our results illustrate that performers can embody melodic groupings based on intended interpretation.
