Expressing melodic grouping discontinuities: Evidence from violinists’ rubato and motion

Abstract

Within phrases, melodies can be perceived as continuous or discontinuous. Large pitch intervals tend to promote the perception of melodic discontinuity, though surrounding pitch contexts can promote or diminish this percept. The present study investigated if performers express discontinuities in rubato and motion. In Experiment 1, audio and motion capture recordings were made of six violinists performing a piece with pairs of segments containing strong and weak discontinuities. Violinists’ rubato computed from audio onsets differentiated between discontinuity types. A principal component analysis of the motion data revealed that nontechnical whole-body motions explained a significant amount of variance corresponding to the discontinuity types, although the strength of the effect varied across analyzed segments. In Experiment 2, the motion and audio data were used to create audiovisual stimuli to examine whether these components influenced judgments of discontinuity in third-party audiences. Participants saw, heard, or both saw and heard the performed segments with either natural motion or altered motion after nontechnical principal components were removed, then judged whether violinists expressed either one or two groups of notes. Similar to Experiment 1, variation between segments in differentiation between discontinuity types was observed only when participants saw the violinists’ natural motion. Together, these data suggest that violinists can express melodic continuity through timing and motion, though expression through motion is relatively subtle and variable across individuals. Our results extend previous findings of the relationship between performer interpretation and motion to local musical structures, demonstrating observations across multiple performers with a previously less-studied instrument, namely, the violin.