The Role of Tempo and Primacy in Rhythm Similarity: A Multidimensional Scaling Evaluation

Abstract

Despite the long history of music psychology, rhythm similarity perception remains largely unexplored. Several existing studies suggest that the edit-distance model—which is based on the number of notational changes required to transform one rhythm into another—can predict rhythm similarity judgements. Nevertheless, edit-distance has not been evaluated in the presence of other musical factors such as rhythms that also differ in tempo. Here, eighteen participants rated the degree of similarity of a series of pair-wise rhythm phrases in which edit-distance was varied from 1 to 4, and tempo was set at either 90 or 150 beats per minute. Non-metric multidimensional scaling (nMDS) revealed that rhythm similarity ratings were clustered based upon either tempo or the identical onset pattern (i.e., primacy), but not based on edit-distance. Linear mixed effects modeling further confirmed the nMDS visualizations by yielding main effects of tempo and primacy. It also revealed interactions between edit-distance, tempo, and primacy, thus partially supporting edit-distance. That is, edit-distance predicted rhythm similarity only when tempo or primacy were controlled. Together, our findings suggest that the effects of tempo and primacy outweigh that of edit-distance, prompting a revision of theories regarding human percept of rhythm similarity.