Measuring Similarity between Flamenco Rhythmic Patterns

Music similarity underlies a large part of a listener’s experience, as it relates to familiarity and associations between different pieces or parts. Rhythmic similarity has received scant research attention in comparison with other aspects of music similarity such as melody or harmony.

Mathematical measures of rhythmic similarity have been proposed, but none of them has been compared to humanjudgments. We present a first study consisting of two listening tests conducted to compare two mathematical similarity measures, the chronotonic distance and the directed swap distance, to perceptual measures of similarity.

In order to investigate the effect of expertise on the perception of rhythmic similarity, we contrasted three groups of participants, namely non-musicians, classically trained percussionists and flamenco musicians. Results are presented in terms of statistical analysis of the raw ratings, phylogenetic analysis of the dissimilarity matrices, correlation with mathematical measures and qualitative analysis of spontaneous verbal descriptions reported by participants. A main effect of expertise was observed on the raw ratings, but not on the dissimilarity matrices. No effect of tempo was observed.

Results of both listening tests converge to show that the directed-swap distance best matches human judgments of similarity regardless of expertise. The analysis of verbal descriptions indicates that novice listeners focused on ‘surface’ features, while musicians focused on the underlying rhythmic structure and used more specialized vocabulary.