An experimental comparison of formal measures of rhythmic syncopation

Rhythmic syncopation is one of the most fundamental features that can be used to characterize music. Therefore it can be applied in a variety of domains such as music information retrieval and style analysis. During the past twenty years a score of different formal measures of rhythmic syncopation have been proposed in the music literature. Here we compare eight of these measures with each other and with human judgements of rhythmic complexity. A data set of 35 rhythms ranked by human subjects was sorted using the eight syncopation measures. A Spearman rank correlation analysis of the rankings was carried out, and phylogenetic trees were calculated to visualize the resulting matrix of coefficients. The main finding is that the measures based on perception principles agree well with human judgements and very well with each other. The results also yield several surprises and open problems for further research.