Repetition without repetition: insights from rhythmic variability in music and dance
Music and dance seem to be very effective in making use of the channels available in human cognition to signalize cultural identities. Few seconds of exposition to an unknown musical excerpt or dance performance may be enough for an acculturated individual to grasp similarities among familiar styles, cultural and historical contexts, mood, or even to evaluate the musicians’ expertise. However, the ability to find these similarities is constructed from past repeated experiences, which are probably not identical and convey a variety of different patterns for the same perceived class. Literature on motor control has suggested that variability is intrinsic to all biological systems, which indicates that performance of a repetitive task at any level involves unique non-repetitive motor and neural patterns. In addition, the fine control of sound and movement variability seem to support expressive performances, which signalizes expertise and encodes personal signatures in music. The potential role of variability in music and dance cultures may imply that we should reconsider whether measuring repetition is an appropriate method to access the structure of rhythm in music and dance. In this study, we examine variability as a first order subject for modeling rhythm rather than treated it as a problem or deviation. More specifically, we analyze the patterns of variability encoded in the dispersion of rhythmic structures in music and dance performances, and how they provide a different viewpoint on the analysis of performances. The methods are inspired in studies on human motor variability combined with studies on musical gesture and expressive timing. The datasets are composed of motion capture recordings and commercial audio samples of Afro-Brazilian samba music and dance. As a final point, we discuss the variability in the theories of motor behavior, reexamining the modeling approaches that substantiate theories of meter and rhythm in music.
presentation slides available here