The developmental trajectory of rhythmic abilities in humans and singing primates

Rhythmicity is a composite competence that spans perceptual, motor, and socio-cognitive abilities. This is highly salient when adopting a developmental perspective, as we do in this chapter that reviews data from humans and other singing primate taxa with a close (gibbons) or remote (indri lemurs) phylogenetic relatedness to our species. The findings we review show that rhythmicity develops as an interplay between innate maturational processes and socio-ecological influences and that its underlying mechanisms have distinct developmental trajectories. Generally, however, the human data show that perceptual skills emerge earlier than motor ones. Moreover, both the human and nonhuman data show that rhythmic proficiency improves as (possibly innate) behavioural rhythms are brought under increased motor — and likely also cognitive — control. We surmise that developmental primate data are essential for understanding the underlying mechanisms and adaptive benefits of human rhythmic competence and the human-definitory forms of communication and cooperation that it enables. As this kind of data is exceedingly scarce, a substantial task of future research will be to reduce this gap. We also identify substantial gaps in current developmental research with human children, including the need to go beyond auditory rhythms and investigate rhythms broadcasted in other modalities as well, to increase the cross-cultural representativeness of the samples and to examine longitudinally the relationships between elements of the rhythmic composite.