ABSTRACT
The capacity for auditory–motor coordination (AMC) is shared by several species, among which humans are most flexible in coordinating with tempo changes. We investigated how humans lose this tempo flexibility at their upper rate limit, and the effect of skill level on this phenomenon. Seven skilled street dancers, including a world champion, and 10 non-dancers were instructed to bend their knees according to a metronome beat in a standing position at eight constant beat frequencies (3.8–5 Hz). Although maximum frequency of movement during the task was 4.8 Hz in the non-dancers and 5.0 Hz in the dancers, the rate limit for AMC was 4.1 Hz in the non-dancers and 4.9 Hz in the dancers. These results suggest that the loss of AMC was not due to rate limit of movement execution but rather to a constraint on the AMC process. In addition, mediation analysis revealed that a kinematic bias (i.e. the extent of knee flexion during the task) causally affected the extent of phase wandering via mediating factors (e.g. the extent to which movement frequency was reduced relative to the beat frequency). These results add evidence that gravity acts as constraint on AMC involving vertical rhythmic movement.
Footnotes
Author contributions
Conceptualization: A.M., K.K., K.N.; Methodology: A.M., S.F., M.O., K.K., K.N.; Software: A.M., S.F., M.O.; Validation: A.M., M.O.; Formal analysis: A.M., S.F., M.O.; Writing - original draft: A.M., S.F.; Writing - review & editing: A.M., S.F., M.O., K.K., K.N.; Supervision: K.K., K.N.; Project administration: A.M., K.K., K.N.; Funding acquisition: A.M.
Funding
This research was partly supported by Grants-in-Aid from the Japan Society for the Promotion of Science (JSPS) for JSPS Fellows awarded to A.M. (no. 23-9480 and no. 25-6687), and by financial aid from Advanced Research Center for Human Sciences, Waseda University to A.M. as a member of the Research Project C, ‘A basic and applied study of movements based on Bernstein's idea of coordination’ (PI: Nobuhiro Furuyama).
Data availability
Data are available from the Dryad Digital Repository (Miura et al., 2018): https://doi.org/10.5061/dryad.4dh955q