P W Fink, J A Kelso, V K Jirsa, and G de Guzman (2000)
Recruitment of degrees of freedom stabilizes coordination
JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE 26(2):671–692.
By showing that transitions may be obviated by recruiting degrees
of freedom in the coupled pendulum paradigm, the authors reveal
a novel mechanism for coordinative flexibility. In Experiment 1,
participants swung pairs of unconstrained pendulums in 2 planes
of motion (sagittal and frontal) at 8 movement frequencies starting
from either an in-phase or antiphase mode. Few transitions were
observed. Measures of spatial trajectory showed recruitment effects
tied to the stability of the initial coordinative pattern. When
the motion of the pendulums was physically restricted to a single
plane in Experiment 2, transitions were more common, indicating
that recruitment delays-or even eliminates-transitions. Such recruitment
complements transitions as a source of coordinative flexibility
and is incorporated in a simple extension of the Haken-Kelso-Bunz
(1985) model.,