Abstract
Background: Coordinated rhythmic movement is specifically structured in humans. Movement at 0° mean relative phase is maximally stable; movement at 180° is less stable; and no other relative phase is stable without training. Previous work has demonstrated this pattern in perceptual judgment tasks, and also that perceptual feedback manipulations affect movement stability. These results are seen as evidence that perception plays a key role in determining the coordinated movement stabilities.
Methods: Stable movement at other relative phases (e.g. 90°) can be acquired through practice of the movements. We investigated whether such stable movements can be acquired through perceptual learning. We first assessed Baseline movement stability at 0°, 90° and 180° by having participants use a joystick to coordinate the movement of two dots on a screen at the three phases. Perceptual stability at 90° and 180° was assessed with a 2-alternative forced choice (2AFC) task in which participants identified the target phase from a pair of displays. Participants then practiced to improve their perceptual resolution of 90° by making progressively harder discriminations, with feedback. We then assessed movement and perceptual stability in Post Training and Retention sessions.
Results: Improved perceptual discrimination of 90° immediately led to improved performance in the 90° movement task without any motor training. The improvement persisted between Post Training and Retention without further task exposure. Movement stability at 90° for a control group (movement assessment only) did not improve.
Conclusions: Movement stability is a function of perceptual stability - improving the latter improves the former. Perceptual information is an integral part of the organization of this dynamical system.