Motor control in children and adults during a non-speech oral task.

Although decreased accuracy and increased variability of movement is a common developmental finding, the nature of these performance patterns remains poorly understood. The present study examined the accuracy and stability of several aspects of oral motor control. Specifically, we examined the control of absolute timing (temporal parameterization), absolute amplitude (amplitude parameterization), and relative timing and amplitude (generalized motor programs) in children and adults during a lip plus jaw opening and closing task. As was the case with similar reports, we found that children were both less accurate and less stable in their assignment of temporal and amplitude parameters. However, we further found that although children's underlying movement patterns were less accurate than those of adults, children exhibited similar variability in their generalized motor programs. The results are discussed within the framework of a schema model of motor control (Schmidt, 1975) with reference to the strategic allocation of resources during motor learning (e.g., Clark & Robin, 1998).