Motor Skills Laboratory

Have you ever wondered how effective it is to physically guide a person through an action? In sports, the instructor might hold a person's arm to show them how to hit a golf ball or strike a volleyball serve. In rehabilitation, robotic devices are used to guide a person's limb for therapy purposes. What we and others have shown is that this technique is useful when applied, but that it compromises learning once it is removed. In this study, people practised a novel, two limb coordination movement. The task was to track with the arms two metronomes that dictated the correct rhythm (this task is often considered conceptually similar to juggling, or patting your head whilst rubbing your stomach). In one condition their arms were passively moved through the motion by robotic arms. In a second condition, we added weights to one arm to encourage the correct rhythm. In two control conditions, participants practised without guidance or just watched. The robotic guidance group did not remember very well when tested without the robot arms. They were, however, slightly better than a group who just watched. The two best groups actively practiced. The weight, therefore, was helpful in bringing about the correct movement and retaining this movement once it was removed. In this condition, weighting a limb helped in practice and importantly, it did not prevent the learner from remembering the action. We concluded that sensory experiences alone (seeing, hearing or merely feeling what is correct) have limited benefits in the early acquisition of novel movement patterns. It is important to be actively involved in the learning process.