Fagg, Barto & Houk: Learning to Reach via Corrective Movements; Tenth Yale Workshop on Adaptive and Learning Systems Learning to Reach via Corrective Movements
When infants begin to perform goal-directed reaching between approximately 4 and 5 months-of-age, the kinematics of their reaches show multiple accelerations and decelerations of the hand, which appear to reeect a correcting series of submovements. Although each sub-movement is an inaccurate correction, the sequence of submovements is often successful in reaching the target. By what process does the infant's reach controller come to eventually produce adult-like reaching behavior, characterized by bell-shaped velocity prooles and only occasional corrections? We suggest that motor command parameters are tuned in a supervised learning fashion using training information derived from proprioceptive feedback received during corrective movements. Although this is not high-quality training information, it is suucient to tune motor command parameters in order to bring a dynamic arm quickly and accurately to the target, as we show in a series of simulations. We also suggest that additional parameters can be tuned to satisfy constraints other than end-point constraints through a reinforcement learning process.