The cognitive capacities of infants are evident in the way they use reaching to manipulate and explore their environment. Infants demonstrate considerable capacity to adjust their reaches to different tasks, and to use particular strategies to solve particular tasks. At present it is not clear why infants use particular ways of reaching in different situations, or why the kinematics of reaching changes so dramatically during development. The present proposal suggests that infant reaching kinematics are mainly determined by the internal constraints imposed by the infant's lower-level motor systems and by the external constraints imposed by the task. The current proposal suggests that infant motor planning can be modelled as the development of a plan to control a stochastic dynamical system representing the lower-level motor systems. This formulation of the planning problem, together with a small number of testable assumptions, predicts motor behaviors, and spotlights the aspects of the reach that are most important in controlling the arm, and guides experimental design. The proposed research examines the kinematics of infant reaches in several tasks and compares the infant's movements with movement plans predicted by a mathematical model. The research tests whether adults will adopt infant-like strategies when forced to execute movements with a model of the infants lower-level motor systems.
