ABSTRACT
This chapter examines the hand-movement trajectories that occur in response to a new ball trajectory. A ball attached to the top of a physical pendulum rotates around a fixed axis toward the catcher. Starting from different initial hand positions, a participant is asked to catch balls approaching different final positions at different incidence angles. The VITE model modification proposed by Michaels et al. (2004) was used to simulate hand movement trajectories, given the trajectory of the ball. The predicted trajectories show one, two or no movement reversals depending on initial hand position, and the variable that is assumed to be informative in guiding hand movements. The participants compare these predictions to observed hand trajectories. The optical variable and the hand movement are synchronized by shifting up the time series of the former by 500 ms. The optical variable appears to be guiding hand movements successfully.
