Abstract
Good vision is paramount for a large variety of tasks such as taking a swing in baseball. One of the ways in which we achieve good vision is by moving our eyes. I will describe a set of psychophysical experiments showing that smooth pursuit eye movements improve motion perception in healthy adults. I will also discuss experiments in schizophrenia patients with motion perception deficits, where eye movements did not have beneficial effects on perception. Recently, we have extended this paradigm to examine the effect of eye movements on hand movements in a rapid interception task. We tested 32 varsity baseball players who tracked a small moving dot, back-projected onto a translucent screen, and intercepted it with their index finger in a designated hit zone. Only the first part (100–300 ms) of the trajectory was shown and observers had to extrapolate and intercept the assumed dot position anywhere within the hit zone. Better smooth pursuit resulted in more accurate interceptions. A Hazard analysis yielded two interception strategies: early interceptors relied on feedback given at the end of each trial whereas late interceptors depended on tracking accuracy. A regression model identified low tracking error and small catch-up saccades as best predictors of interception accuracy. These results may guide the development of vision training protocols for sports and clinical rehabilitation.