Catching fly balls: A simulation study of the Chapman strategy

Abstract

Chapman [Chapman, S. (1968). Catching a baseball. American Journal of Physics, 36, 868–870] showed that a catcher may be guided to the landing spot of a fly ball by zeroing out its optical acceleration. Subsequently, various studies have provided evidence for what is now known as the Chapman strategy. However, in those studies the catcher’s own acceleration and the visuo-motor delay were ignored. This raises the question whether the Chapman strategy still provides an accurate description if those factors are taken into account. To address this question, we implemented the Chapman strategy in a forward dynamical model of the catcher’s locomotion in relation to the ball’s actual trajectory. Numerical simulations of the model revealed that catching performance was still successful under a broad range of ball trajectories. Furthermore, the model simulations largely reproduced the real running paths reported by McLeod and Dienes [McLeod, P., & Dienes, Z. (1996). Do fielders know where to go to catch the ball or only how to get there? Journal of Experimental Psychology: Human Perception and performance, 22, 531–543]. However, the simulations also revealed that real running paths exhibit some detailed characteristics that appear to be irreconcilable with the Chapman strategy.