The perceptual illusion of baseball's rising fastball and breaking curveball

A. Terry Bahill, William J. Karnavas
1993 Journal of Experimental Psychology: Human Perception and Performance  
The rising fastball and the breaking curveball are impossible according to principles of physics and physiology, yet many baseball players claim they exist. The simulation and model presented suggest that the rising fastball and breaking curveball are perceptual illusions caused by the batter misestimating the speed of the pitch. This model uses signals from known primary visual processes only. This model was enhanced by adding an acceleration term. The enhanced model more accurately predicts
more » ... curately predicts the position of the ball when it crosses the plate. These models are compared and contrasted to models by McBeath and Bootsma. Sensitivity analyses have shown that the model and simulation are robust with respect to their parameter values. The model is most sensitive to the estimated distance to the ball, and the simulation is most sensitive to the estimated speed of the pitch.
doi:10.1037//0096-1523.19.1.3 fatcat:i6zfkwqn6rfjviamaefwslewma