Flawed assumptions. In my last post, I proposed an experiment to test whether or not the flash-lag illusion might be at work in mistaken calls made by baseball umpires (like the one made by Jim Joyce that cost Armando Galarraga a perfect game). In this, I proposed that a batter running toward first base presents the moving stimulus, and the ball hitting the glove of the firstbaseman (or pitcher as the case may be) represents the instantaneous, or flash, stimulus. However, it occurs to me that it may be just as likely that an umpire might track the incoming throw, and thus the baseball would be the moving stimulus, while the runner’s foot hitting the base would become the “flash” stimulus. Since these variables can be so easily reversed, it is likely that the involvement of the flash-lag effect would not necessarily be revealed by any differences in the proportion of errors where the runner was called “safe” versus those where he was called “out”. What we would need to do is to get umpires who would volunteer to wear head-mounted cameras so that we could know which object they were tracking (or which one they track most often), the runner or the baseball. Granted, this makes the experiment more difficult, but it is not much different from what was done in this study, which could be claimed as the study that initiated the whole discussion on the potential role of the flash-lag effect in sports officiating.