The Secret of the Curve Ball

Ever wondered why its so tricky to hit the curve ball in baseball? Well, this example might just show you why. Big news is that three best visual illusions in the world were chosen last weekend, at a gathering of neuroscientists and psychologists at the Naples Philharmonic Center for the Arts in Florida. We’ve been reporting about the annual competition each year, and this year’s winning submission was created by Arthur Shapiro, a Bucknell University professor.

A properly thrown curve ball spins in a way that makes the air on one side move faster than on the other. This causes the ball to move along a gradual curve. From the point of view of a batter standing on home plate, though, curve balls seem to “break,” or move suddenly in a new direction. This year’s winning illusion may explain this phenomena. Arturo’s animation shows a spinning ball that, when watched directly, moves in a straight line. When seen out of the corner of the eye, however, the spin of the ball fools the brain into thinking that the ball is falling towards the left. We had another VERY SIMILAR example posted few months ago.

So, as a baseball flies towards home plate, the moment when it passes from central to peripheral vision could exaggerate the movement of the ball, causing its gradual curve to be seen as a sudden jerk. Be sure to observe the falling ball directly, and indirectly (from aside) while reading the text embedded inside the animation. See the difference? Other winning illusions will be posted shortly. More can be found here.