It's an old debate: Does the curveball really bend, or is it just an illusion, like the river that runs uphill at Marshy Hope? Both says Arthur Shapiro, Associate Professor of Psychology at American University in Washington DC. Shapiro's demonstration of the illusory component won the Neural Correlate Society's Best Illusion of the Year Contest. In the game of baseball, a pitcher stands on a mound and throws a 2.9-inch diameter ball in the direction of home plate. The pitcher creates different types of pitches by releasing the ball at different velocities and with different spins. A typical major league “curveball”...