Innovation catches curveball illusion

Perhaps EDN should add an “Illusion of the Year” category to its annual innovation awards. The Vision Sciences Society presents one, and according to the Fast Company Design & Innovation blog, this year’s award went to a demonstration relating to the curveball (a type of pitch thrown in baseball).

The curve of a curveball occurs because of top spin. What’s not been clear is why the curve, which is gradual and consistent over the flight of the ball, appears to a batter to be sharp and nearly instantaneous. Award winners Arthur Shapiro, Zhong-Lin Lu, Emily Knight, and Robert Ennis have demonstrated that the apparent sharp break results when the batter’s view of the spinning ball switches between foveal to peripheral vision. An animation demonstrates the illusion, allowing you to adjust pitch speed and rotation.

Second prize went to an experiment involving afterimage colors. Third prize went to a demonstration that suggests difficulty for gender-recognition software (used, for example, to demonstrate that the Mona Lisa is not a self portrait or to deliver gender-appropriate content)—it turns out that a simple shift in contrast can affect people’s determination of gender.