Researchers Say Curveball An Optical Illusion
SAN FRANCISCO (CBS 5) -- On Saturday, Giants ace Tim Lincecum takes the hill in Game One of the National League Championship Series against the Phillies.
In his arsenal: fastballs, changeups, sliders, and curveballs: pitches designed to confuse batters.
The approaching ball appears to defy gravity to break, drop or do a whole range of unusual behaviors. Well, not so fast.
California researchers are now throwing us a new curve. They say the distinctive break of a curveball is nothing more than an optical illusion.
Dr. Zhong-Lin Lu of the University of Southern California said curveballs really do curve, but that the sharp break occurs when the batter shifts his eye between his central and his peripheral vision.
He said when the ball leaves the pitcher's hand that the batter focuses on the ball using his central vision. When the ball is about 20 feet away from home plate, the batter tends to switch to his peripheral vision.
Finally, as the ball arrives at the plate, the batter switches back to his central vision, and sees the ball in a different spot than expected.
Dr. Lu did his research with Dr. Arthur Shapiro of American University. The study is published in PLoS One, a peer-reviewed online publication hosted by the Public Library of Science.
To see the optical illusion, go to: http://illusioncontest.neuralcorrelate.com/2009/the-break-of-the-curveball/
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