Keep your eye on the ball, the curveball is just an illusion
If you’ve ever tried to hit a curve ball you can probably attest to it being one of the most difficult things to do in sports. The idea being that the ball is suddenly breaking as it nears the plate. A batter anticipates the location of the pitch, and swings
for it, only to have the ball duck under the bat. However according to research released Wednesday in the journal PLoS One, scientists are refuting that idea, claiming that there is no break, that the appearance of a curve is nothing more than an optical illusion.
What advice can you give a batter with this new piece of information? Only the most commonly heard piece of advice batters have been listening to for decades, ‘keep your eye on the ball.’
According to researchers Arthur Shapiro of American University, and Zhong-Lin Lu of the University of Southern California the ball follows a smooth arc from the pitcher’s hand to the catcher’s mitt.
"The curveball does curve, but the curve has been measured and shown to be gradual," Shapiro said. "It's always going to follow a parabolic path. But from a hitter's point of view, an approaching ball can appear to break, drop or do a whole range of unusual
behaviours."
Despite the fact that curve balls don’t curve the way many of us thought, Major League hitters have been striking out on curveballs for about as long as baseball has been around. Something is causing these professional hitters to miss the ball.
The illusion is an effect caused by the human eye. Our central vision has about a two degree field of view. Anything outside of this two degree field is in our peripheral vision. When a batter watches the ball come out of the pitchers hand he sees it in
his central vision, by the time the ball is about 20 feet from home plate the ball is in his peripheral vision.
"The break of the curveball is not consistent with physics and people have suspected that it might be a perceptual illusion," said Lu. "It demonstrates a major difference between central and peripheral vision. If you take your central vision of the ball,
the periphery vision gets confused and can’t separate the signals. You combine them.”
The theory is that the two different types of vision create the illusion of a ‘breaking ball’. The experiment to prove it had five observers stare straight at a circle in a flash animation. The circle then fell straight down on the screen. To the observers
it looked like the circle fell in a straight line. When they were told to focus to the side of the screen and pay attention to the circle, it looked as though it fell at an angle, even though it was still falling straight down.
It sounds simple to just adjust your vision to compensate, but consider that two time Cy Young award winner, Tim Lincecum, throws a curve ball 80 miles an hour. It takes less than a second for the ball to travel the 60 feet 6 inches from the mound to the
plate. Any imperfection in a person’s vision is going to have drastic results. In this case it’s a wild swing, often well off the mark.
"We tell players to keep their eye on the ball, but you just can't," said Rob Gray, a psychology professor at Arizona State University. "It is physically impossible to follow a major league baseball all the way to the plate."
Saturday’s game between the Philadelphia Phillies and the San Francisco Giants, Game 1 of the National League Championship Series, will provide an abundance of examples of the curveball in action. Lincecum will take on another Cy Young award winner, Roy
Halladay, in what is arguably a battle between the two best pitchers in baseball. There is no doubt that curveball use will be in full swing with these two going head-to-head.
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