For millions of fans, Willie Mays’ graceful catch of a deep fly ball to the outfield was a work of art, a moment to savor.
But scientists now say the “Say Hey Kid” really was adopting an “error-nulling tactic” by “selecting a running path that maintains a linear optical trajectory for the ball.”
With the major-league season finally getting under way last week, a research study published Friday sheds new light on the instinctive skill of catching a fly ball. The researchers conclude that a good outfielder uses a predatory tracking method like that of a fish swimming toward its food.
And take heart. With practice, just about anyone can do a decent job of shagging flies, the researchers say. Even amateur players seem to know from the first crack of the bat where to head.
Why? Easier done than explained.
The researchers propose that a good outfielder maneuvers so a hit ball always appears to travel upward in a straight line relative to home plate and the background scenery. The player adjusts his speed and direction to keep a mental image - or “linear optical trajectory” - in which the ball does not curve down. Even in the last seconds before a catch, the ball appears to the player to be straight above.
The researchers - psychologists Michael McBeath and Dennis Shaffer at Kent State University in Ohio and Mary Kaiser of the National Aeronautics and Space Administration’s Ames Research Center in California - videotaped the tracks followed by college students who shagged a series of fly balls. The students’ paths proved to have a slight curve. Studies of tracking behavior by fish and houseflies have shown similar curved paths, McBeath said. Outfielders go for flies as hunting animals go for prey, McBeath said.
The new analysis, published in the weekly journal Science, emphasizes players’ ability to follow spatial cues rather than their skill in judging subtle changes in the speed of the hit ball, as others have argued.
The new study will not become a dugout classic. The closest it comes to a coaching tip: “When a fielder must run to the side and change depth, he or she can maintain a constant decrease in the tangent of the lateral optical angle … by leading the ball somewhat (scaling his lateral running speed to his distance from home plate.)”
Still, Joe Diestel, a Kent State mathematician and amateur baseball coach, said the finding about curved paths rings true. Coaches often tell young players “when tracking a fly ball, circle to cut off the gap” as the ball approaches, Diestel said.
McBeath and his colleagues acknowledge their research will have little impact in the big leagues. “I think a lot of professional players are appropriately hesitant” about analyses of their skills, Kaiser said. “If we mess with their heads too much they won’t do what they do so well.”
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