By Linda Conlin, Pro to Pro Managing Editor
When Hall of Fame baseball player Willie Mays passed away on June 18, much attention was given to what is considered to be one of the greatest plays of all time, known simply as “The Catch.” It was the eighth inning of Game 1 of the 1954 World Series in which Mays and the Giants swept the Cleveland Indians (now the Guardians) in four games. The score was tied 2-2 when Mays made an over-the-shoulder catch of a ball that traveled 421 feet from home plate, at an approximate speed of 106 mph off the bat. Mays ran 90 feet with his back to the ball, and a couple glances over his shoulder to track it. But he didn’t look at the ball for the last 20 feet before making a perfect catch over his left shoulder. How did Mays do that?
One theory is a perceptual motor skill known as optical acceleration cancellation, which Mays claimed to have learned playing football in high school. Optical acceleration cancellation proposes that that the outfielder tracks the elevation angle of the ball after it is hit. If the angle accelerates, the ball will land behind the ballplayer; if it decelerates, the ball will land in front. The fielder moves forward or backward to compensate. Researchers at Brown University tested that theory against two others, the mental model of trajectory in which outfielders rely on subconscious internal models of the physical world to calculate the ball's trajectory and predict its landing point, and linear optical trajectory, in which outfielders run in such a way that their visual image of the ball appears to form a straight line. (http://news.brown.edu/pressreleases/2010/01/flyball)
Eight varsity baseball players and four varsity softball players took part in the study, fielding virtual fly balls in Brown's Virtual Environment Navigation Lab. Each wore a head-mounted display that allowed them to see the virtual ball as it was launched, and they ran in the 40-by-40-foot research space to make their virtual catches. Their movements were consistent with the optical acceleration cancellation theory. Conducting the research virtually allowed Warren and the team to test the three theories by making the ball fly on a physically impossible trajectory. They then recorded the subjects' head and glove positions to figure out how they were trying to catch the ball. While all three models can predict successful catches and similar running paths, the digitally altered or physically impossible trajectories included in this research show that baseball players continuously track the ball and run forward or backward to cancel optical acceleration.
Broadcaster for NBC Jack Brickhouse was calling the game when Mays made that impossible catch. Brickhouse said, “Mays just brought this crowd to its feet with a catch which must have been an optical illusion to a lot of people!” But we know Mays’ perceptual motor skills were no illusion.
