Most baseball coaches and a few parents have learned the futility of instructing a young batter to “keep their eye on the ball.” Studies have shown that it is very difficult, if not impossible, for human eyes to track the trajectory of the pitch all the way across the plate. Even at the slower speeds of Little League pitchers, the shorter distance to the plate forces batters to pick-up early cues of the ball’s flight and speed, then make predictions of where and when it will cross the plate. With less than a half second to to make the swing/no-swing decision, if the muscle activity isn’t triggered early in the pitch, the bat just won’t get around in time.
This time lag between incoming visual stimuli, motion planning in the brain and activation of the muscles, known as sensorimotor delay, is common throughout sports. Think about a goalkeeper moving to stop a hockey puck or soccer ball; a tennis player returning a blistering serve; or a receiver adjusting to the flight of a football. Their eyes tell them the speed and path of the object they need to intercept, then their brain instructs the body to move in the predicted path to arrive just in time.
University of Louisville researcher Bart Borghuis, Ph.D. recognized this skill in the lowly salamander when hunting flies. To catch a passing fly with its tongue, the salamander has about 230 milliseconds to see, compute and strike. Of course, just like that fastball, the fly’s path has to be estimated so that the tongue arrives at the exact millisecond required.
Dr. Borghuis, an assistant professor in the Department of Anatomical Sciences and Neurobiology, captured 270 salamander kills using very high-speed (4000 fps) video to understand exactly how they are able to achieve a 90% success rate when targeting flies.
From his video analysis, he was able to develop an algorithm to predict the exact path and strike point of the salamander’s tongue. Sure enough, his algorithm was successful in predicting future targets except when the fly changed its course just as the tongue had fired. Sound familiar in baseball? If a batter identifies a pitch as a fastball but it turns out to be a slider, the positioning of the bat swing will be off just enough for a swinging strike. Similarly, if the hitter expects a change-up, the timing of her swing will be off if it’s actually a fastball.
The research has been published in the Journal of Neuroscience.
"The misses confirmed the model," said Dr. Borghuis. "This is the first demonstration that the salamanders were making a prediction. This information adds to a small set of clear examples of how vertebrates -- including humans -- use prediction for dealing with delays in motor processing. Now that we know how the salamander does this, we can further investigate the neuromechanisms that make this happen."
Training a young hitter’s eyes and brain to identify the type of pitch early after its release will help them make intelligent guesses as to its future flight. While they may not see the ball hitting the bat, they will have fun watching it sail into a gap on the field.