Ever wonder how a major league baseball player hits a 90-mph fastball? Ask some researchers at UC Berkeley, who have identified an area of the brain that makes it possible.
Look at the numbers alone and hitting a home run seems next to impossible. A fastball takes .4 seconds to reach home plate after it leaves a pitcher’s hand, but a hitter needs a full .25 seconds to see the ball and react.
“Light hits our eye and the information needs to get to our brain,” said researcher Gerrit Maus of UC Berkeley. “That takes a tenth of a second. After that we make a decision to move, and that signal needs to get to our muscles.”
Maus said it’s an example of a fundamental problem: “Everything our brain receives is actually already out of date by the time the information gets to the brain.”
Luckily, the brain compensates for that lag time. Based on the movement of the object and the background behind it, the brain makes a projection of where the object will be. In a scientific paper released today, Maus and colleagues identified an area of visual cortex where that happens.
“If we didn’t have the prediction mechanism going on, then you would see the ball possibly 3 or 4 yards behind where it actually is,” Maus said.
“It’s not only important for baseball or tennis, but also in everyday life. For example, when we’re driving, we would always think we’re not as far down the road as we actually are.”
While we might think we’re seeing the world as it really is, Maus said what we’re actually seeing is just a calculation.
“It’s really the fundamental question of what we perceive,” he said. “We don’t see what’s coming in through the eye, but we see a story that the brain makes up for us to be able to interact with the world. It’s a very sophisticated system, but it doesn’t always show us everything as it is.”
The ultimate goal of the work is to broaden our understanding of how the visual system functions.
“For one thing, we’re trying to build artificial systems that see like a human does,” Maus said. “Ever since engineers have tried this, they’ve understood it’s a really hard problem. The other application would be basic medicine – we need to know how something works before we fix it.”