How the Brain Perceives a 100 Mile Per Hour Fastball

By Wesley Fenlon

It takes so long for a signal to travel between our eyes and our brain, the visual cortex has to do some tricky processing to predict where that object will be a split-second later.

It takes a very special baseball pitcher to throw a 100 mile per hour fastball. 90 miles per hour? That's a breeze. 95? A whole bunch of them can do that. But when you top 100 miles per hour, the list thins out. Experts estimate that baseball legend Nolan Ryan threw the fastest pitch of all time--108 miles per hour--in 1974. There's a reason Ryan and fellow blazing-fast-fastball pitcher Randy Johnson own the top two spots on the all-time strikeout leaderboard: It's really tough to track, much less hit, something moving at 100 miles per hour.

Photo credit: Flickr user sidehike via Creative Commons.

There's science to back that up. There’s a 100 millisecond delay between the moment your eyes see an object and the moment your brain registers it," writes Surprising Science. "As a result, when a batter sees a fastball flying by at 100 mph, it’s already moved an additional 12.5 feet by the time his or her brain has actually registered its location."

Some researchers at Berkeley decided to find out. They put subjects through an fMRI to figure out which parts of the brain are responsible for predictive vision. A summary of the study's results says "Findings suggest that the middle temporal region of the visual cortex known as V5 is computing where moving objects are most likely to end up."

The researchers used the test below, which uses a moving background to trick the brain into thinking a stationary object is sliding around.

Here's what's happening when you watch that video:

"The brain interprets the flashes as part of the moving background, and therefore engages its prediction mechanism to compensate for processing delays...The researchers found that the illusion--flashes perceived in their predicted locations against a moving background and flashes actually shown in their predicted location against a still background--created the same neural activity patterns in the V5 region of the brain. This established that V5 is where this prediction mechanism takes place."

Thanks to the V5, our brains compensate for the delay between when our eyes see something and when that signal reaches the brain. It lets us--at least a few of us--track fastballs accurately enough to hit them, even when they're traveling at 100 miles per hour. Of course, there are other benefits, like being able to drive at high speeds, or just processing motion in general. Thanks, visual cortex!