You Have a Visual Speed Limit Linked to Your Eye Movements

If you’ve ever shaken your head around and not vomited from the nauseating blurring of your vision, it’s because your brain has a built-in mechanism called saccades that it uses to not show you the blur.

It’s a neat little magic trick that your brain and eyes pull off, the details of which are explained in a new study in Nature Communications. The speed of your eye movements actually determines how fast something has to be moving before you can’t see it anymore.

People with faster saccades can catch more action before it disappears into a motion-invisibility grey area. That means your ability to see a baseball pitch or a bird taking off depends on your eyes’ ability to see fast motion. It could be completely different for somebody else.

Lead researcher Martin Rolfs from Humboldt University explains that it’s not just the inner workings of your eye that set your vision’s limits, but the way your body moves also has some say in the matter. When your eyeballs track something moving at the same speed and direction as your saccades, it becomes invisible. Your brain just assumes that it isn’t important.

This crossover between motion and perception means that our sensory system is built with our movement system, not separate from it. Unfortunately, according to Rolfs, the scientists who study how we move and the ones who study how we see are rarely, if ever, in contact with one another. In this instance, they would make the perfect pairing, but good luck even getting them in the same room together.

The next time you find yourself struggling to catch a rapidly moving object, don’t blame the lighting. Blame your eye muscles and brain for having no idea what to do with the information they’re taking in.