Mind Hacks

Hack #17. Glimpse the Gaps in Your Vision

Our eyes constantly dart around in extremely quick movements called saccades. During each movement, vision cuts out.

Despite the fact that the eye has a blind spot, an uneven distribution of color perception, and can make out maximal detail in only a tiny area at the center of vision, we still manage to see the world as an uninterrupted panorama. The eye jumps about from point to point, snapshotting high-resolution views, and the brain assembles them into a stunningly stable and remarkably detailed picture.

These rapid jumps with the eyes are called saccades, and we make up to five every second. The problem is that while the eyes move in saccade all visual input is blurred. It’s difficult enough for the brain to process stable visual images without having to deal with motion blur from the eye moving too. So, during saccades, it just doesn’t bother. Essentially, while your eyes move, you can’t see.

In Action

Put your face about 6 inches from a mirror and look from eye to eye. You’ll notice that while you’re obviously switching your gaze from eye to eye, you can’t see your own eyes actually moving—only the end result when they come to rest on the new point of focus. Now get someone else to watch you doing so in the mirror. They can clearly see your eyes shifting, while to you it’s quite invisible.

With longer saccades, you can consciously perceive the effect, but only just.

Hold your arms out straight so your two index fingers are at opposite edges ...