Perception · about 2 minutes
The Hole in the World
There is a hole in your vision, right now, roughly the size of a grapefruit held at arm's length. You have never once noticed it. Let's go find it.
- Cover or close your left eye.
- With your right eye, stare at the teal +. Keep staring at it — no peeking at the dot.
- Start with your face about an arm's length from the screen, then slowly lean in. Somewhere along the way, the orange dot will simply stop existing.
- Can't find it? Nudge the dot with the slider and lean in again. It's there. It's always been there.
Works best on a laptop-sized screen. On a phone, turn it sideways and hold it close.
What just happened
The wiring of your eye exits through the back of the retina, and at that exact spot there are no light-sensing cells at all. Nothing. A dead zone, in each eye, covering about six degrees of your visual field — comfortably grapefruit-sized at arm's length.
Here's the part worth staring out a window about: you don't see a hole. You've never seen a hole. Your brain checks the surroundings and makes something up — confidently, seamlessly, in real time.
Which is why the wallpaper button is the real exhibit. Turn it on and find the blind spot again: the dot doesn't vanish into blackness, it vanishes into more stripes. Stripes that are not there. Your brain painted them, just now, for you, unasked.
Why it matters
You never see the world raw. You see your brain's best-guess rendering of it — well-tested, mostly reliable, and demonstrably willing to invent wallpaper. Every exhibit in this museum stands on this one fact: the show you're watching is produced in-house.
Take it further
V.S. Ramachandran's filling-in experiments are a delight — he got blind spots to swallow whole faces. Anil Seth's phrase for all this is that perception is a "controlled hallucination" — hallucinating, but on a leash held by your senses.