Close one eye and focus straight ahead without moving your eyes. In your peripheral vision—in your nose—you notice a fleshy smudge. It is there in every waking moment, but you are hardly ever aware of it. So why can’t we see our noses, even though they are literally right in front of us?
“You can look at your nose,” he said Michael Webstervisionary and co-director of the neuroscience program at the University of Nevada, Reno. We just don’t realize it most of the time.
“Vision is actually a prediction of what you think the world is,” Webster said. “Do you want to be aware of how the world is different?” “What are the surprises and mistakes and things I didn’t foresee?” Normally you are not aware of your nose because you already know about it and you just don’t want to be aware of it. … It is a great disadvantage to waste a little energy on it.”
This makes sense in terms of survival; constantly processing fixed features like your nose would be a waste of limited mental resources when you need to detect threats, find food, or navigate your environment. In fact, your brain cancels out all kinds of information about your own body to help you perceive the outside world.
Take the blood vessels of the eyes for example. Photoreceptors, which collect light from the outside world, are located at the back of the eye, behind a tangle of blood vessels.
“It’s like you’re sitting in a tree made of dead branches and you’re actually seeing the world through all these dead branches,” Webster said.
Your brain will usually cancel this out, but there are ways to make your eye’s blood vessels appear so your conscious mind can see them. If you’ve ever had an eye exam, you may have noticed dark ripples in your vision when the optometrist shined a light through your eye. These are the shadows cast by the blood vessels of your eyes.
Your brain doesn’t just cancel out unwanted information—it sometimes creates information from scratch. Take your blind spot: the empty area in your vision that corresponds to where the optic nerve leaves the eye. Your blind spot is probably 5 degrees in widthor more than twice the size of the full Moon in the sky. Yet we are usually unaware of this huge gap in our vision.
“We’re actually filling in that information,” Webster said. “Instead of seeing an absence, we have clues from what’s around the blind spot that tells us, ‘OK, if I’m looking at a white paper, it’s very likely that the part that’s in the blind spot is also white.’
It’s even easier to be aware of your nose—in fact, you may be hyperaware of it right now simply by thinking about it.
“If you really consciously try to see something, then you become aware of it,” Webster said.
Our “disappearing” noses reveal something profound about how we experience reality: Our vision is not like a camera recording what’s really there; it is more like an artist creating a model of the world that is most useful to us.
Webster took this idea even further. We may not perceive reality at all. “Even the model itself is really just the information you need. It doesn’t really tell you what the reality of the world is.”
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