The Misperception: You see everything going on before your eyes, taking in all the information like a camera.
The Truth: You are only aware of a small amount of the total information your eyes take in, and even less is processed by your conscious mind and remembered.
Magicians build careers around inattentional blindness.
It takes just a smidgen of misdirection to conceal a change in your visual field. Innattentional blindness is literally looking without seeing. It turns out, your brain isn’t a passive receiver of your eyes. Instead, you actively participate, choosing what to perceive and greatly overestimate in hindsight what you’ve committed to memory.
You are familiar with focusing attention on sounds. For instance, at a party you can listen to a single person talk while a cacophony of voices and music bounces around the room. You tune out sounds all the time at work, in a city, watching television, turning down the volume on what you aren’t interested in – but you don’t notice it as much when you do it visually.
You are “blind” to that which you are not attentive. As events unfold before you, you tend to pay attention to a small cone of information and then, when thinking back on what you saw, you tend to believe you saw more than you did. Consciousness is all about filling in the gaps. You assume you know what’s happening right outside whatever it is you are focused on, but all over the place, you are imagining the things you can’t see.
So, when you form a memory, and then later recall that memory, anything which wasn’t captured by your attention might be a fabrication – a dream. Inattentional blindness can also come about from an overload of visual information, all of it considered important, but all of it familiar. As Christopher Chabris and Daniel Simons point out in their book, The Invisible Gorilla, experienced pilots are often less likely to see a plane on a runway than pilots who have only landed a handful of times. Experienced doctors may have a harder time diagnosing a peculiar disorder than a fresh-from-medical-school physician.
When it comes to seeing everything you’re looking at – you are not so smart.