“Why We Miss Objects That Are Right in Front of Us”
“In particular, the first time a person examined a photo with a giant object, the object often seemed to be invisible. But it’s not a deficiency, he said: “This is a useful trick the brain does to rapidly process scenes and find what we are looking for.”
It is unlikely, in real life, that you’ll be required to find many giant objects.
But a related phenomenon may be to blame for your struggle to see your keys if they are not where you normally put them, or for your tendency to notice stains more on one colleague’s shirt than on another’s.
“What we pay attention to is largely determined by our expectations of what should be present,” said Christopher Chabris, a cognitive psychologist and co-author of The Invisible Gorilla.
Relative size is just one of many pieces of information that contribute to our expectations. Without expecting something, we’re unlikely to pay attention to it, he says, and “when we are not paying attention to something, we are surprisingly likely to not see it.”