How could they miss something right before their eyes? This form of invisibility depends not on the limits of the eye, but on the limits of the mind. We consciously see only a small subset of our visual world, and when our attention is focused on one thing, we fail to notice other, unexpected things around us—including those we might want to see.
(Daniel J. Simons)
Article from the Smithsonian Magazine: ‘But Did You See the Gorilla? The Problem With Inattentional Blindness‘.