Inattentional blindness

Inattentional blindness is a psychological lack of attention that is not associated with any vision defects or deficits. It is best illustrated by this quote, used frequently within Cognitive Edge:

“24 radiologists were asked to perform a familiar lung nodule detection task.

A picture of a gorilla, 48 times larger than the average nodule, was inserted in the last case.

83% of radiologists did not see the gorilla.

Eye-tracking showed that the majority of the those who missed the gorilla looked directly at it”

Drew, Vo & Wolfe 
 Psychol Sci. Sep 2013; 24(9): 1848–1853