Universal Principles of Design, Updated and Expanded Third Edition

097 Inattentional Blindness

A failure to perceive an unexpected stimulus presented in clear view.

When people are focused intently on performing a task, roughly 50% of them will be functionally blind to stimuli that are unexpected and unrelated to the task. Functionally blind means that the eyes see, but the brain does not process the visual inputs. For example, in 1972, an Eastern Airlines cockpit crew noticed that a landing gear indicator failed to illuminate. They became so fixated on the cause that they failed to notice their loss in altitude or respond to ground alarms. The resulting crash killed more than 100 people. Inattentional blindness is one reason talking on the phone (even a hands-free phone) while driving is unsafe—the eyes may ...