What is Change blindness?
Change blindness is the failure to detect significant visual changes in a scene, even when they occur in plain sight. It reveals that visual perception is far less complete than subjective experience suggests.
How it works
Simons and Chabris (1999) demonstrated change blindness dramatically with the ‘invisible gorilla’ experiment: participants counting basketball passes failed to notice a person in a gorilla suit walking through the scene. Change blindness occurs because visual awareness depends on attention, and attention is selective. We see far less of our environment than we believe we do. The phenomenon has practical implications for interface design, security monitoring, and eyewitness testimony.
Applied example
A driver who is focused on the car ahead may fail to notice a pedestrian stepping into the crosswalk, even though the pedestrian is clearly visible. The driver was attending to the car, and change blindness prevented detection of the pedestrian entering the visual field.
Why it matters
Change blindness reveals that attention, not vision, determines what we perceive, with critical implications for safety, design, and the reliability of human observation.
