To see or not to see: The need for attention to perceive changes in scenes

When looking at a scene, observers feel that they see its entire structure in great detail and can immediately notice any changes in it. However, when brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: Identification of changes becomes extremely difficult, even when changes are large and made repented!v. Identification is much faster when a verbal cue is provided showing that poor. visibility is not the cause of this difficulty. Identification is also faster for objects considered to he important in the scene. These results support the idea that observers never for in a complete, detailed representation of their surroundings. In addition, the results indicate that attention is required To perceive change, and that in the absence of localized motion signals, attention is guided on the basis of high-level interest.