change blindness

Meaning: Change blindness is the failure to detect a change between two views of a scene, even a large one, when the change occurs during a brief disruption such as a blink, an eye movement, a screen flicker, or a film cut. Normally a sudden change produces a visual transient that draws attention. The disruption hides that signal, so the viewer must compare the two views from memory. Attention is limited and the mind does not store a detailed copy of the whole scene, so changes to unattended features often go unnoticed.

On the MCAT: A passage describes a flicker task, or a real-world study in which an experimenter is swapped for another person during a brief interruption and many participants do not notice. Questions ask you to link the result to selective attention, limited attentional capacity, or top-down processing. A typical prediction is that changes to the focus of attention are detected more readily than changes to peripheral details.

Common confusion: Change blindness is not inattentional blindness. Inattentional blindness is missing an unexpected object that is present in a scene while attention is engaged on another task (the invisible gorilla study). Change blindness is missing a difference between two successive views. Both reflect selective attention. Neither is a sensory defect, because the eyes and visual pathways are working normally.