Change blindness is a perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer does not notice it. For example, observers often fail to notice major differences introduced into an image while it flickers off and on again
People’s poor ability to detect changes has been argued to reflect fundamental limitations of human attention. Change blindness has become a highly researched topic and some have argued that it may have important practical implications in areas such as eyewitness testimony and distractions while driving.
Outside of the domain of psychology, phenomena related to change blindness have been discussed since the 19th century. When film editing was introduced in movies, editors began to notice that changes to the background were not noticed by those watching the film. Going back earlier, William James (1842–1910) was the first to mention the lack of ability to detect change in his book Principles of Psychology (1890).