Persistance of Vision and its change during time

Persistance of vision is a commonly accepted yet controversial theory which states that the human eye always retains images for a fraction of a second. This phenomena is widely believed in film and video to account our ability to percieve a sequence of frames as a continous moving picture, which actually makes sense if we take this theory as correct but, because it has not been proven it was replaced in the 1912 by the apparent movement(an optical illusion), which is the union of beta movement and phi phenomenon