Persistence of vision

Persistence of vision is the <a href="/facts/Optical_illusion/8wfWwjFI">optical illusion</a> that occurs when the <a href="/facts/Visual_perception/g7Tfaq2l">visual perception</a> of an object does not cease for some time after the <a href="/facts/Light_ray/PgUEC7Sm">rays of light</a> proceeding from it have ceased to enter the <a href="/facts/Eye/h3lbYU55">eye</a>. 
The illusion has also been described as "retinal persistence", "persistence of impressions", simply "persistence" and other variations. A very commonly given example of the phenomenon is the apparent fiery trail of a glowing coal or burning stick while it is whirled around in the dark.
Many explanations of the illusion actually seem to describe <a href="/facts/Afterimage/C93egAYk">positive afterimages</a> and the neurological effect can be compared to the technological effect of <a href="/facts/Motion_blur/y7jR2shk">motion blur</a> in photography (or in <a href="/facts/Film/wM3b9Kk3">film</a> and <a href="/facts/Video/F1AV8ben">video</a>).
"Persistence of vision" can also be understood to mean the same as "<a href="/facts/Flicker_fusion/Bbt0HRrk">flicker fusion</a>", the effect that vision seems to persist continuously when the light that enters the eyes is interrupted with short and regular intervals. When the frequency is too high for the <a href="/facts/Visual_system/QVcuA27K">visual system</a> to discern differences between moments, light and dark impressions fuse together into a continuous impression of the scene with intermediate brightness (as defined by the <a href="/facts/Talbot-Plateau_law/uG2kcpHW">Talbot-Plateau law</a>).
Since its introduction, the term "persistence of vision" has often been mistaken to be the explanation for <a href="/facts/Motion_perception/kShuo6b8">motion perception</a> in <a href="/facts/Optical_toys/6JP6BJjJ">optical toys</a> like the <a href="/facts/Phenakistiscope/GkD57Mzu">phenakistiscope</a> and the <a href="/facts/Zoetrope/7J1ukfFl">zoetrope</a>, and later in cinema. This theory has been disputed since long before cinematography's breakthrough in 1895. The illusion of motion as a result of fast intermittent presentations of sequential images is a <a href="/facts/Stroboscopic_effect/TpbhkP5d">stroboscopic effect</a>, as explained in 1833 by <a href="/facts/Simon_Stampfer/AH449VXC">Simon Stampfer</a> (one of the inventors of the stroboscopic disc, a.k.a. phenakistiscope).
Early descriptions of the illusion often attributed the effect purely to the <a href="/facts/Physiology/fh25y2pQ">physiology</a> of the eye, particularly of the <a href="/facts/Retina/v0ISNX2S">retina</a>. Nerves and parts of the brain later became accepted as important factors.
<a href="/facts/Sensory_memory/a18t09Hd">Sensory memory</a> has been cited as a cause.

Persistence of vision open-in-new

Persistence of vision