Monday, 1 February 2016

List of optical illusions


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This is a list of optical illusions.
Afterimage illusionAfterimagenpov.svgAn afterimage or ghost image is an optical illusion that refers to an image continuing to appear in one's vision after the exposure to the original image has ceased.
Afterimage on empty shape (also known as color dove illusion)Afterimage.svgThis type of illusions is designed to exploit graphical similarities.
Ambiguous imageDuck-Rabbit illusion.jpgThese are images that can form two separate pictures. For example the image shown forms a rabbit and a duck.
Ames room illusionAmes room.svgAn Ames room is a distorted room that is used to create an optical illusion.
Ames trapezoid window illusionAmes window.pngA window is formed in the shape of a trapezium. It is often hung and spun around to provide the illusion that the window rotates through less than 180 degrees.
Autokinetic effectThe autokinetic effect, or autokinesis, occurs when a stationary image appears to move.
AutostereogramStereogram Tut Random Dot Shark.png
Stereogram Tut Eye Object Size.png
An autostereogram is a single-image stereogram (SIS), designed to create the visual illusion of a three-dimensional (3D) scene from a two-dimensional image in the human brain. An ASCII stereogram is an image that is formed using characters on a keyboard. Magic Eye is an autostereogram book series.
Barberpole illusionBarberpole illusion animated.gifThe barber pole illusion is a visual illusion that reveals biases in the processing of visual motion in the human brain.
Benham's topBenham's Disc.svgWhen a disk that has lines or colours on it is spun, it can form arcs of colour appear.
Beta movementPhi phenomenom no watermark.gifMovement that appears to occur when fixed pictures turn on and off.
Bezold EffectBezold Effect.svgAn apparent change of tone of a colour due to the alteration of the colour of the background.
BlivetPoiuyt.svgAlso known as "poiuyt" or "devil's fork", this illusion is an impossible image because in reality the shape cannot exist.
Café wall illusionCafé wall.svgThis illusion is a pattern where different coloured squares on a wall appear to form horizontal curved lines. It is named such because this is the type of artwork often seen on café walls.
Catoptric cistulaCatoptric theatre.jpgA catoptric cistula is a box with insides made of mirrors so as to distort images of objects put into the box.
Checker shadow illusionGrey square optical illusion.svg
Grey square optical illusion proof2.svg
The checker shadow illusion shows that when a shadow is cast onto a checked board, the colours of squares A and B in the photos appear to be different, when in fact they are the same.
Chubb illusionChubbillusion.gifThe Chubb illusion is an optical illusion or error in visual perception in which the apparent contrast of an object varies substantially to most viewers depending on its relative contrast to the field on which it is displayed.
Color constancyHot air balloon - color constancy.jpgColour constancy is an example of subjective constancy and a feature of the human color perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions. A green apple for instance looks green to us at midday, when the main illumination is white sunlight, and also at sunset, when the main illumination is red.
Color phi phenomenonThe color phi phenomenon is a perceptual illusion in which a disembodied perception of motion is produced by a succession of still images.
Contingent perceptual aftereffect
Convergence micropsia
Cornsweet illusionCornsweet illusion.svgAn illusion where two colours can obviously be seen to be different when placed directly beside each other; however, when the two colours are separated by a thick black line, they appear to be of the same hue.
Delboeuf illusionDelboeuf.jpgAn optical illusion of relative size perception. The two black circles are exactly the same size; however, the one on the left seems larger.
Disappearing ModelA trompe-l'œil body painting by Joanne Gair.
Ebbinghaus illusionMond-vergleich.svgThe Ebbinghaus illusion, or Titchener circles, is an optical illusion of relative size perception. The two orange circles are exactly the same size; however, the one on the right appears larger.
Ehrenstein illusionEhrenstein.svg
The Ehrenstein illusion is an optical illusion studied by the German psychologist Walter Ehrenstein in which the sides of a square placed inside a pattern of concentric circles take an apparent curved shape.
Fechner color
Figure-ground (perception)Cup or faces paradox.svg
Filling-inTroxler fading.svg
Flash lag illusion
Forced perspectiveApplication used in film and architecture to create the illusion of larger, more distant objects.
Fraser spiral illusionFraser spiral.svgThe Fraser spiral illusion, or false spiral, or the twisted cord illusion, was first described by the British psychologist Sir James Fraser in 1908. The overlapping black arc segments appear to form a spiral; however, the arcs are a series of concentric circles.
Gravity hill
Grid illusionHermannGrid.gif
Grid illusion.svg
Any kind of grid that deceives a person's vision. The two most common types of grid illusions are the Hermann grid illusion (1870) and the scintillating grid illusion (1994). The first is characterized by "ghostlike" grey blobs perceived at the intersections of a white (or light-colored) grid on a black background. The grey blobs disappear when looking directly at an intersection. The second is constructed by superimposing white discs on the intersections of orthogonal gray bars on a black background. Dark dots seem to appear and disappear rapidly at random intersections, hence the label "scintillating". When a person keeps his or her eyes directly on a single intersection, the dark dot does not appear. The dark dots disappear if one is too close to or too far from the image.
Hering illusionHering illusion.svgThe Hering illusion (1861): When two straight and parallel lines are presented in front of radial background (like the spokes of a bicycle), the lines appear as if they were bowed outwards.
Hollow-Face illusionBjorn Borg Hollow Face.jpgThe Hollow-Face illusion is an optical illusion in which the perception of a concave mask of a face appears as a normal convex face.
Hybrid imageHybrid image decomposition.jpgA Hybrid image is an optical illusion developed at MIT in which an image can be interpreted in one of two different ways depending on viewing distance.
Illusory contoursKanizsa triangle.svgIllusory contours or subjective contours are a form of visual illusion where contours are perceived without a luminance or color change across the contour.
Illusory motion
Impossible objectImpossible cube illusion angle.svg
Irradiation illusion
Isometric illusionCubes at Heureka, optical illusion.jpgAn isometric illusion (also called an ambiguous figure or inside/outside illusion) is a type of optical illusion, specifically one due to multistable perception.
Jastrow illusionJastrow illusion.svgThe Jastrow illusion is an optical illusion discovered by the American psychologist Joseph Jastrow in 1889.
Kanizsa triangleKanizsa triangle.svgThe Kanizsa triangle is an optical illusion first described by the Italian psychologist Gaetano Kanizsa in 1955. It is a triangle formed of illusory contours.
Kinetic Depth EffectThe Kinetic depth effect refers to the phenomenon whereby the three-dimensional structural form of an silhouette can be perceived when the object is moving. In the absence of other visual depth cues, this might be the only perception mechanism available to infer the object's shape. Additionally the direction of motion can reverse due to the existence of multiple 3D visual solutions.
Leaning tower illusionThe Leaning tower illusion is an optical illusion that presents two identical images of the Leaning Tower of Pisa side by side.
Lilac chaserLilac-Chaser.gifLilac chaser is a visual illusion, also known as the Pac-Man illusion.
Liquid crystal shutter glasses
Mach bandsMach band.svgMach bands is an optical illusion named after the physicist Ernst Mach.
McCollough effectGrid for McCollough effect.svgThe McCollough effect (1965) is a phenomenon of human visual perception in which colorless gratings appear colored contingent on the orientation of the gratings. It is an aftereffect requiring a period of induction to produce it.
Missing square puzzleMissing square puzzle.svg
Missing square edit.gif
The missing square puzzle is an optical illusion used in mathematics classes to help students reason about geometrical figures.
Moon illusionMoon size illusion.pngThe Moon illusion is an optical illusion in which the Moon appears larger near the horizon than it does while higher up in the sky.
Motion aftereffect
Motion illusionAnomalous motion illusion1.svg
Müller-Lyer illusionMüller-Lyer illusion.svgThe Müller-Lyer illusion is an optical illusion consisting of a stylized arrow.
Musion Eyeliner
Necker cubeNecker cube.svgThe Necker cube is an optical illusion first published in 1832 by Swiss crystallographer Louis Albert Necker.
Numerosity adaptation effectNumerosityadaptation.png
Orbison illusionOrbison illusion.svgThe Orbison illusion is an optical illusion that was first described by the psychologist William Orbison in 1939.
Penrose stairsImpossible staircase.svgThe Penrose stairs was created by Lionel Penrose and his son Roger Penrose.[1] A variation on the Penrose triangle, it is a two-dimensional depiction of a staircase in which the stairs make four 90-degree turns as they ascend or descend yet form a continuous loop, so that a person could climb them forever and never get any higher.
Penrose trianglePenrose triangle.svgThe Penrose triangle was first created by the Swedish artist Oscar Reutersvärd in 1934. The mathematician Roger Penrose independently devised and popularised it in the 1950s, describing it as "impossibility in its purest form".
Pepper's ghost
Perceived visual angleVisualAngleAboveHorizonDefs.svg
Peripheral drift illusionPDIFaubertHerbert.pngA motion illusion (1979/1999) generated by the presentation of a sawtooth luminance grating in the visual periphery.
PhantogramPhantogram projection diagram.svgPhantograms, also known as Phantaglyphs, Op-Ups, free-standing anaglyphs, levitated images, and book anaglyphs, are a form of optical illusion.
Phi phenomenon
Poggendorff illusionPoggendorff illusion.svgThe Poggendorff illusion (1860) involves the misperception of the position of one segment of a transverse line that has been interrupted by the contour of an intervening structure (here a rectangle).
Ponzo illusionPonzo illusion.gifIn the Ponzo illusion (1911) two identical lines across a pair of converging lines, similar to railway tracks, are drawn. The upper line looks longer because we interpret the converging sides according to linear perspective as parallel lines receding into the distance. In this context, we interpret the upper line as though it were farther away, so we see it as longer – a farther object would have to be longer than a nearer one for both to produce retinal images of the same size.
Rubin vaseRubin2.jpgRubin vase (1915): an ambiguous or bi-stable (i.e., reversing) two-dimensional form.
Sander illusionSander Illusion.svgIn Sander's parallelogram (1926) the diagonal line bisecting the larger, left-hand parallelogram appears to be considerably longer than the diagonal line bisecting the smaller, right-hand parallelogram, but is in fact the same length.
SilencingSilencinghue.jpgSilencing is an illusion in which a set of objects that change in luminance, hue, size, or shape appears to stop changing when it moves.
Size–weight illusionThe size–weight illusion is also known as the Charpentier illusion (or Charpentier–Koseleff illusion).
Stroboscopic effectStrobe 2.gif
Swept-plane display
Ternus illusionThe Ternus illusion (1926/1938) is based upon apparent motion.
ThaumatropeTaumatropio fiori e vaso, 1825.gifA thaumatrope is a toy that was popular in Victorian times.
Troxler's fadingTroxler's fading: When one fixates on a particular point for even a short period of time, an unchanging stimulus away from the fixation point will fade away and disappear.
Vertical–horizontal illusionVertical–horizontal illusion.pngThe Vertical-horizontal illusion is the tendency for observers to overestimate the length of a vertical line relative to a horizontal line of the same length.
Visual tilt effectsTiltIllusion.jpg
Wagon-wheel effectWagonWheelEffect.gif
White's illusionWhite illusion.svg
Wundt illusionWundt illusion.svgThe two red vertical lines are both straight, but they may look as if they are bowed inwards to some observers. The distortion is induced by the crooked lines on the background
Zöllner illusionZollner illusion.svgThe Zöllner illusion is a classic optical illusion named after its discoverer, German astrophysicist Johann Karl Friedrich Zöllner.

See also[edit]


  1. Jump up ^ Penrose, LS; Penrose, R. (1958). "Impossible objects: A special type of optical illusion". British Journal of Psychology 49 (1): 31–33. doi:10.1111/j.2044-8295.1958.tb00634.x. PMID 13536303. 

External links[edit]


  1. Hi Searle88

    Great blog - we share many interests -

    I like the illusions post - my favourite is the concave/convex face!

    Are you able to point me to the source of the background on your blogger site - my wife is a painter and will be very interested. It is strong without being distracting.



  2. Unfortunately, I am unable to point to the background source(s) of the "concave/convex face." A simple google word search should do the trick..and thank you for your compliment about the Blog. It is appreciated.