Visual perception-illusions-paradoxes

Visual PerceptionVisual PerceptionIllusions &Illusions &

ddParadoxesParadoxesPriyadarshi PatnaikPriyadarshi PatnaikAssociate ProfessorAssociate Professor

D f H i i & S i l S iD f H i i & S i l S iDepartment of Humanities & Social SciencesDepartment of Humanities & Social SciencesIIT KharagpurIIT Kharagpur

What about visuals?What about visuals?What about visuals?What about visuals?

Many things which are visually communicated orMany things which are visually communicated orMany things which are visually communicated or Many things which are visually communicated or perceived are biologically determinedperceived are biologically determinedBut many other things are learntBut many other things are learntBut many other things are learntBut many other things are learntVisuals communicate powerVisuals communicate powerVisuals communicate emotionsVisuals communicate emotionsVisuals communicate cultureVisuals communicate culture

The PanopticonThe PanopticonThe PanopticonThe Panopticon

Jeremy Bentham (1785)Jeremy Bentham (1785)Discipline and PunishDiscipline and Punish

ParanoiaParanoiaParanoiaParanoiaControlControlFearFear

Close circuitClose circuitEPREPR

Visuals and the Communication of Emotions

What is perception?What is perception?What is perception?What is perception?

SensationSensation

++

InterpretationInterpretationInterpretationInterpretation

In philosophy psychology and the cognitiveIn philosophy psychology and the cognitiveIn philosophy, psychology, and the cognitive In philosophy, psychology, and the cognitive sciences, sciences, perceptionperception is the process of attaining is the process of attaining awareness or understanding of sensoryawareness or understanding of sensoryawareness or understanding of sensory awareness or understanding of sensory information. The word "perception" comes information. The word "perception" comes from the Latin wordsfrom the Latin words perceptio percipioperceptio percipio and meansand meansfrom the Latin words from the Latin words perceptio, percipio,perceptio, percipio, and means and means "receiving, collecting, action of taking "receiving, collecting, action of taking possession apprehension with the mind orpossession apprehension with the mind orpossession, apprehension with the mind or possession, apprehension with the mind or senses."senses."

When external stimuli is transmitted to our brainWhen external stimuli is transmitted to our brainWhen external stimuli is transmitted to our brain When external stimuli is transmitted to our brain through our senses through our senses –– sensation sensation Devoid of any definition, any interpretation,Devoid of any definition, any interpretation,Devoid of any definition, any interpretation, Devoid of any definition, any interpretation, meaningmeaningThe simplest building blockThe simplest building blockThe simplest building blockThe simplest building blockBut then it is taken up by the mind and analyzedBut then it is taken up by the mind and analyzedMemory is stirred up remembering usedMemory is stirred up remembering usedMemory is stirred up, remembering usedMemory is stirred up, remembering usedSensation identified, matched, given a name, Sensation identified, matched, given a name, defined interpreted and remembered for futuredefined interpreted and remembered for futuredefined, interpreted and remembered for future defined, interpreted and remembered for future useuse

Part of what we perceive comes through thePart of what we perceive comes through thePart of what we perceive comes through the Part of what we perceive comes through the senses from the objects before us; another part senses from the objects before us; another part always comes out of our own headalways comes out of our own headalways comes out of our own headalways comes out of our own head

Willi JWilli JWilliam JamesWilliam James

Subjective perceptionSubjective perceptionSubjective perceptionSubjective perception

Image credit: Mark R. Homes @ National Geographic Society

To resolve ambiguities and make sense of theTo resolve ambiguities and make sense of theTo resolve ambiguities and make sense of the To resolve ambiguities and make sense of the world, the brain also creates shapes from world, the brain also creates shapes from incomplete dataincomplete dataincomplete data.incomplete data.

Th i l d l d b I liTh i l d l d b I liThe triangle you saw was developed by Italian The triangle you saw was developed by Italian psychologist Gaetano Kanizsa. psychologist Gaetano Kanizsa.

IllusionIllusionIllusionIllusion

Image credit: Mark R. Homes @ National Geographic Society

Illusion created because of “size constancy”Illusion created because of “size constancy”Illusion created because of size constancy Illusion created because of size constancy effect to be discussed a little later.effect to be discussed a little later.

OrientationOrientationOrientationOrientation

Image credit: Mark R. Homes @ National Geographic Society

According to noted neuroscientist VAccording to noted neuroscientist VAccording to noted neuroscientist V. According to noted neuroscientist V. Ramachandran of University of California, San Ramachandran of University of California, San Diego the brain can make guesses based onDiego the brain can make guesses based onDiego, the brain can make guesses based on Diego, the brain can make guesses based on information available and some simple information available and some simple assumptionsassumptionsassumptionsassumptionsPattern of shadowsPattern of shadowsLi h ll fLi h ll fLight usually from top Light usually from top

Which are the concaves now?Which are the concaves now?Which are the concaves now?Which are the concaves now?

OrientationOrientationOrientationOrientation

From the eye to the mindFrom the eye to the mindFrom the eye to the mindFrom the eye to the mind

Retina

brain

1 2

eye

1 R l t ti LGN1: Relay station - LGN

2: Primary and more advanced area of visual cortex

Rods: Monochrome and in low lightRods: Monochrome and in low lightRods: Monochrome and in low lightRods: Monochrome and in low lightCones: colour vision Cones: colour vision

AttentionAttentionAttentionAttention

The perceptual process of selecting certainThe perceptual process of selecting certainThe perceptual process of selecting certain The perceptual process of selecting certain inputs for inclusion in our conscious experience inputs for inclusion in our conscious experience or awareness at any given timeor awareness at any given timeor awareness at any given timeor awareness at any given time

Flash animation

Image taken Flash Animation Software demo movie

FilteringFilteringFilteringFiltering

Why does focus shift?Why does focus shift?Why does focus shift?Why does focus shift?

W fil l bl ki i iW fil l bl ki i iWe filter, partly blocking certain inputsWe filter, partly blocking certain inputs

Limited Mental CapacityLimited Mental Capacity

Perception is taking in, filtering and interpretation toPerception is taking in, filtering and interpretation toPerception is taking in, filtering and interpretation to Perception is taking in, filtering and interpretation to make sense of the world. Memory and learning play an make sense of the world. Memory and learning play an important part, but so do certain innate organizational important part, but so do certain innate organizational abilities of the mind, highlighted by Gestalt abilities of the mind, highlighted by Gestalt psychologists.psychologists.

The limits of my perception are the limits of my worldThe limits of my perception are the limits of my worldThe word is the world (since it takes us a step further The word is the world (since it takes us a step further and helps us cognize what we have perceived) and helps us cognize what we have perceived)

What we shall do nextWhat we shall do nextWhat we shall do nextWhat we shall do next

Form perceptionForm perceptionForm perceptionForm perceptionColour perceptionColour perceptionD h iD h iDepth perceptionDepth perception

These will give us some idea of how and why we These will give us some idea of how and why we visually perceive the many things that we do.visually perceive the many things that we do.y p y gy p y g

Form Perception and Form Perception and G lG lGestaltGestalt

Gestalt (German) used to indicate the formGestalt (German) used to indicate the form--Gestalt (German) used to indicate the formGestalt (German) used to indicate the formforming capabilities of the mind (Whole form forming capabilities of the mind (Whole form approach) and the belief that this holisticapproach) and the belief that this holisticapproach) and the belief that this holistic approach) and the belief that this holistic perception is innate to the mindperception is innate to the mind

FigureFigure--groundgroundgu egu e g ou dg ou d

M.C. Escher: Moebious with Birds

The visual system uses an innate binary divisionThe visual system uses an innate binary divisionThe visual system uses an innate binary division The visual system uses an innate binary division –– the figure we look at and the ground which is the figure we look at and the ground which is everything else and forms the backgroundeverything else and forms the backgroundeverything else and forms the backgroundeverything else and forms the backgroundThis relation is reversibleThis relation is reversibleB i h hi fiB i h hi fiBut we cannot perceive the same thing as figure But we cannot perceive the same thing as figure and ground at the same time and ground at the same time –– it requires a it requires a

l i hil i himental switchingmental switching

GestaltGestaltGestaltGestalt

Max WertheimerMax WertheimerMax WertheimerMax WertheimerKurt KoffkaKurt KoffkaW lf K hlW lf K hlWolfgang KohlerWolfgang Kohler

We are surrounded by sounds and forms that do We are surrounded by sounds and forms that do not have a sole meaning. At any moment, our not have a sole meaning. At any moment, our g y ,g y ,perception is what gives it form and meaning.perception is what gives it form and meaning.

What do we have here?What do we have here?What do we have here?What do we have here?

Twelve lines4 vertical4 horizontal4 oblong

The vase and the two facesThe vase and the two facesThe vase and the two facesThe vase and the two faces

A demonstration of multi-stability: popping back and forth between two or more unstable perceptions

Organization in form perceptionOrganization in form perceptionOrganization in form perceptionOrganization in form perception

The whole is more h h f ithan the sum of its

parts

A PoemA Poem

A Black CoatIt d k iIt was a dark evening

Simple Life

Subjective Contour/ReificationSubjective Contour/ReificationSubjective Contour/ReificationSubjective Contour/Reification

Image credit: Mark R. Homes @ National Geographic Society

ProximityProximityProximityProximity

SimilaritySimilaritySimilaritySimilarity

The law of good figureThe law of good figureThe law of good figureThe law of good figure

ContinuityContinuityContinuityContinuity

ClosureClosureClosureClosure

EmergenceEmergenceEmergenceEmergence

Shape constancy or invarianceShape constancy or invarianceShape constancy or invarianceShape constancy or invariance

AnalysisAnalysisAnalysisAnalysis

Analyze these Dali imagesAnalyze these Dali imagesAnalyze these Dali imagesAnalyze these Dali images

Salvador Dali: Mae West

Salvador Dali: Narcissus

Salvador Dali: The Phantom Cart

Salvador Dali: Galatea of Spheres

Depth PerceptionDepth PerceptionDepth PerceptionDepth Perception

D th P tiDepth Perception

MonocularMonocular

Binocular

BinocularBinocular

Photograph: Priyadarhsi Patnaik

Linear perspectiveLinear perspectiveLinear perspectiveLinear perspective

V i hi i tVanishing pointHorizon

Road

Dali: Vertigo

Interposition

Relative SizeRelative SizeRelative SizeRelative Size

The farther an object is from the eye the smallerThe farther an object is from the eye the smallerThe farther an object is from the eye, the smaller The farther an object is from the eye, the smaller it looksit looksThe episode of the buffalosThe episode of the buffalosThe episode of the buffalosThe episode of the buffalos

Gustave Caillebotte: Paris

Size ConstancySize Constancy

Illusion roomIllusion roomIllusion roomIllusion room

Source: Blog site: MirageStudio7

Perceptual assumptionPerceptual assumptionPerceptual assumptionPerceptual assumption

Source: Encyclopedia Britannica Deluxe Edition 2007

Colour PerceptionColour PerceptionColour PerceptionColour Perception

Source: Encyclopedia Britannica 2007 Deluxe Edition

Colour wheelColour wheelColour wheelColour wheel

Website of “The Joy of Perception”

Simultaneous Contrast

Website of “The Joy of Perception”

Source: “Color in Mind: Adobe Magazine, November 1996

SizeSizeSize Size

Source: “Color in Mind: Adobe Magazine, November 1996

Brightness, colour and depthBrightness, colour and depthBrightness, colour and depthBrightness, colour and depth

Website of “The Joy of Perception”

The light coloured dotThe light coloured dotThe light coloured dot The light coloured dot seems to pop out while seems to pop out while the dark coloured dot the dark coloured dot seems to sit further backseems to sit further back

Source: “Color in Mind: Adobe Magazine, November 1996

AnalysisAnalysisAnalysisAnalysis

Seurat: the Bathers

De Chirico: The Nostalgia of Infinite

Munch: The Scream

Francis Bacon: Crucifixion 3

Van Gogh: Cypress in Starry Night

Van Gogh: Wheatfield under threatening skies

Tibetan Buddhist Tanka painting

Colour symbolismColour symbolismColour symbolismColour symbolism

Cultural differencesCultural differencesCultural differencesCultural differencesAge differenceAge differenceCl diffCl diffClass differenceClass differenceGender differenceGender differenceTrend or current fashionTrend or current fashion

IllusionIllusionIllusionIllusion

There is an innate ambiguity in retinal input. For a There is an innate ambiguity in retinal input. For a g y pg y pgiven retinal image, there are infinite number of three given retinal image, there are infinite number of three dimensional images available for interpretation. Usually dimensional images available for interpretation. Usually

t th i t rpr t ti ri ht Wh d ’t ht th i t rpr t ti ri ht Wh d ’t hwe get the interpretation right. When we don’t, we have we get the interpretation right. When we don’t, we have an illusion.an illusion.Some illusions arise because there are more than oneSome illusions arise because there are more than oneSome illusions arise because there are more than one Some illusions arise because there are more than one possible interpretations.possible interpretations.An An illusionillusion is a distortion of the senses, revealing how is a distortion of the senses, revealing how the brain normally organizes and interprets sensory the brain normally organizes and interprets sensory stimulation. stimulation.

Types ofTypes ofTypes ofTypes of

Ambiguous illusionsAmbiguous illusions are pictures or objects that are pictures or objects that gg p jp jelicit a perceptual 'switch' between the alternative elicit a perceptual 'switch' between the alternative interpretations. interpretations. Distorting illusionsDistorting illusions are characterized by distortionsare characterized by distortionsDistorting illusionsDistorting illusions are characterized by distortions are characterized by distortions of size, length, or curvature. of size, length, or curvature. Paradox illusionsParadox illusions are generated by objects that are are generated by objects that are

d i l i ibld i l i iblparadoxical or impossible.paradoxical or impossible.Fictional illusions (Hallucinations)Fictional illusions (Hallucinations) are defined as are defined as the perception of objects that are genuinely not there the perception of objects that are genuinely not there p p bj g yp p bj g yto all but a single observer, such as those induced by to all but a single observer, such as those induced by schizophrenia or a hallucinogen. schizophrenia or a hallucinogen.

Image source: Encyclopedia Britannica 2007 deluxe edition

Image source: Encyclopedia Britannica 2007 deluxe edition

Image source: www.scientificpsychic.com

Shape contrast: contextShape contrast: contextShape contrast: contextShape contrast: context

Image source: www.colorcube.com

Simultaneous contrast/spreadingSimultaneous contrast/spreadingSimultaneous contrast/spreadingSimultaneous contrast/spreading

Image source: www.colorcube.com

Image source: www.scientificpsychic.com

Escher: Birds & fish

Escher on EscherEscher on EscherEscher on EscherEscher on Escher

"In the horizontal center strip there are birds and fish"In the horizontal center strip there are birds and fishIn the horizontal center strip there are birds and fish In the horizontal center strip there are birds and fish equivalent to each other. We associate flying with sky, equivalent to each other. We associate flying with sky, and so for each of the black birds the sky in which it isand so for each of the black birds the sky in which it isand so for each of the black birds the sky in which it is and so for each of the black birds the sky in which it is flying is formed by the four white fish which encircle it. flying is formed by the four white fish which encircle it. Similarly swimming makes us think of water andSimilarly swimming makes us think of water andSimilarly swimming makes us think of water, and Similarly swimming makes us think of water, and therefore the four black birds that surround a fish become therefore the four black birds that surround a fish become the water in which it swims "the water in which it swims "the water in which it swims.the water in which it swims.

Escher: Bond of union

Escher: Day & night

Escher: Mobius strip II

Magritte: Call of the Peaks

Magritte: the blank cheque

Giuseppe Arcimboldo (1527 1593)(1527-1593)Italian Artist

Pieter Bruegel the Elder (1525-1559), Netherlands

Jos de Mey(1928 - 2007)

Belgian Artist

Rob Gonsalves (1959-)

Canadian Painter

Octavio Ocampo (1943-)

Mexican Artist

Shigeo Fukuda(1932-2009)

References and imagesReferences and imagesReferences and imagesReferences and images

Doors of PerceptionDoors of Perceptionhttp://www.doorsofperception.com/doorshttp://www.doorsofperception.com/doors

The Joy of PerceptionThe Joy of Perceptionhttp://www.yorku.ca/eyehttp://www.yorku.ca/eyehttp://www.yorku.ca/eyehttp://www.yorku.ca/eye

Perception OnlinePerception Onlinehttp://www.pion.co.uk/perceptionhttp://www.pion.co.uk/perception

“P ti ”“P ti ” E l p di B it i 2007 D l EditiE l p di B it i 2007 D l Editi“Perception.” “Perception.” Encyclopedia Britannica 2007 Deluxe Edition.Encyclopedia Britannica 2007 Deluxe Edition.Art and Visual Perception. Art and Visual Perception. Rudolf Arnheim, University of Rudolf Arnheim, University of California Press, 1984.California Press, 1984.M k H di ’ A hi (M k H di ’ A hi ( hihi ))Mark Hardin’s Artchive (Mark Hardin’s Artchive (www.artchive.comwww.artchive.com) ) Colour. Bettey Edwards, Colour. Bettey Edwards, Tarcher/Penguin, 2004.Tarcher/Penguin, 2004.Perception, Gestalt, Panopticon, etc (Wikipedia)Perception, Gestalt, Panopticon, etc (Wikipedia)p p ( p )p p ( p )