optical illusions
DESCRIPTION
Optical Illusions. Seeing Is Deceiving. Christopher Landauer Science of Art March 9, 2000. What is an Illusion?. il·lu·sion ( î -l ¡¹ zh e n ) noun 1. a. An erroneous perception of reality. b. An erroneous concept or belief. - PowerPoint PPT PresentationTRANSCRIPT
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OpticalOptical IllusionsIllusions
Seeing Is Seeing Is
DeceivingDeceiving
Christopher LandauerScience of ArtMarch 9, 2000
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What is an Illusion?What is an Illusion?
il·lu·sion (-lzhn) noun1. a. An erroneous perception of reality. b. An erroneous concept or belief.2. The condition of being deceived by a false perception or belief.3. Something, such as a fantastic plan or desire, that causes an
erroneous belief or perception.4. Illusionism in art.
• Latin root of illusion is illudere which means “to mock”• Optical illusions mock our trust in our senses• Suggest that the eye is not a passive camera; rather, perception is an active process that takes place in the brain and is not directly predictable from simple knowledge of physical relationships
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What’s the big deal?What’s the big deal?
• Human reliance on correspondence between conscious experience and physical reality
• Continual verification of our senses
• Cultural Heritage– “Seeing is Believing”– “See it with my own two
eyes”
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History of IllusionsHistory of Illusions
Prehistory:
• Afterimage caused by glancing at the sun
• A stick half in and half out of water
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History of IllusionsHistory of Illusions
500 B.C. - Height of the Greek Period
“The eyes and ears are bad witnesses when they are at the service of minds that do not understand their language”
-Parmenides
Two Viewpoints on Perception:
1. Sensory inputs are inaccurate. Mind corrects these inaccuracies to
provide an accurate representation of the environment.
Illusions: Senses are relied on more than the Mind
2. Senses are inherently accurate and produce a true picture of the
environment. Mind is limited.
Illusions: Mind interferes with the Senses
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History of IllusionsHistory of Illusions
c. 450 B.C.“The mind sees and the mind hears. The rest is blind and deaf.”
-Epicharmus
“Man is nothing but a bundle of sensations”-Protagoras
c. 300 B.C. “We must perceive objects through the senses but with the mind”
-Plato
384 - 322 B.C. “Each sense has one kind of object which it discerns, and never errs in reporting that what is before it is color or sound; Although, it may err as to what it is that is colored or where it is, or what it is that is sounding, or where it is.”
-Aristotle
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History of IllusionsHistory of Illusions
A. Ideal Parthenon
B. Architrave Illusion(Jastrow-Lipps)
C. Illusionary Distortion
D. Alterations made to offset illusion
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History of IllusionsHistory of Illusions
“For the sight follows gracious contours; and unless we flatter its pleasure by proportionate alterations of the modules--so that by adjustment there is added the amount to which suffers illusion--an uncouth and ungracious aspect will be presented to the spectators.”
-Vitruvius
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History of IllusionsHistory of Illusions
Entasis:Convexing of column to overcome parallel lines appearing concave
Irradiation Illusion:Bright objects appear larger
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History of IllusionsHistory of Illusions
Conclusion:
“More of an Art than a Science”
Early Preparadaigmatic Science-Trial and error-Aesthetic, not scientific-No factual understanding-No treatsies-No schools of thought
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History of IllusionsHistory of Illusions
1596 - 1650 Descartes:There is both a registration stage and an interpretation stage
in the perceptual process. Perceptual error or illusion may intrude at either of these two steps along the road to consciousness.
1700 - 1800 Given at Birth vs. Learned through Experience
Reid & Kant: All knowledge of the external world comes directly through the senses and is interpreted by innate mechanisms
Berkeley & Hume: All perceptual qualities are learned through experience with the environment
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History of IllusionsHistory of Illusions
1800 - 1870 Experimental Foundations
Mueller, E.H. Weber, Helmholtz, Baldwin, Hering use Physics, Physiology, Philosophy to form treatises
Specialist and Non-specialist working in area of visual geometric illusions carrys on to the present
1922 - Luckiesh: lighting engineer1964 - Tolansky: physicist1972 - Robinson: psychologist
1900s Revolution and Rebirth• Behaviorists vs. Gestalt • Methodology vs. Theoretical• Percepual response & Brain wave patterns
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Current State of Current State of Illisions Illisions
Conclusion:Paradigmatic Science (Psychology)
1900s Normal Sciences => Anomoly => Crisis => Revolution
Current status: Normal Science- mopping up- puzzle solving- guidelines for research
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Ambiguous FiguresAmbiguous Figures
Face or Vase?Face or Vase?
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Ambiguous FiguresAmbiguous Figures
L'Amour de PierrotL'Amour de Pierrot c.1905c.1905
Gossip and SatanGossip and Satan
Geo. A. WotherspoonGeo. A. Wotherspoon
RetroActiveRetroActive
Nels IsralsonNels Isralson
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Ambiguous FiguresAmbiguous Figures
Slave Market With the Disappearing Bust of Voltaire - Salvadore Dali, 1940
Bust of VoltaireBust of Voltaire- Houdon, 1781- Houdon, 1781
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Ambiguous FiguresAmbiguous Figures
The Great Panoramic - Salvadore Dali, 1936
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Ambiguous FiguresAmbiguous Figures
22
2 2
22
33
Multiple FiguresMultiple Figures
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Ambiguous FiguresAmbiguous Figures
Mask ConcavityMask Concavity
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Ambiguous FiguresAmbiguous Figures
Mach’s FigureMach’s Figure
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Ambiguous FiguresAmbiguous Figures
Schroder’s StaircaseSchroder’s Staircase
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Ambiguous FiguresAmbiguous FiguresOscillating CubesOscillating Cubes
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Ambiguous FiguresAmbiguous Figures
Necker CubeNecker Cube
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Ambiguous FiguresAmbiguous Figures
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Ambiguous FiguresAmbiguous Figures
Cube looks like a cube.
“Equal sides and right angles.”
Eye: Perspetive projection
Reverse: Topless pyramid change of shape
Cube looks distorted, on face smaller than the other.
Depth is paradoxical
Reverse: No Change
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Ambiguous FiguresAmbiguous Figures
Cube does not look like a cube.
Eye: Near face is same size as far face
Reverse: Topless pyramid further face always looks larger
Necker Cube. No face is front or back by perspective
Depth is paradoxical
Reverse: No change
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Ambiguous FiguresAmbiguous Figures
Possible views:
• Cube with corner missing
• Box in corner of room
• Small cube infront of large cube
3 in 1 Illusion3 in 1 Illusion
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Ambiguous FiguresAmbiguous FiguresCube / RoomCube / Room
Possible views:
• 3D Cube
• Corner of Room