Optical Illusions
description
Transcript of Optical Illusions
OpticalOptical IllusionsIllusions
Seeing Is Seeing Is
DeceivingDeceiving
Christopher LandauerScience of ArtMarch 9, 2000
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
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”
History of IllusionsHistory of Illusions
Prehistory:
• Afterimage caused by glancing at the sun
• A stick half in and half out of water
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
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
History of IllusionsHistory of Illusions
A. Ideal Parthenon
B. Architrave Illusion(Jastrow-Lipps)
C. Illusionary Distortion
D. Alterations made to offset illusion
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
History of IllusionsHistory of Illusions
Entasis:Convexing of column to overcome parallel lines appearing concave
Irradiation Illusion:Bright objects appear larger
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
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
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
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
Ambiguous FiguresAmbiguous Figures
Face or Vase?Face or Vase?
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
Ambiguous FiguresAmbiguous Figures
Slave Market With the Disappearing Bust of Voltaire - Salvadore Dali, 1940
Bust of VoltaireBust of Voltaire- Houdon, 1781- Houdon, 1781
Ambiguous FiguresAmbiguous Figures
The Great Panoramic - Salvadore Dali, 1936
Ambiguous FiguresAmbiguous Figures
22
2 2
22
33
Multiple FiguresMultiple Figures
Ambiguous FiguresAmbiguous Figures
Mask ConcavityMask Concavity
Ambiguous FiguresAmbiguous Figures
Mach’s FigureMach’s Figure
Ambiguous FiguresAmbiguous Figures
Schroder’s StaircaseSchroder’s Staircase
Ambiguous FiguresAmbiguous FiguresOscillating CubesOscillating Cubes
Ambiguous FiguresAmbiguous Figures
Necker CubeNecker Cube
Ambiguous FiguresAmbiguous Figures
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
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
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
Ambiguous FiguresAmbiguous FiguresCube / RoomCube / Room
Possible views:
• 3D Cube
• Corner of Room