Psychology of Perception
Instructor:
William M. Mace
Email: william.mace@trincoll.edu
Required Reading
All reading will be available online.
Webvision textbook. This has far more detail about the eye and vision than we will use. It is an excellent resource and some readings will be selected from it.
Schedule of Classes |
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| Date | Reading for Class | Topic description | ||
What the topic, “Perception,” is about |
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| Class 1January 21 | Causality: What causes what? And here? A little to big effect.Light from the stars — things to think about. “Our galaxy has a diameter somewhere around 100,000 light years.” One light year is around 6 trillion miles. [a trillion is 1,000,000,000,000]. See also: How far is that?
Framework for thinking about perception The Electromagnetic spectrum (Broken link) All of these kinds of radiation are different and have widely different uses, but they also are the SAME. In what way? They are the SAME as electromagnetic radiation. They are DIFFERENT in wavelength and frequency. Click HERE to learn about the wavelength and frequency property of all waves. Note that SOUND waves are NOT electromagnetic waves and are not on the list of types of electromagnetic radiation. Sound is based on the actual mechanical vibration of molecules in the air that eventually move your tympanic membrane (ear drum) back and forth. That means that sound cannot travel in a vacuum, where there are no molecules. Light travels through outer space, sound does not. Richard Feynman reflecting on vision and the electromagnetic spectrum HERE See assignment at beginning of the next syllabus entry! |
Perception is how we find out about the world through seeing, hearing, touching, tasting, and smelling. Without perceiving, we have nothing to remember and nothing to talk about. Without perceiving, we could not be in touch with our world — and could not exist. To know what is in the world, and where you are in it, at every moment, depends on perceiving. Are you hungry? That is perceiving. Where is something to eat? How do you get it? How do you know that you are eating? All of those things involve perceiving. The topic is a great challenge to science because so much of what we know we have to figure out does not necessarily answer our fundamental questions about how perceiving can work.Perception, as a topic, is totally interdisciplinary. I have colleagues engaged in trying to understand perception in the following areas (in no particular order) –philosophy, biology, neuroscience, physics, chemistry, engineering, robotics, arts, painting, sculpture, architecture, film. Mathematics, physical therapy, kinesiology, computer vision, computer animation, video games. Within psychology, social, developmental, memory, human factors, design. We won’t cover all of those, but if you have special interests in any of those, please let me know.Bookkeeping in the course Even though our major source of light is from the sun (a star among how many stars?), we do not “see stars” most of the time. We see the earth and what populates it. Do we have principles for seeing the substantial earth, as opposed to light alone? |
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| Class 2January 23 | Do the reading and watch the videos before class TODAY: Watch the 2 videos below then 1. answer the question: Do you see the world as it really is? 2. write out 3 [three total] relevant quotes from the videos. Tell me where each quote came from as precisely as you can. Send your work to me on Moodle by 10 pm Sunday night (Jan. 25).How to find the Video — go to “Films on Demand” in the Trinity Online Resources section of the Library website and, under “Psychology > Biological Psychology > Sensation and Perception,” find the video, “Is Seeing Believing? New Frontiers in the Science of the Senses.”
Video: Is Seeing Believing? [Mainly sections 1, 2, and 7 — out of 23] Framework for thinking about perception READ: Richard Gregory’s statement of the fundmental problem. |
Ambiguity. When a shape, for example, is ambiguous, that means that it has more than one interpretation. The sensitive part of the back of the eyeball is called the retina. You’ll hear a lot about it. The first important fact about the retina is that it is flat. The 3D layout of the world is projected onto this flat surface. This results in supposedly infinite ambiguity. That’s one theory anyway. The persistent puzzle is that our everyday world is not as ambiguous as some scientists think. Why? [This is a big question and won’t get an easy answer] | ||
| Class 3January 26 |
Notes elaborating first two classesContinue readings from last timeHigh School Video reply — Seattle suburbs Purves figure that you can manipulate Richard Gregory’s statement of the fundmental problem. Course Framework — linked again. Same as Jan. 21 and 23 item. The Gibsons developed what is called The Ecological Approach. Their reply to Gregory is a short précis backed by many years’ work.Gibson’s reply to Gregory HOMEWORK: TURN IN BY TUESDAY NIGHT (Jan. 27) AT 10 PM — |
The Causal Theory of Perception — or “Where did the light go?” For that matter: “Where did the environment go?” | ||
Lights! |
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| Class 4January 28 |
Tufte signs — This is to make the point about the 2 different meanings of the word “size.” Just as the Purves (Lotto) figure makes the same point about two meanings of “color.” Ask questions if you don’t follow this in class. Newton’s Opticks. (4th edition, 1730). Page numbers are in square brackets on the right. For one of the most famous quotes, see p. 125, the paragraph labeled “Definition.” Here is the main quote highlighted in the famous paragraph from the above. |
Light, color, the eye and SENSATION; Johannes Müller’s Specific Nerve Energies. “The rays are not colored.” What??! | ||
| Class 5January 30 |
Newton’s Opticks. (4th edition, 1730). Page numbers are in square brackets on the right. For one of the most famous quotes, see p. 125, the paragraph labeled “Definition.” Here is the main quote highlighted in the famous paragraph from the above. 2. BU website on ADDITIVE color “mixing.” 3. Newton Demonstration Open a PowerPoint file to see another place where you can experiment with additive mixing. |
Wavelength is physics; color is psychology (experience)In color, what is GIVEN? What is GOT? | ||
| Class 6February 2 |
SNOW DAY Explore what you can do with mixing colors on PowerPoint. |
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| Class 7February 4 | Number 4 from Jan. 30 — Light and Color IntroductionColor section of the Web book. Read the Introduction very carefully. It is a priceless statement.
I have not yet assigned to you this entire article (only the 3 Introductory paragraphs). BUT, if you will scroll through this entire color article, you will see that there are no references to surfaces that reflect light in the entire article. What does the author imply is GIVEN? What is GOT? Notice also what is in Figures 1A and Figure 15. Two kinds of color “mixing” illustrated again — From Michael Bach website Pay attention first only to the left side where “additive” mixing is demonstrated. This is a repeat of display 5 above. This is the MOST useful interactive demonstration because it allows you to manipulate and study the results of both additive and subtractive “mixing” in the same display. PLAY WITH it a lot and study what happens. Studying what happens with many different conditions on this display is one of the best uses of your study time. You should also know the material in the pages linked to #4 above as well. Powerpoint color based mixing assignment Due Friday, Feb. 6. Note that you will submit ONE SLIDE of a PowerPoint file and that the name of your file should begin with your last name. Submit your PowerPoint on Moodle. |
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| Class 8February 6 | Learning about SUBTRACTION of wavelengths through filters.Study the right hand side of the interactive color display by Michael Bach Michael Bach website
Color Samples to show effect of filters in class |
What happens if we additively mix 3 very narrow band wavelengths? Say 440 nm, 575 nm and 620 nm.What is a metamer?
rgb Homework due today
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| Class 9February 9 | One example website with rgb colors and namesOur color name results | |||
| Class 10 February 11 |
OrangesColor swatches for orange set
Lighting from GE. Try looking at the spectra. Look at sodium vapor last. READ: Main Heading, “Learn about Light.” Then links to each of the subsections under the “Learn about Light” heading. For our Perception class, pay special attention to the subsections about seeing light, including “Matching” and “Adaptation.” Interesting wording to examine. Spider vision article. Edmunds filter data — Excel spreadsheet |
Detailed review: The spectrum as numbers vs. The spectrum as color experience. How the difference implies METAMERS. |
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| Class 11 February 13 |
Review of last classes.What you should know now | |||
| Class 12 February 16 |
REVIEW | |||
| Class 13 February 18 |
Exam I | |||
| Class 14 February 20 |
Single wavelength, single visual pigment matchingFull presentation of cone pigment logic (THIS LINK LEADS TO AN ONLINE POWERPOINT???). If you cannot read this file, you can get the original PowerPoint here.
See also Figure 14 in the section linked next. Read about Photoreceptors [only] Facts and figures about human retina. From the end of the online vision book. |
Wavelength (physical) and color (psychological)What happens if we additively mix 3 very narrow band wavelengths? Say 440 nm, 575 nm and 620 nm.
What is a metamer? Beginning discussion of details of relation between number of underlying pigments in the retina and number of wavelengths that can be discriminated. Finishing details about how 3 pigments work with respect to matching experiments Keep track of where these numbers are. You don’t have to remember the numbers, but I do want you to know where you can find them. |
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| Class 15 February 23 |
Today’s topic in class is detailed look at consequences of the absorption curve for rhodopsin.Full presentation of cone pigment logic Expanded version. | |||
| Class 16 February 25 |
Full presentation of cone pigment logic.Expanded version.Three cone pigment absorption curves
See also Figure 14 in the section linked next. Read about Photoreceptors [only] Facts and figures about human retina. From the end of the online vision book. |
Full cone pigment logic and matching experiments | ||
More about colors of the Rainbow. What we know based on COLOR APPEARANCE. |
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| Class 17 March 2[Friday was a Trinity Day] |
Updated PowerPoint on “The Dress”.Opponent Color Powerpoint
Opponent processes (ONLINE POWERPOINT) Read: Hurvich, L. & Jameson, D. (1974). Opponent Processes as a model for neural organization. American Psychologist, 29(2) 88 – 102. |
Color II. Goethe, Hering, and Hurvich & Jameson.Finishing Opponent Processes. Explaining the Hurvich and Jameson measurements of opponent colorsOpponent processes: How is color EXPERIENCE organized?Full presentation of Opponent Process theory |
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| Class 18 March 4 |
Carefully complete Opponent Process theory and be sure to understand Hurvich & Jameson cancellation experiment in relation to their graphs of wavelength color appearances. | |||
| Class 19 March 6 |
Review for exam | |||
| Class 20 March 9 |
EXAM II | |||
| Class 21 March 11 |
The 6 topics covered on Exam 3 are indicated in upper case text from here to April 17. The course material pertinent to the topic is everything listed after what is in upper case until you get to the next upper case listing.EXAM 3 CATEGORY — NEUTRAL COLOR PERCEPTION — INCLUDES WALLACH, GILCHRIST, LIGHTNESS, LIGHTNESS CONSTANCY, ANCHORING PRINCIPLE
For now, READ ONLY to the top of p. 798 of Gilchrist’s paper. We’ll return to it later. Pay special attention to the “ratio principle” of Wallach. Contrast: Neutral colorPurves Demo that you saw in videos at the beginning of the course. |
Black and white demo on screen — where does “black” come from?Nonspectral colors — Black and white, and all the grays in between are called neutral colors.
Perceptual Constancy in color and lightness. Black and White. Classic work of Wallach and recent work of Gilchrist. Continuing introduction of neutral colors, lightness, and lightness constancy Appearance of one area can depend heavily on the appearance of neighboring areas. What does it mean to say the luminance is ambiguous? Review the main points of Gilchrist |
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| Class 22 March 13Next class is after spring break |
Gilchrist paper on lightness perceptionIn order to dramatize the concept of luminance (amount of light at the eye), which is so important in Gilchrist, we will use our own luminance meter in class.
Tufte signs This picture of the signs on Tufte’s estate shows pictorial or retinal adjacency, but they signs are on different planes (at different distances from the observere) in the world. This means that they are adjacent at the eye, but NOT in the world. |
Moving ahead to get back to hues and “color constancy.” | ||
| Class 23 March 23 |
Last time we learned about luminance and its measurement with a luminance meter. Basically LUMINANCE is a measure of amount of light coming to the eye from a place on a surface.Gilchrist paper on lightness perception If you cannot get the whole paper from this link, go to the class Moodle site, Topic 4 to find a copy.
Gilchrist full PowerPonit on lightness perception and the ANCHORING problem |
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| Class 24 March 25 |
EXAM 3 CATEGORY — COLOR CONSTANCY, LAND’S MONDRIAN DEMONSTRATION, LAND’S RETINEX THEORY, BE ABLE TO FOLLOW LAND PAPER
Read: Land’s Retinex Paper Illustrating Land’s “Mondrian” experiment Units of light measurement in Land’s Retinex demonstrations are in milliwatts per steradian per square meter. So here’s a steradian. Real Mondrians paintings look like. |
Color constancy with Edwin Land.COLOR CONSTANCY
Land’s Red – White experiment More Land. I now give you the option of reviewing the black and white slides we saw in class, for the Land Red – White demo. Elaborating the Land Red and White experiment to segue into Retinex demonstrations and theory. Retinex theory |
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| Class 25 March 27 |
Land himself explaining demos (VIDEO HAS BEEN REMOVED) For our purposes, think of this beginning at the 3:39 mark in the video.Details of Retinex demonstration, with Mondrians
Harvard art project with light on Rothko paintings Land Mondrian Homework (ONLINE POWERPOINT) Due next Wednesday at 5 pm |
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| Class 26 March 30 |
Land’s full Retinex Theory [See links for March 25]PhotoFlair by TruView uses the retinex algorithm and advertises that it comes from NASA | |||
| Class 27April 1 | Land final | Reviewing Land’s neutral color algorithmLand Homework due | ||
Camera! |
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| Class 28 April 3 |
EXAM 3 CATEGORY — VISUAL PHYSIOLOGY. LAYERS OF RETINA. HOW LATERAL INHIBITION WORKS. RECEPTIVE FIELDS — GANGLION, HUBEL & WIESEL WORK ON V1 IN VISUAL CORTEX (SIMPLE, COMPLEX, END-STOPPED CELLS AND THEIR RECEPTIVE FIELDS). HOW ARE THESE EXPERIMENTS DONE?The retina from your online book on the eye.
Orienting slides, retina to cortex through lateral geniculate nucleus (LGN)
Hubel book Good resource |
Class today concentrates on the work of Kuffler and the discovery of RECEPTIVE FIELDS. In Kuffler’s case, we were looking at the receptive fields of retinal ganglion cells — ON-CENTER, OFF SURROUND; and OFF-CENTER, ON SURROUND. We foreshadowed the Nobel prize of Hubel & Wiesel. | ||
| Class 29 April 6 |
Advising WeekHubel & Wiesel Discovery
Visual Cortex in online Webvision book Hubel & Wiesel simple cell video Diagrams of areas of visual cortex from George Mather. Lateral inhibition slides (ONLINE POWERPOINT-NOT TRANSFERABLE) Chevreul Illusion demo. Also called “Mach Bands.” This is most famously presented as an example of Mach Bands, but some people prefer Chevreul because he was first |
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| Class 30 April 8 |
Chapter 3 of Hubel book is excellent review of the brain study that we have done to here.Chapter 4 of Hubel book covers the primary visual cortex
EXAM 3 CATEGORY — RECEPTIVE FIELD PROPERTIES BEYOND V1 — GROSS, QIAN QUIROGA |
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| Class 31 April 10 |
Photo sample Where are lines? Part of photo Blow-up within part of photo Lines?Charles Gross’s description of discoveriesGross and colleagues’ face workQuian Quiroga et alFigure 1 from Quian Quiroga et alSignal Detection graphs in Quian Quiroga et al Figure showing MTL brain region Brain wiring debate: Seung vs. Movshon. Introductions last for a while. Really begins about 10 minutes in. There are many references to C. elegans in the video. Here is what that’s about |
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| Class 32 April 13 |
Quian Quiroga et alFigure 1 from Quian Quiroga et al | |||
Gestalt Psychology! |
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| Class 33 April 15 |
EXAM 3 CATEGORY — GESTALT PSYCHOLOGYWertheimer (1923) on Gestalt psychology
Same as above Better view of text, not of diagrams. There are two papers about Gestalt psychology by Mary Henle on the Moodle site. They are required reading! |
Gestalt is NOT someone’s nameGestalt theme: Organization in Perception. Need to EXPLAIN THE OBVIOUS.
Gestalt Mantra: “The whole is greater than the sum of its parts” |
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| Class 34 April 17 |
Gestalt psychology and binocular vision, culminating in the work of Bela JuleszEXAM 3 CATEGORY — BINOCULAR VISION — STEREOPSIS AND SIGNIFICANCE OF JULESZ WORK FOR GESTALT THEORY OF BINOCULAR FUSION
Seeing with 2 eyes — Bela Julesz and binocular vision Binocular vision tutorial in pdf. Random Dot Stereograms as puzzles for the Gestalt account of binocular fusion |
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Introducing Ecological PsychologyAction! |
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| Class 35 April 20 |
FINAL EXAM CATEGORY — ECOLOGICAL PSYCHOLOGY –FRAMES OF REFERENCE, OPTIC FLOW; ANSWERS TO BEAU LOTTO AND RICHARD GREGORYIntroduction to Ecological Psychology | Motion — What is the classical ambiguity of motion perception when motion is treated as points on the retina? What is the ecological alternative? | ||
| Class 36 April 22 |
EXAM III | |||
| Class 37 April 24 |
From last time — maximum motion ambiguity when the eye is the frame of reference vs. increased specificity when the world is the frame of reference.Global Optic Flow — the geometric information for SELF-MOVEMENT in the environment. This is well illustrated in videos of airplane landings from the point of view of the pilot.
KLM Boeing B747-400 Landing St. Maarten David N. Lee constructed a SWINGING ROOM to study the perception of self-movement by manipulating GLOBAL OPTIC FLOW. Visual control of self-movement is important in simply maintaing upright posture, i.e. balance. Perception and Action Lee Film excerpt Entire Lee FilmBBC video on movement [Start at 1:14] From Gert-Jan Pepping’s YouTube collection. You can see some related videos in the same set. Dave Lee’s Perception Movement Action Research Consortium Barrie Frost Visual Neurophysiology of optic flow. Zoomquilt a good example of self motion through a stable environment. Optic flow is here — and more. Lee and Reddish on diving gannets Lee and students on the Long Jump Horizon Link Horizon photo. Most of class this day was about the horizon relations — determining the direction of the point of view, and the sizes of things relative to the height of the point of view. Gannet and Tau detail Lee’s tau is a relation at the eye that specifies time of gap closure (time to contact). Tau is only about the case of constant velocity. Falling under the force of gravity (like the gannets) involves acceleration, a consistent change of velocity. Lee’s idea in the paper is that the gannets still monitor tau, but that they keep checking it until tau reaches a key value that he calls tau margin. Lee and Reddish on diving gannets |
Self-motionOptic Flow
Tau perception as answering questions After optic flow, Dave Lee’s Tau Tau Gannets Braking Long Jump The view of the plane landing |
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| Class 38 April 27 |
Review Lee Film, beginning with babies in swinging roomGannet and tau detail | More detail on tau.Introduction to Ecological Approach, emphasizing perceiving the environment, ecological realism.
Seeing yourself move in the world |
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| Class 39 April 29 |
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FINAL EXAM Monday MAY 4, 9 a.m. Regular Classroom |
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Ecological Psychology and Homeokinetics 
