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PSYCH306: Sensation and Perception

Unit 4: The Visual System: Perceptual Mechanisms   In this unit, we will look at how humans are able to see and interpret complex stimuli like color, motion, and multiple dimensions. Note that not all animals are capable of seeing these stimuli; the human ability to do so has been instrumental in our evolution. Over the course of this unit, keep in mind what you have learned about the different aspects of our visual pathways, asking how they might play a role in the interpretation of these stimuli.

Unit 4 Time Advisory
This unit should take you 20.5 hours to complete.

☐    Subunit 4.1: 3.5 hours

☐    Subunit 4.2: 3.5 hours

☐    Subunit 4.3: 3 hours

☐    Subunit 4.4: 3 hours

☐    Subunit 4.5: 3 hours

☐    Subunit 4.6: 2.5 hours

☐    Subunit 4.7: 2 hours

Unit4 Learning Outcomes
Upon successful completion of this unit, students will be able to:

  • explain the fundamental aspects of the perception of color;
  • explain the fundamental aspects of the perception of movement;
  • explain the fundamental aspects of the perception of depth;
  • explain the relationship between visual perception and cognition; and
  • explain how visual illusions reveal important details about visual perception.

4.1 Color   - Reading: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” (PDF)
 
Instructions: Read chapter 6. NOTE: This document is in a continuous state of updating. Please ignore the internal notes, such as “[need illustration here],” for example. Most of the referenced figures are included at the end of the document; it is okay if not all the figures are available. ADDITIONAL NOTE: This reading applies to all subsections of section 4.1.
 
Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.1.1 What is Color? Light Intensity and Wavelength   Note: The reading assigned beneath subunit 4.1 also covers this subunit.

  • Interactive Lab: Molecular Expressions’ “Basic Electromagnetic Wave Properties” Link: Molecular Expressions’ “Basic Electromagnetic Wave Properties” (HTML)
     
    Instructions: Click the link above to navigate to the website. In the animation, use the sliders to see the relationship between frequency, wavelength, color, and intensity.
     
    Terms of Use: Please respect the copyright and terms of use included on the above webpage.

4.1.2 Wavelengths and Perception: The Creation of Color   Note: The reading assigned beneath subunit 4.1 also covers this subunit.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 6.x: Dimensions of Color” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 6.x: Dimensions of Color” (JAVA)
     
    Instructions: Click the link above or the link on page #1 of the “Chapter 6” PDF document for the embedded activity called “Interactive Illustration 6.x: Dimensions of Color.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that gives you control over the psychological dimensions of light. Follow the directions in the “Chapter 6” PDF document to demonstrate how these dimensions affect what colors you perceive.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.1.3 The Difference Between Lights and Pigments   Note: The reading assigned beneath subunit 4.1 also covers this subunit.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x: Newton’s Prism Experiment” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x: Newton’s Prism Experiment” (JAVA)
     
    Instructions: Click the link above or the link on page #3 of the “Chapter 6” PDF document for the embedded activity called “Experiment 6xs: Newton's Prism Experiment.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that gives you control over the positions of two prims, in relation to a white light source on the left. Double-click the prisms to move them in and out of the beam of white light.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 6.x: Additive and Subtractive Color Mixing” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive 6.x: Additive and Subtractive Color Mixing” (JAVA)
     
    Instructions: Click the link above or the link on page #4 of the “Chapter 6” PDF document for the embedded activity called “Interactive Illustration 6.x: Additive and Subtractive Color Mixing.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that gives you control over three sources of light. Follow the directions in the “Chapter 6” PDF document to demonstrate how additive (lights) and subtractive (pigments) color mixtures work.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.1.4 Different Colors   Note: The reading assigned beneath subunit 4.1 also covers this subunit.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Effect of Illuminant” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x: Effect of Illuminant” (JAVA)
     
    Instructions: Click the link above or the link on page #4 of the “Chapter 6” PDF document for the embedded activity called “Experiment 6.x, Effect of Illuminant.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that gives you control over how a photograph is illuminated. Follow the directions on page #5 of the PDF document to view and understand this issue.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 6.x: 1931 CIE Diagram” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 6.x: 1931 CIE Diagram” (JAVA)
     
    Instructions: Click the link above or the link on page #11 of the “Chapter 6” PDF document for the embedded activity called “Interactive Illustration 6.x, 1931 CIE Diagram.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that illustrates the international system for specifying different colors.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.1.5 Chromatic and Achromatic Color   Note: The reading assigned beneath subunit 4.1 also covers this subunit. This information is mostly in section III about the idea of color opponency. It is very important to understand this concept.

4.1.6 Brightness vs. Saturation   Note: The reading assigned beneath subunit 4.1 also covers this subunit. Colors can have both intensity (brightness) and richness/depth (saturation). The first section of the assigned reading covers these concepts.

4.2 Seeing Color   4.2.1 Trichromacy Theory   - Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, The Trichromatic Theory” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, The Trichromatic Theory” (JAVA)
 
Instructions: Click the link above or the link on page #11 of the “Chapter 6” PDF document for the embedded activity called “Experiment 6.x, The Trichromatic Theory.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that illustrates trichromacy. Follow the directions on page #11 of the PDF document to view and understand this issue.
 
Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.2.2 The Importance of Metamers   Note: The reading assigned beneath subunit 4.2.1 also covers this subunit.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Color Matching Experiment” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Color Matching Experiment” (JAVA)
     
    Instructions: Click the link above or the link on page #5 of the “Chapter 6” PDF document for the embedded activity called “Experiment 6.x, Color Matching Experiment.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that gives you control over the color matching stimuli. Follow the directions on page #5 of the PDF document to try the color matching procedure.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.2.3 Opponent-Process Theory   Note: The reading assigned beneath subunit 4.2.1 also covers this subunit.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Complementary Colors” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Complementary Colors” (JAVA)
     
    Instructions: Click the link above or the link on page #13 of the “Chapter 6” PDF document for the embedded activity called “Experiment 6.x, Complementary Colors.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that illustrates the concept of complementary colors. Follow the directions on page #13 of the PDF document to view and understand this phenomenon.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Early Color Vision” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Experiment 6.x, Early Color Vision” (JAVA)
     
    Instructions: Click the link above or the link on page #16 of the “Chapter 6” PDF document for the embedded activity called “Experiment 6.x, Early Color Vision.” If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that illustrates the combination of trichromacy and opponent process theory. Follow the directions on pages #16-#18 of the PDF document to view and understand this approach.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.2.4 Color Constancy   - Reading: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” (PDF)
 
Instructions: Read from “Color Constancy” on page 9.8 to “Visual Illusions” on page 9.10. NOTE: This document is in a continuous state of updating. Please ignore the internal notes, such as “[need illustration here],” for example. Most of the referenced figures are included at the end of the document; it is okay if not all the figures are available.
 
Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 9.x, Light and Color” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 9.x, Light and Color” (JAVA)
     
    Instructions: If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that gives you control over how a photograph is illuminated.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 9.x, Color Aftereffects” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception: Interactive Illustration 9.x, Color Aftereffects” (JAVA)
     
    Instructions: If you have installed the JAVA plug-in (see page #2 of this course), clicking the embedded link will open a page that illustrates color aftereffects. Click the text link “Instructions” in the upper left corner and follow the directions.
     
    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.2.5 Opponent and Double-Opponent Processes   - Reading: The University of Utah: Peter Gouras’ “Color Constancy and Double Opponency” Link: The University of Utah: Peter Gouras’ “Color Constancy and Double Opponency” (HTML)
 
Instructions: Click the link above to navigate to the web page and read this section in its entirety.
 
Terms of Use: Please respect the copyright and terms of use included on the above document and webpage.

4.2.6 Deficits of Color Perception   Note: The reading assigned beneath subunit 4.2.1 also covers this subunit. See section IV, paying special attention to the relationship between color blindness and the opponent process theory of color vision.

4.3 Motion   - Reading: Stanford University: Professor Alex Huk’s “Seeing Motion: Lecture Notes” Link: Stanford University: Professor Alex Huk’s “Seeing Motion: Lecture Notes” (PDF)
 
Instructions: Click the link above to navigate to the web page and read the entire page. Do not be concerned if some of the links to figures and illustrations do not work. NOTE: This reading applies to all subsections of section 4.3.
 
Terms of Use: This material has been hosted with the kind permission of Alex Huk.

4.3.1 What is Motion: Change in Position over Time   Note: The reading assigned beneath subunit 4.3 covers this subunit. Motion has direction and speed. Additionally, we can classify motion according to type. Be sure to review the various types of motion carefully.

4.3.2 Simple Translation   Note: The reading assigned beneath subunit 4.3 covers this subunit. This type of motion has to do with the simple picture that arrives at your retina.

4.3.3 Complex vs. Apparent Motion   Note: The reading assigned beneath subunit 4.3 covers this subunit. As the name suggests, apparent motion is not really motion at all. Be sure to consider why such phenomena help us understand motion perception.

4.3.4 Stroboscopic Motion   Note: The reading assigned beneath subunit 4.3 covers this subunit. This kind of motion also is not real motion. Can you imagine a world in which we could not experience stroboscopic motion?

4.3.5 Aftereffects of Motion   Note: The reading assigned beneath subunit 4.3 covers this subunit. Understand why watching movement in one scene can lead to the perception of movement in another, static scene.

4.3.6 Optic Flow   Note: The reading assigned beneath subunit 4.3 covers this subunit. Optic flow is about how images move across your retina as you move through the world. You should understand how this helps us navigate through our daily lives.

4.3.7 Induced Movement   Note: The reading assigned beneath subunit 4.3 covers this subunit. Have you ever felt like you were moving when the car next to you began to move? What does this phenomenon suggest about our perception of movement?

4.3.8 Object Motion   Note: The reading assigned beneath subunit 4.3 covers this subunit. Not all motion perception involves the movement of objects, but this is still one of the major features of how we perceive movement.

4.4 Seeing Motion   - Reading: Stanford University: Professor Alex Huk’s “Seeing Motion: Lecture Notes” Link: Stanford University: Professor Alex Huk’s “Seeing Motion: Lecture Notes” (HTML)
 
Instructions: Click the link above to navigate to the web page and read the entire page. Do not be concerned if some of the links to figures and illustrations do not work. NOTE: This reading applies to all subsections of section 4.4.
 
Terms of Use: This material has been hosted with the kind permission of Alex Huk.

4.4.1 Motion Detectors in the V1   Note: The reading assigned beneath subunit 4.4 covers this subunit. This portion of the reading covers the cortical processing of movement by detector cells in the primary visual cortex.

4.4.2 Directionally-Selective Receptors   Note: The reading assigned beneath subunit 4.4 covers this subunit. Be sure to watch the linked movie (see the link movie in section 2) for a demonstration of motion aftereffect.

4.4.3 The Extrastriate Area and Pattern Cells   Note: The reading assigned beneath subunit 4.4 covers this subunit. Area MT in the extrastriate contains movement-sensitive cells called pattern cells. Follow the various links in section 3 for additional information and demonstrations.

4.4.4 Extrastriate Area and Motion Aftereffects   Note: The reading assigned beneath subunit 4.4 covers this subunit. Not all motion perception involves the movement of objects, but this is still one of the major features of how we perceive movement.

4.4.5 Observer Motion: Relative Motion to Observer   Note: The reading assigned beneath subunit 4.4 covers this subunit. Follow the link in section 5 to see the optic flow field for a pilot landing a plane.

4.4.6 Changing Light Pattern in the Retina   Note: The reading assigned beneath subunit 4.4 covers this subunit. J.J. Gibson had an interesting perspective on the perception of movement. Try to integrate this with our earlier discussion of Gibsons ideas about sensation and perception.

4.4.7 Eye Movements   Note: The reading assigned beneath subunit 4.4 covers this subunit. Be sure you understand why it is important that our eyes move almost continuously.

4.4.8 Corollary Discharge   Note: The reading assigned beneath subunit 4.4 covers this subunit. Be able to answer the following question: Although our eyes are almost constantly moving, how do we perceive a basically steady world?

4.5 Seeing in Three Dimensions   - Reading: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” (PDF)
 
Instructions: Read chapter 8. NOTE: This document is in a continuous state of updating. Please ignore the internal notes, such as “[need illustration here],” for example. Most of the referenced figures are included at the end of the document; it is okay if not all the figures are available. ADDITIONAL NOTE: This reading applies to all subsections of section 4.5.
 
Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

  • Assignment: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” Link: Hanover College: Professor John Krantz’s “Experiencing Sensation and Perception” (PDF)
     
    Instructions: In turn, click on each of the interactive illustrations in chapter 8 and follow the directions. Please ignore the internal notes, such as “[need illustration here],” for example. Most of the referenced figures are included at the end of the document; it is okay if not all the figures are available. ADDITIONAL NOTE: This assignment applies to subsections 4.5.1-4.5.7.

    Terms of Use: The linked material above has been reposted by the kind permission of John Krantz, and can be viewed in its original form here. Please note that this material is under copyright and cannot be reproduced in any capacity without explicit permission from the copyright holder.

4.5.1 From 2-D Images to a 3-D Construction   Note: The reading and assignment assigned beneath subunit 4.5 cover this subunit. See especially section 1, which introduces the concept of depth as a perceptual phenomenon.

4.5.2 Monocular and Binocular Information   Note: The reading and assignment assigned beneath subunit 4.5 cover this subunit. Is it possible to perceive depth if you have vision in only one eye? Be sure you are able to address this question.

4.5.3 Depth Clues   Note: The reading and assignment assigned beneath subunit 4.5 cover this subunit. Not all motion perception involves the movement of objects, but this is still one of the major features of how we perceive movement.

4.5.4 Disparity: The Different Views of our Eyes   Note: The reading assigned beneath subunit 4.5 covers this subunit. How does the fact that each of our eyes has a slightly different view of the world provide information on depth? What do you see when you close first one eye and then the other?

4.5.5 Uncrossed vs. Crossed Disparity   Note: The reading and assignment assigned beneath subunit 4.5 cover this subunit. The reading covers this topic about halfway down on page #8.

4.5.6 Correspondence Problems: Diplopia and Binocular Rivalry   Note: The reading and assignment assigned beneath subunit 4.5 cover this subunit. Sometimes the images the brain receives from the two eyes do not "merge" properly. See page #10 of the assigned reading.

4.5.7 Stereovision in the Brain   Note: The reading and assignment assigned beneath subunit 4.5 cover this subunit. This perceptual phenomenon is referred to as stereopsis in the assigned reading, and is covered starting on page #7.

4.5.8 Disparity-Selective Neurons   - Reading: Reading: Webvision: Matthew Schmolesky’s “The Primary Visual Cortex” Link: Webvision: Matthew Schmolesky’s “The Primary Visual Cortex” (HTML)
 
Instructions: Click the link above to navigate to the web page. Scroll down to the section titled “Binocularity and Binocular Disparity” and read this in its entirety.
 
Terms of Use: Please respect the copyright and terms of use included on the above document and webpage.

4.5.9 Size and Shape Constancy   - Reading: Reading: SAP Design Guild Resources: “Perceptual Constancy” Link: SAP Design Guild Resources: “Perceptual Constancy (HTML)
 
Instructions: Click the link above to navigate to the web page and read it in its entirety.
 
Terms of Use: Please respect the copyright and terms of use included on the above document and webpage.

4.6 Object Recognition   - Reading: Stanford University: Professor Alex Huk’s “Object and Face Recognition: Lecture Notes” Link: Stanford University: Professor Alex Huk’s “Object and Face Recognition: Lecture Notes” (PDF)
 
Instructions: Click the link above to navigate to the web page and read the entire page. Do not be concerned if some of the links to figures and illustrations do not work. NOTE: This assignment applies to all subsections of section 4.6.
 
Terms of Use: This material has been hosted with the kind permission of Alex Huk.

4.6.1 Early Models: Template Matching and Feature Analysis   Note: The reading assigned beneath subunit 4.6 covers this subunit. See section 1 for a general discussion on these early models of object recognition.

4.6.2 Geon Theory   Note: The reading assigned beneath subunit 4.6 covers this subunit. This is not about a race of aliens from Star Trek! Researchers view geons as combinations of the basic building blocks necessary for object recognition.

4.6.3 Single-Model Axis, Component Axes and 3D Model Match   Note: The reading assigned beneath subunit 4.6 covers this subunit. Be sure to understand the assumptions and limits of these ideas about object recognition.

4.6.4 View-Dependent Recognition   Note: The reading assigned beneath subunit 4.6 covers this subunit. This idea is that object recognition depends on the context. It is easier to recognize an object in a familiar context as opposed to a novel context. Think about your own experiences as you read about this idea.

4.6.5 Gestalt Theories and Perceptual Organization   Note: The reading assigned beneath subunit 4.6 covers this subunit. The Gestalt idea is that you cannot separate the parts from the whole. When we look at a wooded mountainside, we see the forest first, and not the individual trees. According to the Gestalt (German for the whole) view, the relationship between the parts guides our perception of the whole.

4.6.6 Is Facial Recognition Special? The Importance of Familiarity   Note: The reading assigned beneath subunit 4.6 covers this subunit. There is good evidence suggesting that humans are hard wired to recognize faces. Think about whether you have observed this in infants and small children.

4.6.7 Agnosias: Impaired Recognition   Note: The reading assigned beneath subunit 4.6 covers this subunit. As always, perceptual failures can help us discover how normal” perception works. Think about what the various agnosias might tell us about object recognition.

4.7 “Failures” of Visual Perception: Visual Illusions   - Web Media: Michael Bach’s “88 Visual Phenomena & Optical Illusions” Link: Michael Bach’s “88 Visual Phenomena & Optical Illusions” (HTML and Adobe Flash)
 
Instructions: Click the link above to navigate to the web page. Explore and enjoy the many visual illusions and interesting effects. Read the explanations for each, and relate this to what you have learned about the visual system.
 
Terms of Use: Please respect the copyright and terms of use included on the above document and webpage.