Psychology 3215

Questions about Vision to Ponder before Test 3


1. What is the relationship between wavelength and color? Know the general wavelengths that I used to indicate a color.  450 nm (alone) produces what?  550 nm?  650 nm?

2. What are spectral colors? What are nonspectral colors?  Are nonspectral colors an illusion or are they real?  What are metamers?

3. Is white a color? Is white a wavelength? Is purple a color? Is purple a wavelength? Is yellow a color? Is yellow a wavelength?

4. What is the difference between hue, saturation, and brightness? What is the difference between hue and color? How many colors can we see?

5. Understand how additive and subtractive color mixing work in daily life. Explain how to make a T-shirt look purple, using additive and subtractive color mixing.

6. Where do we encounter additive and subtractive color mixing in daily life?

7. Understand trichromatic theory. What did Helmholtz do? What did he find?

8. Understand opponent process theory. What did Hering consider to be important evidence supporting his objections to trichromatic theory?

9.  How did Hering's hypothetical color receptors work?

10. Whose theory was correct, Helmholtz or Hering?

11. Know the general location and shape of the spectral sensitivity curves for the three types of cone receptors in humans.

12. Why do we label the cones as Short, Medium, & Long wavelength detectors instead of Blue, Green, and Red detectors?

13. At the level of activity of the cones, how do we explain seeing white, blue, purple, yellow, and green? (Draw it, like we did in class.)

14. What is the difference between a Trichromat and a Dichromat?

15. What causes dichromat color blindness? Identify the three types of color blindness. What is the physiological problem?

16. What happens to the color world of individuals with each type of color blindness? What colors do they see, relative to people with standard color vision?  

17. What is a binocular depth cue? A monocular depth cue?  How can you tell the difference between a binocular depth cue and a monocular depth cue?

18. Binocular cues to depth/spatial localization.  Be able to identify the difference between corresponding and noncorresponding retinal points in looking at a scene. What conditions produce each?

19. What is the horopter? Where is the horopter located in space? What is special about the retinal images of objects that are on the horopter? What is Panum's Area?  Where is the Area of Pizza?  [last question is a joke.]

20. Diagram two objects, one of which is in front of the horopter and another object that is beyond the horopter, and indicate where their retinal images will be located. Understand the difference between crossed and uncrossed disparity.

21. Imagine that you are sitting in your apartment and you look at various people/objects. Explain how retinal disparity changes as you look about the room.  How do those changes contribute to your understanding of spatial relationships?

22. What is a binocular sterogram?  How does it work?

23. What is an anaglyph?  How does it work?