1. Color Vision: Sensing a Colorful World
Psychological experience of vision
Trichromatic Theory
Opponent-Process Theory

2. The stimulus for vision is LIGHT
Light travels in the forms of waves.
Waves affect three aspects of our visual world:
Hue, brightness, and saturation.
All 3 are PSYCHOLOGICAL DIMENSIONS OF VISUAL EXPERIENCE.

3. Hue “Experts estimate that we can distinguish perhaps as many as 10 million colors.“ Wyszecki, Gunter. Color. Chicago: World Book Inc, 2006: 824.
Specified by color names
Hue is related to the wavelength of light.

4. Brightness
Is related to the amount, or intensity, of the light an object emits or reflects.
Height of the wavelength.
The more light an object reflects, the brighter it appears.

5. Saturation (colorfulness)
Related to the complexity of the light, how wide or narrow the wave is.

6. Trichromatic Theory proposed by T. Young and H. vov Helmholtz
Our eyes detect 3 primary colors
-red, blue, and green
Three receptors (cones) with differing sensitivities to different light wavelengths.
+ People can see all the colors of the rainbow because the eye does its own “color mixing” by varying the ratio of neural activity among these three types of receptors

7. Wavelengths of light
Blue-violet cones are most sensitive to short wavelengths of light

8. Wavelengths of light
Green cones are most sensitive to middle wavelengths

9. Wavelengths of light
Red cones are most sensitive to long wavelengths.

10. Color Blindness
Encompasses a variety of deficiencies in the ability to distinguish among colors.
Occurs much more frequently in males than in females
Dichromats (10% of men and 1% of women) they make do with only two types of color receptors.
Receptors may be insensitive to red, green, or blue (latter is rare).

11. Opponent Processing Theory (Ewald Hering)
Assumes that the visual system treats pairs of colors as opposing or antagonistic.
Yellow vs. Blue
Red vs. Green
Black vs. White
Black-white receptors detect brightness or shades of gray

14. O-P theory helps to explain…
Afterimage effect:
Stare at a blue circle for a while, you see a yellow circle briefly on a white sheet of paper.

15. O-P Theory
explain why dichromats typically find it hard to distinguish either green from red or yellow from blue.

16. Monochromates
Rare disorder in which a person can not detect any colors. Respond only to shades of light and dark.