Understanding Psychology (10th Ed)

opponent-process theory of color 
vision
The theory that receptor cells 
for color are linked in pairs, working 
in opposition to each other.
FIGURE 8 
Stare at the dot in this fl ag 
for about a minute and then look at a 
piece of plain white paper. What do you 
see? Most people see an afterimage that 
converts the colors in the fi gure into the 
traditional red, white, and blue U.S. fl ag. 
If you have trouble seeing it the fi rst 
time, blink once and try again.
Study Alert
Keep in mind that there are 
two explanations for color 
vision: trichromatic and 
opponent-process 
theories.
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R E C A P / E V A L U A T E / R E T H I N K
K E Y T E R M S
R E C A P
What basic processes underlie the sense of vision?
• Vision depends on sensitivity to light, electromagnetic 
waves in the visible part of the spectrum that are either 
refl ected off objects or produced by an energy source. 
The eye shapes the light into an image that is trans-
formed into nerve impulses and interpreted by the 
brain. (p. 104)
• As light enters the eye, it passes through the cornea, 
pupil, and lens and ultimately reaches the retina, where 
the electromagnetic energy of light is converted to nerve 
impulses for transmission to the brain. These impulses 
leave the eye via the optic nerve. (p. 105)
• The visual information gathered by the rods and cones is 
transferred via bipolar and ganglion cells through the 
optic nerve, which leads to the optic chiasm—the point 
where the optic nerve splits. (p. 106) 
How do we see colors?
• Color vision seems to be based on two processes 
described by the trichromatic theory and the opponent-
process theory. (p. 111)
• The trichromatic theory suggests that there are three 
kinds of cones in the retina, each of which is responsive 
to a certain range of colors. The opponent-process theory 
presumes pairs of different types of cells in the eye that 
work in opposition to each other. (p. 111)