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The tricolor and the opponent-process mechanisms work together to produce color vision. When
light rays enter the eye, the red, blue, and green cones on the retina respond in different degrees,
and send different strength signals of red, blue, and green through the optic nerve. The color
signals are then processed both by the ganglion cells and by the neurons in the visual cortex
(Gegenfurtner & Kiper, 2003). [7]
Perceiving Form
One of the important processes required in vision is the perception of form. German
psychologists in the 1930s and 1940s, including Max Wertheimer (1880–1943), Kurt Koffka
(1886–1941), and Wolfgang Köhler (1887–1967), argued that we create forms out of their
component sensations based on the idea of the gestalt, a meaningfully organized whole. The idea
of the gestalt is that the “whole is more than the sum of its parts.” Some examples of how gestalt
principles lead us to see more than what is actually there are summarized inTable 4.1 "Summary
of Gestalt Principles of Form Perception".
Table 4.1 Summary of Gestalt Principles of Form Perception
Principle Description Example Image
Figure and
ground
We structure
input such that
we always see a
figure (image)
against a ground
(background).At right, you may see a vase
or you may see two faces,
but in either case, you will
organize the image as a
figure against a ground.Figure 4.1