Final answer:
The trichromatic theory of color vision explains that three types of cones in the retina, each sensitive to red, green, or blue light, combine signals to allow us to perceive a wide range of colors. This theory applies at the retinal level, while the opponent-process and retina theories describe subsequent processing in the visual system.
Step-by-step explanation:
Trichromatic Theory of Color Vision
The trichromatic theory of color vision explains how humans perceive color through the interaction of three types of cones in the retina. These cones correspond to the three primary colors: red, green, and blue. According to the theory, these cones are sensitive to different wavelengths of light, and it is their combined activity that enables us to see a wide spectrum of colors. The theory suggests the retina processes the color vision signals which are then relayed to the brain.
Further processing in the visual system aligns with the opponent-process theory. This accounts for the phenomena such as negative afterimages, where colors are perceived in opposite pairs, and certain color combinations like greenish-reds or yellowish-blues are not experienced. Finally, the retina theory builds on the trichromatic theory, acknowledging the sophisticated information obtained through the comparison of the signals from the three cone types.
These theories are not mutually exclusive but rather describe the color vision process at different stages, from the initial input in the retina to the higher-level processing in the brain, resulting in our complex and nuanced perception of colors.