3.5 : 色覚

Researchers have developed two theories to explain color vision.

The trichromatic theory suggests that color perception arises from three types of cone receptors in the retina – red, blue, and green, each sensitive to a different range of wavelengths.

These cones respond to different wavelengths of light, and color perception is based on the relative responses of red, blue, and green cone cells.

The study of color blindness supports the trichromatic theory. Most people with color blindness can see some colors but not others, depending on which cone type is inoperative.

The opponent-process theory suggests that the visual system cells respond to color pairs – red-green, blue-yellow, as well as a pair that processes brightness differences. A cell excited by one color is inhibited by its paired color. This theory explains afterimages, where staring at one color leads to seeing its opposite color due to a rebound effect.

Both the trichromatic and opponent-process theories are correct as the eye and the brain use both methods to code colors.

The cones in the retina connect to ganglion cells, converting the three-color code into the opponent-process code.