In this video, we discuss how humans perceive color. We learn about different, competing theories of color vision and we experience a few demonstrations (e.g., afterimages) that illustrate the strengths and weaknesses of these theories.

Light: A form of electromagnetic energy that has a wavelength, which determines its color.

Trichromatic Theory: A theory of how we perceive color which suggests that our color vision is based on three primary colors—red, green, and blue—since we have three different kinds of cones that are each maximally sensitive to the different wavelengths associated with these colors.

Monochromats: People with a specific form of color blindness in which they only have 1 out of the 3 different types of cones, resulting in total color blindness (monochromacy affects 1 in 30,000 people).

Dichromats: People with a specific form of color blindness in which they only have 2 out of the 3 different types of cones, resulting in partial color blindness (e.g., redgreen color blindness).

Opponent Process Theory: Another theory of color vision which suggests that we perceive colors in terms of three pairs of opposing colors: red vs. green, blue vs. yellow, and black vs. white; afterimages always appear in opposing colors, providing evidence for this theory.