Sensation and Perception 9th Edition by Bruce Goldstein

Exercise 1

A person with normal color vision is called a trichromat. This person needs to mix three wavelengths to match all other wavelengths and has three cone pigments. A person who is color deficient is called a dichromat. This person needs only two wavelengths to match all other wavelengths and has only two operational cone pigments. A tetrachromat needs four wavelengths to match all other wavelengths and has four cone pigments. If a tetrachromat were to meet a trichromat, would the tetrachromat think that the trichromat was color deficient? How would the tetrachromat's color vision be "better than" the trichromat's?
Figure In a color-matching experiment, the observer adjusts the amount of three wavelengths in one field (right) so that it matches the color of the single wavelength in the other field (left).