In Freud's psychoanalytic theory of personality, the pleasure principle is the driving force of the id that seeks immediate gratification of all needs, wants and urges. In other words, the pleasure principle strives to fulfill our most basic and primitive urges, including hunger, thirst, anger, ...
The young-Helmholtz trichromatic theory(The Early Theory That Explains How We Perceive Color) There are three receptors in the retina that are responsible for the perception of color. One receptor is sensitive to the color green, another to the color blue, and a third to the color red. The ...