People are naturally very visually oriented.
Not only are their eyes very sophisticated, but the image processing centres of their brain are extremely adept at perceiving and interpreting even the most subtle visual patterns. This is why people have no problem looking at an abstract two-dimensional shape on a flat page and immediately recognizing it as representing some real world object. Graphic design depends upon this ability and takes advantage of the fact that visual experiences can elicit emotional reactions. This allows visual imagery to create impressions in peoples minds that effectively communicate ideas by nonverbal means. In this respect graphic design shares similarities with fine art.