Multiple symbol systems: Learning with text and pictures. Orthographic symbols are, of course, not the only ones available to books. Pictures and diagrams are used in books from primers to college textbooks to technical manuals. But, how do readers use pictures? What is the cognitive effect of pictures in combination with text? And, how does the stability of these symbols, as presented in books, influence this process compared to another medium, say television, which presents linguistic and pictorial symbols in a transient way? This last, comparative issue will be directly addressed in the subsequent section on learning with television. The following section examines the cognitive effects of pictures and text.