The purpose of this chapter is to focus attention on what is termed representational competence and to argue that such competence is necessary, but not sufficient, for effective cognitive functioning . To foreshadow the discussion, I provide a brief definition of representational competence. It refers to the understanding and utilization of a fundamental rule to the effect that knowledge presented in various forms (e.g., pictures, words, signs) still retains its intrinsic meaning in spite of variations in form of presentation . For example a cup, whether presented in pictorial form or as a three-dimensional item, still retains its intrinsic identity as a "cup." A picture of a person retains the intrinsic identity of the person even if the person is presented only in the picture. Representational competence is a form of conservation, in which the meaning of an instance is retained in spite of change in form or symbolic level. I offer the term conservation oj meaning to be added to the lexicon of conservation types .