Symbols and icons in diagrammatic representation

The distinction between symbolizing, i.e., representing concepts or propositions, and simulating allows a simple description of (a) representations where symbolizing and simulating coincide ("iconic symbols", like in pictograms and onomato-poetic words), (b) representations realizing simulating and symbolizing functions by separate elements (as in charts and graphs), and (c) representations combining figurai symbols with linguistic symbols, such as logical pictures. These figurai symbols seem to derive their form from spatial metaphors. A more specific assumption was tested in two experiments: the more precise the mapping between logical picture and spatial metaphors in the text, the higher the efficiency of this two-dimensional analogy in reducing the cognitive load of the text. The experiments had to meet the requirement of an equivalent "meaning " of the text-picture combinations to be compared. In both experiments the data of the guessing-tests used for measuring the "cognitive load" showed the expected tendency.