Before revision: Propositional representation is the psychological theory, first developed in 1973 by Dr. Zenon Pylyshyn, that mental relationships between objects are represented by symbols and not by mental images of the scene.<ref>Elport, Daniel "Cognitive Psychology and Cognitive Neuroscience", Wikibooks, July 2007, accessed March 07, 2011.</ref> For example, a propositional network describing the sentence "John believes that Anna will pass her exam" is illustrated in Figure 1.
After revision: Propositional representation is the psychological theory, first developed in 1973 by Dr. Zenon Pylyshyn, that mental relationships between objects are represented by symbols and not by mental images of the scene.<ref>Elport, Daniel "Cognitive Psychology and Cognitive Neuroscience", Wikibooks, July 2007, accessed March 07, 2011.</ref> Examples A propositional network describing the sentence "John believes that Anna will pass her exam" is illustrated