ABSTRACT
A representation stands for something else in its absence. Internal representations are used to store information in memory, and there is debate about what form they take. There is some agreement that images and propositions are necessary forms of representation. Internal representations can similarly be divided into two classes: analogical representations and propositional representations. The dual coding theory employs different memory codes for verbal and sensory information; verbal representations are called logogens and sensory representations are called imagens. The function of mental images is a matter of some debate, but when people are asked to make use of them they behave as though the image was like any other percept. According to the propositional hypothesis, mental images are by-products of cognitive activity, not the basis for it. Images are representations of specific objects and include many of their perceptual properties, while mental models are more abstract and generalized analogical representations of objects, and are rather like prototypes.
