The mere exposure effect is a phenomenon in which repeatedly presented stimulus are evaluated positively than unrepeated stimuli. The purpose of this article is to discuss the importance of internal representation in the mere exposure effect. At first, I briefly reviewed previous studies of the mere exposure effect in the viewpoint of a perceptual fluency model. Then, I introduced the classical and recent studies showing the importance of internal representation in the mere exposure effect. Finally the importance of internal representations were discussed based on our recent study indicating the mere exposure effect for visual image.
The present study investigated whether a mentally created visual image is retained in a visuospatial sketchpad or an episodic buffer in a multi-component model of working memory（Baddeley, 1986）. Functions of the episodic buffer require cognitive resources of the central executive. Four experiments were introduced here. Results in these experiments showed that a mentally created visual image was retained in the episodic buffer, not in the visuospatial sketchpad. On the other hand, perceptually encoded visual information was retained in the visuospatial sketchpad. Interestingly, even though both the created image and the perceptual information are to be retained in the form of visual representation, each type of visual representation involves different component. It could be argued that retaining a mentally created visual image continually requires mental manipulations（e.g., adjusting the size to fit in a mental space）. However, mental manipulation during the retention of perceptually encoded visual information would not be required if the information is recalled just as it is. This may be the reason why the created image is retained in the episodic buffer.