The effects of repeated advertising exposures depend on the size of the interval, or space, between ad exposures. A meta-analysis of 97 verbal learning studies identified several stimulus characteristics and learning context factors that interact with stimulus spacing to facilitate memory for repeated information. The majority of the findings are consistent with the predictions of two enhanced processing explanations of learning--the retrieval hypothesis and the reconstruction hypothesis. These two hypotheses predict that an effective repetition strategy should encourage incidental processing during one presentation of the material and intentional processing during the other presentation of the material, but the hypotheses differ about the optimal order of these two types of processing. Thus, the most effective repetition strategy may be a combination of spaced exposures that alternate in terms of media that are involving (e.g., television commercials) and less involving (e.g., billboards, product placements). Copyright 2003 by the University of Chicago.