Previous studies examining expertise have used a wide range of methods. Beyond characterizing expert and novice behavior in different contexts and circumstances, many studies have examined the processes that comprise the behavior itself and, more recently, processes that comprise training and practice that develop expertise. Other studies, dating back more than 50 years, have used various recall memory tasks to compare experts and novices. In this article, we describe another method for investigating expertise that has its origin in the study of "change blindness," a phenomenon within the field of visual cognition. We demonstrate how an incidental change detection paradigm can be used in the context of introductory physics in a way that allows for inferences regarding the formation of mental representations about physical situations. Possible uses in future learning sciences research are discussed. (Contains 3 tables, 4 figures, and 2 footnotes.)