The results of the bulk of crowding research over the past decade clearly indicate the need to identify the conceptual dimensions that determine people’s percep­ tions of being crowded. One must distinguish crowding-a perceived and subjec­ tive state-from environmental attributes commonly used to describe situations as crowded. This chapter is concerned with the application of multidimensional scaling techniques to the area of subjective crowding and, in particular, it focuses on the relationship between perceptions of similarity and preferential choice among crowded situations.