The ability to form stable mental representations (or concepts) from a set of instances is fundamental to human visual cognition and is evident across the formation of prototypes, from simple pseudorandom dot patterns through to the recognition of faces. In this paper we argue that the cognitive and perceptual processes that lead to the formation of stable concepts are also important in understanding spectatorship of a certain class of serial artworks that are composed of multiple discrete but related pictures. This article considers the processes that enable the formation of stable mental representations in relation to a series of paintings of Rouen Cathedral by Claude Monet. The implications of understanding these processes for the spectatorship of this class of serial artworks are discussed.