Prior research has assumed that existing knowledge exerts its influence on consumer judgments primarily through abstract knowledge structures. Consequently, little attention has been given to the possibility that judgments may, under certain circumstances, be influenced by knowledge associated with more specific knowledge structures. This article examines the factors responsible for determining the impact of abstract versus specific knowledge on consumer judgments. Based on the Consumer Learning by Analogy model (CLA model; Gregan-Paxton & John, 1997), it is argued that the relative influence of abstract and specific knowledge is a function of (a) the relation between the new product and existing knowledge and (b) the nature of consumer's knowledge. These ideas were tested in a series of experiments in which participants were required to judge a new product that varied in its relation to an existing product or brand. In this context, the influence of specific knowledge was most evident when participants were able to construct an attribute mapping, but not a relational mapping, to link the novel product to a familiar brand exemplar. When it was possible to construct a relational mapping, a more abstract knowledge structure, such as a schema, was retrieved and used as the basis of product judgments.