has been shown to be important in the reciprocal transfer of affect from the extension back to the original brand (Loken and John 1993), and to play a role in sequential extensions (Keller and Aaker 1992).Yet there are reasons to suspect that we do not fully understand the interaction between the brand name and the product category in the determination of similarity judgments. Previous studies in brand extension have taken several different perspectives with respect to the relationship between brand name and product category. In some studies, the brand name is fictitious and plays little or no role in brand evaluations or the implicit similarity judgments posited to drive them (e.g., Boush and Loken 1991; Keller and Aaker 1992). In others, brand and product categories are considered separately. Park et al. (1991), for example, consider similarity (concept consistency) between the brand concept separately from the product category. A third category of research studies views the brand name and the product category as interacting to produce similarity judgments. For example, Schmitt and Dube (1992) demonstrated that a brand name (McDonald’s) can act as a modifier for a new product category (theme parks) to create original conceptual combinations not before associated with either the brand or the product (rides shaped like golden arches). Broniarczyk and Alba (1994) focused on how distinctive brand associations such as decay prevention for Crest toothpaste or breath-freshening for Close-Up affected brand extension evaluations. They demonstrated that in some cases brand-specific associations are more important than either the similarity between product categories or the affect toward the brand. However, no research to date has examined the way brand names influence perception of similarity between product categories.
The current study will attempt to extend previous work by looking for regularities in interproduct similarity judgments, arguing that one way to look at extension of a brand name into multiple product categories is that the association of a brand name with a new product category can create and reorganize structures of consumer knowledge. Further,one way to better understand the reorganization of consumer knowledge that takes place when a brand extends to a new category is to look at the effect that the brand name has on the structure of interproduct similarity relationships. Therefore we will examine aspects of similarity as revealed by comparing judgments of similarity between products with and without a brand name.We will be particularly interested in the directional nature of similarity perceptions. In order to address these issues we first need to review some basic notions surrounding similarity.