Brand gravity®: why line extensions of national brands attract one another and line extensions of store brands repel one another : a thesis submitted in fulfilment of the requirements for the award of the degree of Doctor of Philosophy from Macquarie University

Brand gravity refers to the number of distinct product-relevant associations evoked by its exposure to the brand. The phrase 'distinct product-relevant associations' is an important aspect of brand gravity. In order to contribute to a brand's gravity, the associations that come to mind must be relevant for comparing and selecting alternatives from the specific product category in which that brand appears. Moreover, store brand (SB) associations are about the global retail brand (i.e., Coles or Woolworths), hence do not have gravity within any product category, whereas national brand (NB) associations are product category specific (e.g. Nescafe = coffee), and so create brand gravity. When two products have more shared than unique brand associations, they are perceived to be more similar when both are featured together compared to when they are evaluated separately. Conversely, when two alternatives have more unique than shared brand associations, they are perceived to be less similar when both are featured together compared to when they are evaluated separately. Due to differences in promotional budgets and product category breadth, NBs evoke more product-relevant associations than SBs (i.e. NBs have higher brand gravity than SBs). Hence, for SBs an efficient strategy for establishing multiple price points in a product category is to use different sub-brands under the same SB parent brand, because the multiple variants (i.e., line extensions) of the same SB "repel" one another to different price points. In other words, there is little or no attraction effect at the parent brand level, so the differences in the sub-brands produce a net repulsion effect. However, this tactic does not work for NBs. Since NBs evoke many product-relevant associations, multiple variants of the same NB "attract" one another to the same price point because they share so many associations at the parent brand level. Barring a substantial investment of time and money to create equity at the sub-brand level, the net effect of introducing multiple line extensions under the same NB will be attraction, hence it will be difficult to establish multiple price points in this way. Instead, it is necessary to introduce different parent NBs into the same product category to establish multiple price points.