Many researchers have identified a clear process by which consumers retain and retrieve brands during the pre-purchase process. Sheth proposed that all consumers had ‘Sets’ of brands.
His model shows that while we may be aware of many brands we only recall a few – the evoked set. Researchers can carry out prompted recall to identify which brands we are aware of but will not form part of the evoked set.
Of those brands that we recall only a few will form part of the consideration set from which a purchase is actually made.
For example we are all aware of the leading prestige brands – IBM, Rolls Royce, Thorntons etc.. but even if these are evoked in the purchase situation – they will not be part of our consideration set.
Reference: Joeseph W. Alba and Amitava Chattopadhyay, “Effects of Context and Part-Catagory Cues on Recall of Competing Brands, “Journal of Marketing Research” 22 (August 1985), 340- 349