Zeithaml (1988) and Steenkamp (1997) classify the concept of perceived quality in two groups of
factors that are intrinsic attributes and extrinsic attributes. The intrinsic attributes are related to the
physical aspects of a product (e.g. colour, flavour, form and appearance); on the other hand, extrinsic
attributes are related to the product, but not in the physical part of this one (e.g. brand name, stamp of
quality, price, store, packaging and production information (Bernue´s et al.2003). It’s difficult to
generalize attributes as they are specific to product categories (Olson and Jacoby 1972, Anselmsson et al. 2007)