The difference between differences: How expertise affects diagnosticity of attribute alignability

Whereas past research showed that people rely more on alignable than nonalignable differences when evaluating alternative products, the current article shows that consumer expertise moderates this effect and that novices' reliance on alignable attributes can be attenuated when they are motivated or are provided with category knowledge. The authors conducted four experiments to test their hypotheses. Participants considered nonalignable (vs. alignable) attributes to be more differentiating between two competing brands, especially among experts (study 1). In addition, compared to novices, experts more actively sought out nonalignable attributes (study 2) and relied more on nonalignable than alignable attributes when making brand choice decisions (studies 3 and 4). Consistent with the hypothesis that experts' processing of nonalignable attributes is driven by their deeper motivation and knowledge, enhancing motivation (study 3) and the knowledge base (study 4) among novices led to their increased use of a nonalignable attribute as the basis of judgment.