Paying for no reason? (Mis-)perceptions of product attributes in separate vs. joint product evaluation

Consumer decision-making involves the evaluation of options either in isolation or in relation to other alternatives present at the environment. According to Hsee's evaluability hypothesis, it is easier to evaluate product attributes when they are juxtaposed (i.e., presented jointly) than when they are presented in isolation from each other. Recent research has provided some support to the evaluability hypothesis for the attribute of perceived product quantity. The present research tests the hypothesis in relation to the attribute of perceived fairness. In two experiments, we show that when participants evaluate products in isolation from each other, they err in their judgment of product quantity, and, consequently, they mis-attribute fairness to the seller. In a third experiment, we further show that the inclusion of constant yet unfair price information does not affect the fairness and price judgments. These findings provide evidence for the psychological plausibility of the evaluability hypothesis for the attributes of fairness and product quantity. Moreover, they suggest that isolated product evaluation may be systematically suboptimal for consumers, even when pricing information is included. Therefore, effective consumer decision-making will benefit by allowing the joint evaluation of alternatives.