Size Does Not Matter: Numeracy and the Effect of Quantity Information on Consumers' Price Judgments

Abstract

A product's printed quantity information (e.g., 12 oz) is thought to provide meaningful information for product evaluations. However, previous research suggests that consumers often do not weigh this information. It remains unclear whether some people, in fact, do weigh the information and what factors (e.g., package design) might increase or decrease such a consideration. In one lab experiment and one eye-tracking experiment, we examined the influence of individual differences in objective numeric abilities on the perception and use of quantity information. In both experiments, participants indicated willingness-to-pay judgments for consumer goods (e.g., chocolate and cereals) that varied in their quantity (e.g., 100 vs. 200 g). In each case, we observed an interaction between objective numeracy and quantity on willingness-to-pay judgments. More numerate individuals were more likely to look at quantity information and to use this information in their willingness-to-pay judgments, whereas people with lower numeracy often did not differentiate between quantities. Variations in package design did not change this effect, but the presence of additional quantity indicators increased the use of the original quantity information for people who were more and less numerate. Implications for consumer protection are discussed.