The Effect of Similarity Between a Product¡¯s Shape Properties and the Benefit Offered on Judgments and Preferences

Studies show a product's shape affects consumer judgments. Yet, the basic principle that governs shape effects is unclear. In this study, we fill this gap by demonstrating that causal-reasoning considerations govern shape effects. Specifically, people expect cause (e.g., an energy drink) and its effect (e.g., fat burning) to exhibit some degree of resemblance or congruency (¡°like causes like¡±). This expectation leads them to use the ¡°law of similarity¡± heuristic when judging artifacts. In two studies, we focused on a product's shape. For half of the products, the shape was an intrinsic property of the product (i.e., had the causal power to produce the effect), and for the other half, the shape was an extrinsic property of the product. For both kinds of properties (extrinsic and intrinsic), we demonstrate that the same ad (e.g., an energy drink that "claims" to produce fat burning) is more persuasive (willingness to purchase the product, and choice between products) when the product's shape is congruent rather than incongruent (e.g., a ¡°tall¡± can vs. a ¡°short¡± can) with the effect promised. We strengthen the notion that leaning on a cause-effect-similarity heuristic is very basic, by showing that choice situations accelerate the effect of congruency more for products for which the focal property is extrinsic than for products for which it is intrinsic. In line with other studies that show causal reasoning considerations govern judgment and choice on artifacts (products), the present study demonstrates causal-reasoning considerations govern judgment and choice concerning the cause-effect-similarity heuristic as well.