Part-Worth Utilities of Gestalt Principles for Product Esthetics: A Case Study of a Bottle Silhouette

Abstract

Reaching a balance between product form and function is one of the main challenges of design teams. When users make choices among products with similar functionality and price, esthetics becomes a decisive factor, and understanding how they are perceived through the product form can allow designers to create new designs with more appealing shapes. Gestalt principles explain how subjects group elements of a shape and devise them as a whole, and recent research has proposed their quantification for evaluation of esthetics. This work examines a previous methodology to quantify Gestalt principles of 2D product representations, in particular, expressions to measure the principles of symmetry, parallelism, and continuity are applied to parameterized forms, with a generic bottle silhouette as case study. First, the representation is divided into key atomistic elements, which are generated through cubic Bézier curves. Then, the quantifications of symmetry, parallelism, and continuity, in conjunction with gradient-based optimization, are used on these forms to generate bottle silhouettes with combinations of high and low levels of each principle. The resulting designs were submitted to a discrete choice study in which respondents selected the bottle silhouettes they found more appealing. The preference data were analyzed with both fixed and random coefficients multinomial logistic regression (mixed logit) to determine the part-worth utility of each Gestalt principle over esthetic preferences. In conclusion, the results show differences in the utility estimates of symmetry, parallelism, and continuity, and implications for designers are discussed.