How to Allocate White Space in Ad Design? The Impact of Product Layouts on Perceived Entitativity and Advertising Performance

White space (empty space) is an important factor in visual ad design, yet few studies focus on the specific types of white space and their influence on ad design. In this research, we systematically review white space literature; identify two types of white space, termed interspace (space in between a product layout) and circumspace (space surrounding a product layout); and investigate their effects on product layout perceptions. In four studies, we propose a not yet widely adopted practice: When holding the total white space constant, a lower interspace/circumspace ratio (more compressed product layout), compared with a higher interspace/circumspace ratio (less compressed product layout), can increase the perceived entitativity (i.e., perception of a unit as a group) of a collection of products in an ad and, ultimately, ad evaluation, purchase intentions, and click-through rates (CTRs). We further rule out potential alternative explanations and identify a theoretically and practically relevant boundary condition: If the products are framed as conceptually dissimilar, the perception of entitativity becomes less important, which reduces ad performance. We conclude by discussing the theoretical and practical implications of our research.