Inducing perceptual super-items on shelf: results from an eye-tracking experiment

This study focuses on certain aspects of relative numerosity perception of item sets placed in side-by-side displays. Previous studies have demonstrated that, ceteris paribus, the perceived numerosity of item sets decreases as the amount of additional information (in terms of polygonal shapes) placed in the panel behind the displays increases. This result is attributed to a non-spatial type of clustering phenomenon exerted by the additional information. Unfortunately, however, the available literature does not address the perceptual mechanisms underlying the aforementioned effect. Our research is based on a laboratory study involving 200 participants. Using eye-tracking technology, we highlighted that upon augmenting the amount of additional information available in the decision-making context: (a) there was a significant decrease in number of total fixations per display; (b) there was an underestimation effect with regard to perceived numerosity of item sets involved. In light of the available literature, we interpret these findings as evidence that strategically placed additional information generates complex objects (termed super-items), which tend to perceptually substitute entire item sets. Super-items appear to serve as mediators to facilitate cognitive processes elicited by approximate numeration tasks concerning item sets being compared. Our study presents some managerial implications in terms of merchandising and category management.