Why Adding Green Doesn’t Add Up: A Multicategory Investigation of the Negative Footprint Illusion
(A2026-134043)

AUTHORS

Karen Gorissen, BI Norwegian Business School; Bert Weijters, Ghent University

ABSTRACT

Consumers often misjudge the environmental impact of product bundles. When an environmentally certified option is added to a set of conventional products, many people perceive the total footprint as smaller, a biased called the Negative Footprint Illusion (NFI). We examine whether this illusion depends on the product domain or reflects a general psychological tendency. Using footprint judgments for 15 distinct product categories, we find that responses are driven by a single latent NFI factor with only minor category level deviations. A latent class analysis reveals two distinct consumer types; one consistently shows the illusion, while the other does not (high on compensatory green beliefs, environmental concern and education). These results demonstrate that the NFI is a domain general judgment bias that combines continuous and categorical variation. This clarifies who is most vulnerable and why eco information can at times lead to biased judgments.