Oversized Area Indications on Bonus Packs Fail to Affect Consumers’ Transactional Decisions—More Experimental Evidence on the Mars Case

Findings from behavioural research are gaining increased interest in EU legislation, specifically in the area of unfair commercial practices. Prior research on the Mars case (Purnhagen and van Herpen 2017) has left open whether empirical evidence can provide an indication that this practice of using oversized indications of additional volume alters the transactional decision of consumers. This, however, is required to determine the “misleadingness” of such a practice in the legal sense as stipulated by the Unfair Commercial Practices Directive 2005/29/EC. The current paper closes this gap by illustrating how behavioural research can inform legal interpretation. In particular, it extends the previous research in two important ways: first, by examining the actual choice that people make; and second, by investigating whether the effects remain present in a context where a comparison product is available. Yet, while supporting and extending the findings of the study from Purnhagen and van Herpen (2017) on deceptiveness, the current study could not produce empirical evidence of a clear influence on the transactional decision of consumers, in the way “UCPD” requires.