How Do Consumers Compare BOGOF Promotions: Diagnosing Disruptions of the Rational Process
(A2025-125839)

AUTHORS

GILLES LAURENT, ESSEC Business School; raphaelle pandraud, ESCP EUROPE; MARC VANHUELE, HEC Paris; Madhav Arora, ESSEC Business School

ABSTRACT

We use eye-tracking to monitor the process used by consumers when they compare two competing Buy-One-Get-One-Free (BOGOF) promotions (e.g., 3 avocados for 7€ vs. 2 avocados for 5€). While consumers follow largely, as expected, the rational comparison process taught in elementary school (dividing, for each offer, the price by the quantity), they also make an important proportion of apparently counter-productive eye movements typical of the intuitive, error-prone, heuristic known as the “Whole Number Bias” (comparing the two prices against one another, or comparing the quantities against one another). This proportion provides a quantified diagnostic of the Whole Number Bias. Consumers also display “revolving attention,” moving their eyes back-and-forth many times across the two offers, instead of examining them one after the other. A better identification of the process helps understand which factors make the comparison more or less difficult, offering bases for policy recommendations.