RETRACTED: Priming the Concept of Fullness with Visual Sequences Reduces Portion Size Choice in Online Food Ordering

Body mass indices and obesity rates are increasing worldwide, and one way to reduce caloric intake is to reduce portion size choice. In this research, the authors develop a behavioral intervention aimed at reducing portion size choices in the context of online food ordering. In eight experiments (including a field experiment), the authors show that the sequential presentation of two food images that move from partial to whole reduces hunger perceptions and portion size choices relative to all comparable sequences. This effect occurs because the partial-to-whole image presentation primes the concept of reaching fullness, which in turn reduces perceptions of hunger and portion size choices. The effect of image sequence on both hunger perceptions and portion size choices is mediated by the accessibility of the concept "full" and is attenuated when visualization of the dynamic sequence (partial-to-whole) is inhibited. The partial-to-whole sequence effect is observed even when the sequential images are unrelated to food, and it is robust across languages, age groups, food type, and choice contexts. This brief, low-cost intervention can be implemented across several online food-ordering contexts (e.g., school cafeteria apps, dieting apps) and has important public policy implications.