Before the lunch line: Effectiveness of behavioral economic interventions for pre-commitment on elementary school children's food choices

In this study, we intervened in elementary schools on lunch entrée selection using some of the behavioral economic methods shown to be effective in earlier food choice studies. Unlike many earlier behavioral interventions, which were mostly done in controlled environments and smaller café type settings for one-off interactions, we conducted our interventions in a real-world environment in twelve elementary schools in one school district in South Carolina over nine school weeks. By increasing salience and prominence of the healthy entrée of the day through visual and verbal tools, we nudged students towards selecting healthier options in treatment schools. We estimated the treatment effects using a difference-in-differences setup, comparing changes in the share of students selecting nudged entrées during the treatment period relative to the shares before the treatment period in treatment and comparison schools. Our estimates show that the nudges are effective when present. They increase selection of the healthy option by thirteen to thirty-five percent on the days the entrée is treated. Effects disappear when the nudge is removed, however, and there is evidence for reduced effectiveness of nudges in repeat instances. There is no evidence of habit formation.