Anya Samek, “Gifts and Goals: Behavioral Nudges to Improve Child Food Choice at School.” CESR-Schaeffer Working Paper Series, Paper No: 2016-007, January, 2016; available at SSRN.
• The author arranges for a field experiment to take place at eight public elementary schools in Chicago; the 1400 or so child subjects do not know that they are participating in an experiment.
• The only lunch menu choice that is available to these schoolkids every day is whether to get the (low-fat) white milk, the (low-fat) chocolate milk, or do without milk altogether. On the first day of the experiment, students are nonchalantly observed when they make their milk choices. Chocolate milk is the big favorite: more than 85% of kids take the chocy, 11% take white, and 3.4% go milkless.
• In the second and final day of the experiment, a control and two treatment goups are implemented. In the control condition, teachers very briefly explain the relative merits of white milk (chocy milk has added sugar, and that is less healthy, you see) shortly before lunch. In the “Gift” condition, the explanation is followed up by a gift of a sticker to all students, no questions asked and nothing required in return; and in the third condition, “Goal,” students are asked to make an unenforceable goal, a written pledge, as it were, to choose the white milk (though they can pledge themselves to chocolate).
• The control condition induces a huge increase in white milk purchasing, to over 47%. The Gift condition brings a slightly larger shift to white, with the Goal condition in between. The goal-setting “works” better for younger kids, but the sticker “works” about the same for everyone.
• The unconditional gift tries (and seemingly succeeds) to connect the milk choice to reciprocity; one advantage of an unconditional gift is that no enforcement (of conditions) is needed.
• The choices in the Goal group suggest a good deal of time inconsistency – lots of kids who pledge to get the white milk change their mind when the decision itself is at hand – even though the elapsed time between pledge and decision is only about 15 minutes.
• The fact that the nudge and its recorded effects are of the one-day-only variety is a pretty severe restriction on drawing policy advice from the experiment. My main takeaway, as it were, concerns the large shift towards choosing white milk in the control condition: a very short piece of pro-white-milk propaganda delivered by a teacher alters lots of elementary student milk choices. Use this power wisely!