Researchers encouraged kids to eat more carrots and green beans with pictures. They merely put photos of the veggies on the kids school trays as they picked them up in line. Compared to a control day, merely putting a picture on the tray encouraged more veggie taking and consumption.
The intervention was associated with an increase in the percentage of students taking green beans from 6.3% (42/666) to 14.8% (96/647) (Table; z = 5.04, P < .001), and the percentage of students taking carrots from 11.6% (77/666) to 36.8% (238/647) (z = 10.70, P < .001). The amount of green beans eaten by students who took them did not differ between the control day (mean of 19.0 g) and the intervention day (mean of 19.1 g; t136 = 0.08, P = .93). Overall, the intervention was associated with a significant increase in the amount of green beans consumed per student exposed (from mean of 1.2 g to 2.8 g; t1311 = 38.00, P < .001). The amount of carrots eaten by students who took them was significantly higher on the control day (mean of 31.0 g) than the intervention day (mean of 27.1 g; t313 = 5.28, P < .001), and the intervention was associated with a significant increase in the carrot consumption overall per exposed student (from mean of 3.6 g to 10.0 g; t1311 = 87.18, P < .001).
The Windowpanes for the percentage of kids taking veggies are Small+ and Medium+ while the consumption Windowpanes are Small. They are entirely consistent with effect sizes from Low WATT Cues, so this is right in the middle of the research literature for these kind of persuasion plays.
The authors suggest that these Ding Dongers function as normative cues, “. . . indicate to the children that others typically select and place vegetables in those compartments and that they should do so too,” which is exactly the Comparison Cue (If Others Are Doing It, You Should, Too.) I’m dubious of that and there’s nothing in this simple design to support it. The photos as described in the report only show a picture of the veggies and don’t show a picture of a kid taking veggies. The absence of people in the photo clearly knocks out any social element. I’d argue that as described these photos are simple Ding Dongers, a Stimulus (the photo) that triggers a learned response (put veggies on your tray).
Past that quibbling, the authors correctly note that their effect sizes compare favorably to interventions that require those baroque public health dramas with special curricula, intense training of teachers, administrators, and food service personnel, bright posters, and Big Brother announcements over the PA system. This Ding Donger costs next to nothing and takes all the skill needed to put napkins in a dispenser. I’m sure the CDC will ignore this.
Sure, it’s only one school and one intervention day with one control day. Sure, it wouldn’t work if you did it every day the same way. But, if you did this in your school cafeteria three times a month and then some other Ding Donger or Cue a different three times a month, you’d get a Small+ increase in veggie consumption with almost no intervention cost. And, if you did it right you might build a new habit or strengthen an existing one that would persist past the Cue presentation.
Or you could get a $1.2 million grant and obtain the same effect! Maybe you could get Jamie Oliver the Celebrity Chef, too! That would feel better than these Ding Dongers!
Reicks M, Redden JP, Mann T, Mykerezi E, Vickers Z. Photographs in Lunch Tray Compartments and Vegetable Consumption Among Children in Elementary School Cafeterias. JAMA. 2012 Feb 1. Published online February 1, 2012.