Changing Eating Habits: A Field Experiment in Primary Schools

We conduct a field experiment in 31 primary schools in England to test whether
temporary incentives are effective in increasing children’s choice and consumption of fruit and vegetables. The intervention consists of rewarding children with stickers and little gifts for a period of four weeks for choosing a portion of fruit or vegetables at lunch. We compare the effects of two incentive schemes (piece rate and competition) on choice and consumption over the course of the intervention. We also examine the effect of the interventions immediately after the incentives are removed and six months later to see if the temporary incentives had any lasting effect on dietary choices. We find that the two interventions, in general, had positive effects on choice and consumption and that the competition works better overall. However, we find that the treatment effects vary dramatically by age, gender and socio-economic background. We find little evidence of sustained long term effects, except for children from poorer socio-economic backgrounds.