Tailoring through choice: comparing the effect of randomly assigned and self-selected behavioural interventions in promoting healthier snack choice

Abstract Public policy encourages healthier diets using interventions like financial incentives, calorie labelling or social-norm nudges. While evidence shows these interventions can influence behaviour, effects vary across individuals, indicating a need for tailored approaches. This study explores the effects of tailoring through choice, i.e., whether allowing individuals to choose interventions improves effectiveness. In a field experiment, 839 university students chose between healthier and less healthy snacks under three interventions: (i) small financial incentives, (ii) calorie information or (iii) a social-norm nudge (i.e., 60% chose healthily). Half the respondents were randomly assigned an intervention (or no-intervention control), while the rest selected and received their chosen intervention. Among respondents given a choice, 51%, 41% and 8% selected financial incentives, calorie labelling or social norms, respectively. Self-selected interventions (marginally) significantly increased healthy snack choices compared to the no-intervention control, while randomly assigned interventions did not. When accounting for individual characteristics, chosen calorie labelling and social norm nudges significantly increased healthy choices, while financial incentives did not. Allowing respondents to choose their intervention appears effective, while random assignment is not. This positive effect of choice may be driven by selection into calorie labelling and social norms, although respondent characteristics partially explain this effect.