Wardle, J., Herrera, M.L., Cooke, L., Gibson, E.L. (2003) European Journal of Clinical Nutrition 57(2) 341-8.
OBJECTIVE: The aim of this study was to evaluate two interventions (one reward-based and one exposure-based) for increasing children's acceptance of an unfamiliar vegetable compared with a no-treatment control. It was predicted that the exposure condition would increase liking for, and consumption of, the vegetable relative to either the reward or control group.
DESIGN: Using a randomized controlled design, participants were assigned to one of two intervention groups (exposure or reward) or to a no-treatment control condition, for a 2 week period. Liking for, and consumption of, red pepper was assessed before and after the treatment period.
SETTING: The study was conducted in three primary schools in London.
SUBJECTS: Parental consent was obtained for 49 out of a possible 72 children.
INTERVENTIONS: Interventions comprised eight daily sessions during which participants in the exposure group were offered a taste of sweet red pepper and told that they could eat as much as they liked. Participants in the reward group were shown a sheet of cartoon stickers and told that they could choose one of them on condition that they ate at least one piece of the pepper.
RESULTS: The exposure-based intervention significantly increased both liking (P=0.006) and consumption (P=0.03) compared with the control group. The outcome of the reward intervention was intermediate and did not differ significantly from the exposure or control conditions.
CONCLUSIONS: Repeated exposure to the taste of unfamiliar foods is a promising strategy for promoting liking of previously rejected foods in children.
In this study, two different approaches were used to try to increase children's acceptance of an unfamiliar vegetable (sweet red pepper). A total of 49 primary school children were randomly allocated to one of three groups, and their liking for, and consumption of, sweet red peppers was assessed before and after the 2-week study period.
Children in two of the groups took part in 8 food-tasting sessions at school on different days over the 2-week period. The third group of children were not involved in these sessions, but were included as a control group for comparison.
Children in one of the treatment groups were invited simply to taste the vegetable, and told that they could eat as much as they liked (the 'exposure' condition). Children in the other treatment group were offered the chance to choose a cartoon sticker if they ate at least one piece of red pepper (the 'reward' condition).
Compared with the control group, children in the simple 'exposure' condition showed a significant increase in both their liking for, and their consumption of, sweet red peppers over the study period. Preferences of children from the 'reward' group increased slightly, but they didn't differ significantly from either the control group or the children who were simply given repeated exposure to the vegetable.
The researchers concluded that repeated exposure to the taste of unfamiliar foods (without any pressure or reward) is a promising strategy for encouraging children to develop a liking for new foods they might previously have rejected.
The apparent aversion that many children have to vegetables is well-known, as is children's general reluctance to try new or unfamiliar foods (this is known as 'neophobia'). This simple, elegant and well-controlled study showed that simply offering children repeated opportunities to taste an unfamiliar vegetable increased their preferences for it. By contrast, offering rewards didn't work, although this is understandable (if you have to be bribed to eat something, it can't be very nice, can it?) These findings are very important for anyone trying to improve children's dietary choices by getting them to try unfamiliar foods.