A nudge that did not work: a virtual supermarket study among children to promote healthier snacking

Nudging consumers towards healthier food choices is still a hot topic. Drawing on psychology and behavioural economics, nudges are simple intervention strategies to move consumers towards healthier choices. This is done without banning foods products or telling consumers what to eat or avoid.

There are quite a few examples of successful nudges that help consumers in making better food choices. For instance, if consumers were asked to downsize their side dish, they ended up eating less in the study of Schwartz and colleagues. Still, there is a lot of debate about the usefulness of nudging. Consumers need more than a nudge, is the argument put forward by Lucy Handley. Lord Krebs recently argued in the Guardian that nudging alone will not convince people to do important things like lose weight. They both might be right, but at the same time I think it very useful to collect empirical evidence on the effectiveness of nudging.

Last Summer, we carried out a nudge study among 113 primary school children (10-12 years old) to encourage them to go for a healthier snack. We were inspired by the proven marketing tactic to offer a free gift with purchase (think of McDonald's Happy Meal). Typically, children are confronted with these free gifts on energy dense snacks. But would it be effective to use this classic marketing tactic to encourage children to switch to something healthier? That was the key question in our virtual supermarket study on which Charlotte Petri graduated last August.

We asked children to do some groceries in the virtual supermarket and select their own snack and drink near the checkout counter. This simulated supermarket of Wageningen University looks like a real supermarket with various shelves which display three-dimensional images of a wide range of products. The children could walk through the aisles of the store and put products in their virtual shopping cart.

Participant chooses a snack in the virtual supermarket

Participants did not see the same snack shelf, however. One third of all participants were confronted with a shelf poster that promised them a free gift (a tattoo) when they would buy a product with a star. These 'star products' were all healthier options as indicated by the Dutch Nutrition Centre. Another group were similarly promised the same gift, but now the star was attached to relative unhealthy snacks. The third group was the control group who did not get to see any promise of a free gift.

Snack shelf with poster promising free tatto gift with healthy 'Star' purchase

Most children were very enthusiastic about 'shopping' in the virtual supermarket ('Where can I download this game?'). Less than half of all children selected a healthy snack and drink. They were, however, not influenced by the promised free gift, regardless of the type of product to which the star was attached. It could be that the gift was not attractive enough, although a pre-test indicated differently. Another explanation is that children might have been too focused on the shopping task. In other words, they were too 'busy 'walking' through the shop, impressed by the new experience.

About one fifth of all participants was overweight. This percentage is similar to the percentage Dutch children who is overweight. Although overweight children more often tended to go for unhealthy snacks, they were not more sensitive to the free gift than normal-weight children. Children chose snacks based on familiarity and preference. Health was less important in their choice.

Overall, although the nudge was not effective in its present form, we learned a lot about the possibilities of the virtual supermarket for choice experiments with children. Have a look at the video, in which a participant walks through the supermarket and makes her snack choice.