For the love of bread: Sometimes a nudge is not enough

Many people know that the placement of products at supermarket shelves is done in such a way that consumers spend more money on the most profitable items. The products you are most likely to purchase are at eye level or at the end of aisle display. These ‘psychological tricks’ are explained in popular magazines (see ‘15 sneaky ways supermarket get you to spend more’), and many studies provided robust evidence on how strong consumers are influenced by the environment in which they shop, eat and drink. It is hard to resist the temptation of unhealthy foods in these environments, particularly when we are rushed or tired.

Nudging builds on the idea that if we better understand how consumers actually make decisions, we can use these insights to boost sales and consumption of healthy foods. Nudging is, however, not a marketing ‘trick’ in that its primary aim is to increase revenues. Rather, the aim is to encourage more beneficial decisions from a consumers’ perspective, such as eating healthier or sustainable. Nudges are simple, inexpensive interventions that support consumers in making these choices without banning products (you are free to grab the unhealthy snack) or telling them what to do.

In a recent paper (first authored by René de Wijk), we report a nudging experiment conducted in two supermarkets in The Netherlands. Our nudge was targeted at whole wheat bread, as many people worldwide do not eat enough whole grain products. In both supermarkets, the fresh bread department was located next to the entrance. In the ‘healthier bread first’ situation, whole wheat bread was placed at the entrance of the aisle for several weeks. This made the bread more prominent and accessible. In the ‘healthier bread last’ situation, the order was exactly the opposite: consumers were first exposed to white bread and whole wheat bread was put at the end of the shelf area. Results of our study showed that about one third of all bread sales consisted of whole wheat. Unfortunately, this proportion did not change due to our manipulation. In other words, a more convenient and accessible shelf position for whole wheat bread did not increase sales.

Although our nudge did not shift purchases towards healthier whole wheat bread, this does not mean that nudging is useless. One can think of several reasons why nudging did not work in this context. Perhaps there is a small effect of our nudge that we could only have captured if we had measured sales for longer time periods and in more supermarkets. After all, even small changes can make a difference when they all add up. The difference between white and whole wheat might also have been too large. Moreover, bread is typically purchased on a regular basis, sometimes even daily. It is a type of food that consumers purchase without much reflection. A perfect target for nudging, you might think, as the nudging approach assumes to engage with the automatic and intuitive thinking modes of people. Nevertheless, it seems that consumers are quite loyal to their favourite type of bread.

No single nudge will lead to healthier eating patterns. Perhaps we need to load the entire supermarket with nudges or combine them with other interventions to get the changes in consumer behaviour we are looking for. More importantly, assessing the effectiveness of nudging interventions can only happen if we publish both effective and ineffective nudges. Many scientists are familiar with the publication bias that exists in that mainly positive results are published in prestigious scientific journals and get headlines in the media. The practice of leaving negative results in the infamous ‘file drawer’ leads to disappointing replication efforts and distorted meta-analyses and systematic reviews. Our study hopefully contributes to a better understanding of which nudges work and which not in realistic field situations.

The full-paper can be read without subscription at Plos One: An in-store experiment on the effect of accessibility on sales of wholegrain and white bread in supermarkets, and is authored by René de Wijk, Anna Maaskant, Ilse Polet, Nancy Holthuysen, Ellen van Kleef and Monique Vingerhoeds. For more studies on nudging, see the project page.

Ellen van Kleef

About Ellen van Kleef

Ellen van Kleef studies overeating, self-control and healthy food consumption interventions. She focuses on the role of subtle cues in the environment that cause people to overindulge and on how changes in the environment (smart interventions) can assist in self-control. She published her research in international journals such as Journal of Health Psychology, Food Quality and Preference, Appetite, Psychology and Health and Public Health Nutrition.

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