Across countries and cultures, what people eat is influenced by social norms — those unwritten rules and expectations that guide behavior and tell us what’s “normal.” People generally eat what their family and friends eat, and don’t question these choices. Choosing a plant-based meal is something that still goes against established norms in many cultures.

One way to encourage behavior that goes against the prevailing social norm is to use dynamic norm messaging. In marketing, this involves informing consumers that there’s an ongoing shift in society, where people are increasingly choosing some alternative. Consumers are then prompted to take part in this shift.

The aim of the current study was to test the effectiveness of dynamic norm messages in influencing people to choose plant-based foods, both in an online simulated food order and in an actual retail food environment. These were tested against two other types of social norm messaging:

• Descriptive norms, which highlight what most people are already doing; and
• Injunctive norms, which emphasize what others approve or disapprove of.

Online Experiment

Participants were recruited to order food from a fast food restaurant in an online simulated experiment. They also completed a questionnaire designed to identify factors that might influence their order, including age, ethnicity, dietary preferences, and cultural values such as collectivism (a tendency to prioritize group harmony). Those who followed a vegan or vegetarian diet or rarely ate meat were excluded from the study. The final sample included 892 participants from Australia, China, the Netherlands, Portugal, Singapore, Taiwan, the U.K., and the United States.

Participants were randomly divided into four groups, three of which received either a descriptive, dynamic, or injunctive norm message on the restaurant menu. The remaining group served as the control and received a generic message unrelated to social norms. The outcome being tested was whether the participant chose a meat-based meal or a plant-based meal from the menu.

Results showed that both the dynamic and injunctive norm messages increased the likelihood of someone choosing a plant-based meal. For the dynamic norm message, this increase was almost 20%. The effect of the dynamic norm message was somewhat stronger than the injunctive norm message, though this difference may have been due to random variation. The descriptive norm message wasn’t found to be effective.

Interestingly, a greater sense of collectivism resulted in plant-based meals being chosen more often, regardless of social norm message. The fact that collectivism didn’t have a moderating effect on how the social norm messages were received suggests that they may be effective across different cultures.

Field Experiment

A retail burger outlet in Germany, comprising 44 stores, agreed to participate in the field experiment. Stores were randomly assigned to an experimental group and delivered a uniform social norm message (or a no-message control) to all of their customers who ordered from a self-service terminal. In addition, a neutral message, labelled as “standard,” was used at some stores. This time, the injunctive message wasn’t considered appropriate in the retail environment, so the experiment conditions were fourfold: descriptive, dynamic, standard, or control.

The intervention took place over two weeks. The outcome — the number of meat-based versus plant-based food purchases — was also monitored five weeks before and five weeks after the intervention.

Regardless of intervention, there were considerable differences among stores. Thus, store location was treated as a random effect in the statistical model, allowing the analysis to focus on the effect of the intervention while accounting for natural variation between stores.

Results showed that the dynamic norm message increased plant-based meal sales by about 8%, although the uncertainty in this estimate is reasonably high. Again, the descriptive norm message wasn’t found to be effective.

Stores that used a social norm message — either dynamic or descriptive — saw an increase in plant-based sales in the post-intervention period when the message was removed. This points to a potential spillover effect, especially among frequent customers, where repeated exposure to social norms may have encouraged longer-term plant-based food purchases. The experiment also revealed a background trend of rising plant-based consumption regardless of messaging and location.

For advocates, results from both the online simulated and real-world retail experiments suggest that dynamic norm messaging can be effective at shifting consumer behavior towards plant-based options. Because the intervention is low cost, low risk, and easy to implement at scale, this may be attractive to businesses looking to influence customers in a similar way. Advocates can check out this Faunalytics factsheet for specific advice on constructing dynamic norm messages.