5 Mins Read
By Sophie Attwood, Sebastian Isbanner and David Fechner
New research: targeted messaging can encourage both plant-based and meat eaters to select more plant-based meals on online food ordering platforms.
One of the first facts drilled into all students of human behavior is the power of past behavior to predict our future actions. Despite our desire to see ourselves as agents of free choice, much of what we do is habitual and, as a result, highly predictable.
While this insight may feel fatalistic, it’s incredibly useful for behavioral psychologists, whose job is to influence others’ actions. Like ripples in a pond, if we can influence a person’s habits in one area of their lives – be it their diet, finances, or work – there’s a strong probability that this shift will spill over into related behaviors.
This carry-over effect is vital because making a one-off change is rarely enough to achieve concrete progress toward the goals we care about most. Like many of our good intentions – losing weight, saving money, or managing excess workload – all require consistent, directed effort over time and across contexts.
Going in circles
Substantial research has already explored how spillover effects modify peoples’ pro-environmental behavior. For example, researchers have studied whether encouraging people to recycle their cans or avoid plastic bags will eventually transfer to more important decisions, like driving less, taking fewer flights, or reducing ruminant meat consumption. The hope here is that inducing smaller shifts in behavior might act as gateways to larger, more impactful changes.
Yet, with sustainable food choices in particular, there are some lingering concerns that compensation behaviors might kick in before this positive transfer can happen. A salad at lunch could leave you feeling deprived and craving a bigger burger at dinner time. Given that the ‘big picture’ for most sustainable diet change is to create an overall reduction – in either carbon emissions, damage to biodiversity, or excess water or land use – compensatory behaviors must be prevented so they don’t cancel out any initial hard-won gains.
Reinforcing good behavior
So, what’s to be done? How can we ensure behavioral spillover works in our favor, and, more importantly – how do we intercept that past-behavior-future-behavior loop in the first place? These were two questions that we recently explored in a study of people’s food choices when ordering online, with the goal of seeing if we could leverage past food ordering tendencies to promote more environmentally friendly meal choices in the future.
We asked our study participants, which excluded vegans and vegetarians, to enter an online food delivery platform and order meal kits for the coming week and select their preferred lunch and dinner. While our ‘control’ group received a generic message about the success of online meal delivery services, our ‘intervention’ group received a short pop-up message just after selecting their daily lunch, which encouraged them to opt for a tasty plant-based dinner and read as follows:
Did you know that by opting for a plant-based dish, you could save greenhouse gas emissions equal to the energy needed to power your phone for two years? Choosing plant-based reflects a commitment to a more environmentally friendly lifestyle. |
We were interested in how this short paragraph might influence our participants differently depending on whether their original lunch choice – i.e. their past behavior – was meat-based or plant-based. Published in the Appetite journal, our results for those who initially selected a plant-based lunch were as expected. The pop-up message led to a 51% increase in the number of plant-based dinners subsequently ordered.
When we explored exactly how this short message was working, our data showed that it reinforced our plant-based lunch choosers’ self-identity. The pop-up highlighted how their actions aligned with their desired sense of self as an ‘environmentally friendly’ (i.e. ‘morally good’) person.
Dealing with dissonance
Perhaps more interesting, however, was the impact of our message on the meat-based lunch eaters. For those who originally preferred chicken or beef, we were interested in whether these past preferences would carry through to dinner or whether our message would influence choices in a different direction.
Our data showed that we can, to some extent, untether people’s future choices from their past habits. While those who opted for a meat-based lunch still selected more meat dinners (their preferences were consistent over time), our pop-up led to a significant increase in the number who switched to a plant-based dinner instead.
The message still seemed to influence participants’ self-identity, but this time in a slightly different way. Rather than providing a flattering mirror to their ‘good’ past behavior, the message emphasized the discrepancy between our meat-based lunch choosers’ current actions and the positive identity described in the message – of being someone committed to helping the environment.
Becoming aware of this gap between actual behavior and perceived self-image as a morally good person induced a sense of cognitive dissonance – a feeling of mental discomfort – that was sufficiently strong to motivate a 27% swing away from meat. With the US meal kit sector generating around US$5.65bn in 2024, a weekly shift of this magnitude is no small deal.
Future you is a click away
As with all other behaviors, our past actions matter when it comes to food. People who are open to choosing plant-based meals can be encouraged to maintain and extend this habit simply by highlighting their existing positive actions and reinforcing these with a short, flattering message.
Yet, as our study shows, our future choices are also not inevitabilities. Meat eaters can still be encouraged to select meat-free options if we push the right influence buttons. Our data shows that a message reinforcing a desired self-identity can play a valuable role, especially in the context of online food ordering platforms where changing our behavior to align to a desired, positive self-image is just a button click away.
No coercion or criticism is needed; just a short reminder that you can become the type of person you want to be.