Green Defaults and Environmental Information Increase the Probability of Choosing No Cutlery in a Randomized Survey Experiment in Hanoi Vietnam
A randomized survey experiment in Hanoi demonstrates that combining green defaults with environmental information significantly increases the likelihood of food-delivery customers choosing no cutlery, raising the rate from 23% to 83.3% by leveraging choice architecture and credible communication.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Every day, millions of people in cities like Hanoi order meals through smartphone applications. The process is quick and familiar: select a dish, choose a delivery time, and tap to pay. Yet, at the very end of this routine, a small decision often happens without much thought. The app asks whether the customer wants a set of disposable plastic cutlery included with the food. For many, the answer is automatic. They accept the pre-selected option, or they do not notice the choice at all, simply because they are focused on the meal or the price. This small habit, repeated thousands of times a day, generates a massive amount of plastic waste that is used for only a few minutes before being thrown away.
The question researchers asked was not whether people care about the environment, but whether the design of the screen itself could help them act on that care. In the field of behavioral science, the way choices are presented is known as "choice architecture." A powerful tool within this field is the "default." A default is simply the option that happens if a person does nothing. If a box is already checked, most people leave it checked because changing it requires a tiny bit of extra effort. Another tool is providing clear information that explains why a choice matters. While people often say they want to help the planet, they frequently fail to do so when the path of least resistance leads to waste. This study explores how combining a smart default with a simple message might change that behavior in the real world of food delivery.
To test this, researchers in Hanoi, Vietnam, set up a controlled experiment involving 243 adult users of food-delivery apps. They did not ask people what they would do in the future; instead, they asked them to make a real choice on a simulated checkout screen. The participants were randomly divided into four groups, each seeing a slightly different version of the final order page. One group saw the standard screen where the option to include cutlery was already selected, and no special message appeared. A second group saw the same screen, but the option to decline cutlery was pre-selected instead. A third group saw the standard screen with a cutlery option selected, but a short message appeared explaining that choosing no cutlery helps reduce waste. The fourth group saw the most powerful combination: the "no cutlery" option was pre-selected, and the environmental message was displayed right next to it.
The results showed a clear and dramatic difference in behavior. In the standard group, where cutlery was pre-selected and no message was shown, only about 23 percent of people chose to decline the plastic utensils. When researchers simply changed the default so that "no cutlery" was the pre-selected option, the number of people declining the utensils nearly doubled to about 46 percent. When they showed the environmental message alone, without changing the default, the rate rose to about 39 percent. However, the most striking result came from the group that received both the green default and the message. In this combined condition, 83 percent of participants chose to decline the disposable cutlery.
The study found that these two tools worked better together than apart. The default made the sustainable choice the easiest path, requiring almost no effort to follow. The message provided a reason, making the choice feel meaningful rather than arbitrary. When both were present, they reinforced each other, creating a situation where the environmentally friendly action was both effortless and clearly justified. The researchers also looked at the people behind the choices. They found that individuals who already cared deeply about the environment were more likely to choose the green option, but even those with strong environmental concerns benefited from the helpful screen design. Conversely, people who had a strong habit of always using the plastic cutlery provided with their orders were less likely to change their behavior, highlighting how difficult it can be to break a routine even when a person wants to.
This experiment suggests that the solution to the plastic waste problem in food delivery does not require complex technology or expensive incentives. It requires a simple shift in how the choice is presented. By making the sustainable option the standard one and explaining why it matters, platforms can guide millions of users toward better choices without taking away their freedom to decide. The study confirms that while habits and convenience often drive our daily actions, a well-designed interface can gently nudge those actions in a more sustainable direction, turning a routine click into a meaningful act of environmental care.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.