What unsustainable behavior needs to change:

A key aspect of sustainable diets is to prevent overconsumption of unhealthy foods, which often carry a large environmental footprint. In this way, healthy and sustainable food choices can go hand-in-hand. 

However, food choices are difficult to change, because they often do not rely upon conscious reflection. Also, a large majority of food decisions are made in “busy” environments, such as (online) supermarkets, with multiple competing influences on food choice. Indeed, unhealthy food choices can be due to the lack of a clear and simple behavioural “trigger” for making responsible decisions at the right moment.

The Green Nudge:

A new type of digital nudge, called “just-in-time” (JIT) nudges, can positively influence product choice, such as when a person adds an unhealthy product to their virtual shopping cart. 

The Tilburg University researchers partnered up with industry mobile developer Nakko to carry out a large field experiment with more than 20,000 participants. The study tested the ability of digital JIT nudges to increase healthy food purchases using a mobile self-scanning app. With the app, people could self-scan product barcodes from supermarket shelves, which added them to a virtual cart for easier checkout. 

Participants in the study were divided into four groups. In the first group, when the app scanned an unhealthy product, it displayed a pop-up with a suggestion for a healthier alternative to choose. In the second and third groups of participants, the pop-up suggestion was accompanied by either text-based health information (e.g., “This alternative contains less sugar”) or image-based health information (a healthy heart logo). The fourth group – the control group – received no suggestions for alternative products.

The result: a higher percentage of nudged healthier products were chosen in the suggestion-only condition (38%) than in the control condition (30%), whereas the addition of text- or image-based health information did not boost effects. 

Are you aware of any other nudges that promote healthier food choices? Feel free to comment or get in touch: hello@green-nudges.com

What unsustainable behavior needs to change:

A NBC study published in 2018 revealed that cigarette butts are a more detrimental form of pollution compared to plastic bags. Startling statistics emerged, indicating that cigarette butts have been the most commonly collected item on beaches worldwide for 32 consecutive years. Over that period, more than 60 million cigarette butts were collected, accounting for approximately one-third of all collected objects. Further studies have shown that a single cigarette butt can pollute anywhere from 500 to 1,000 litres of water. 

People often discard cigarette butts due to a combination of convenience, habit, and a lack of awareness about the environmental impact. Many smokers just do not think about the environmental consequences leading to their careless disposal.

The Green Nudge:

In 2015, Hubbub ran a behavioural experiment to combat cigarette littering. Instead of struggling to find a disposal spot and potentially littering the street, individuals were engaged in a fun quiz through „Ballot Bins“ running on Villiers Street in London. These engaging bins posed buzzing questions like „What came first: Chicken or Egg?“ to encourage responsible disposal of cigarette butts which led to a 20% reduction in butt littering within a 6-week timeframe. Additionally, the magnetic letters on the bin could be rearranged to create new social polls, ensuring continued engagement even if the initial question loses its buzz.

What unsustainable behavior needs to change:

Lebanon faces significant challenges in managing plastic waste due to a high rate of plastic consumption and inadequate waste management infrastructure. Around 11% to 13% of the Municipal Solid Waste generated in Lebanon consists of plastics. Although some of it is recycled, most is either landfilled or openly dumped and incinerated. 

Despite the harmful effects of plastic on the environment, most restaurants continue to provide plastic cutlery with their delivery orders by default, even when customers may not necessarily need or want it. Concurrently, customers do not usually care to ask for the exclusion of cutlery. As such, unutilised plastic cutlery is discarded, resulting in unnecessary (yet avoidable) environmental costs. 

There are several biases and bottlenecks that prevent customers from opting-out of receiving plastic cutlery, even when they do not need it. Most customers are susceptible to the status-quo bias (the tendency to stick with the current state of affairs, i.e., the default inclusion of plastic cutlery), or social norms bias (the tendency to follow what others are doing), or to cognitive overload (although they care about the environment, it may not occur to them to request the exclusion of cutlery from their meals because they are focused on other tasks).

The Green Nudge:

What unsustainable behavior needs to change:

Liseberg, Sweden’s largest amusement park, aims to become a global leader in sustainable park operations by 2025. A key milestone in this endeavour is minimising the climate impact of food and beverage sales.

The Swedisch Behaviour Lab (Beteendelabbet) was hired to examine and investigate how nudging and behavioural design could be used to increase the sale of vegetarian food at one of the park’s restaurants called Café Taube. 

The Behavior Lab discovered three key insights by analysing and exploring the decision-making environment of customers, as well as conducting interviews and observing customer behaviour:

1. The menu placed outside the restaurant only displayed meat and fish dishes 
2. Numerous customers experienced “decision stress” and tended to select dishes prominently displayed at the beginning of the menu
3. The vegetarian options were depicted as less appealing, being positioned as a mere alternative to meat rather than showcasing their own enticing qualities as delicious dishes

Based on these behavioural insights, The Behavioral Lab developed designs and methods to make it easier and more attractive to choose the vegetarian option.

The Green Nudge:

What unsustainable behavior needs to change:

Waste from packaging poses a serious environmental problem. The US Environmental Protection Agency reports that there were more than 80 million tons of packaging produced in 2018, with two-thirds of this packaging made of plastic or paper. Once the packaging is no longer in use, some of it is recycled, but much of it ends up in landfills. In 2018 alone, landfilled plastic and paper packaging waste amounted to 10.09 and 6.44 million tons, respectively, accounting for 11% of the total landfilled waste in the United States. 

Despite the potential environmental and financial benefits of reducing excessive packaging, many products remain over-packaged, with layers of superfluous packaging added to the more necessary ones. 

An international research team looked at how consumers respond to such overpackaging, where unnecessary paper is added to plastic. Across eight studies with consumers from the Netherlands, US, and UK, they found that people judge the combination of plastic & paper packaging as MORE eco-friendly than identical plastic packaging without the paper. 

Our brains perceive paper as eco-friendly, while plastic is rather linked to images of polluted oceans. Driven by their biassed environmental friendliness perceptions, consumers are willing to pay more for over-packaged products and are more likely to choose them. 

The Green Nudge:

What unsustainable behavior needs to change:

Waste production and management have become major issues since we shifted from a reuse and repair culture to a more linear economy. This in turn has pushed us to mass overconsumption. Unless we change our consumption habits and shift our economic model to a more circular one, waste issues will continue to worsen – especially as our global population increases. Waste disposal creates significant environmental and social problems such as: occupying large amounts of land, contaminating underground water resources, soils and air. There is an urgent need for industries and organisations to innovate and change. 

At the same time, it’s also necessary for households to manage waste properly. As much as there is a lack of will and intentions for some people, there might also be a lack of knowledge. This inability to sort waste accurately can lead to recyclable materials getting contaminated, leading to 20% of recyclable products ending up in landfills yearly.

The Green Nudge:

What unsustainable behavior needs to change:

You may have seen videos of tourists frantically piling up food on their plates at hotel buffets. Unfortunately, this gluttonous behaviour contributes to the significant issue of food waste. Buffets are designed to offer a wide variety of options catering to different tastes and preferences. By design, the self-serve nature of buffets can lead to people taking more food than they can eat, as there are no portion control measures in place. 

If people do not fill up their plates with as much food as possible, they might feel as though they’re losing out on the opportunity to try a variety of foods or getting their money’s worth. One potential psychological explanation for this behaviour is called “Loss aversion.”

Additionally, people may also experience social pressure or expectations to consume more food when surrounded by others who are overfilling their plates. This can lead to a sense of conformity or a “fear of missing out” if one doesn’t fill up their plate in the same way; thereby worsening the problem of food waste.

The Green Nudge:

Norwegian researchers Steffen Kallbekken & Håkon Sælen wanted to see if they could nudge hotel guests to waste less food by changing the way the food was presented. In two treatments, the researchers manipulated external cues to measure their impact on average food waste (in kg). 

In the first treatment they reduced average plate size from 24 to 21 cm, combining a social cue (plate shape and size delineate norms for appropriate amounts of food to eat at a meal) with a visual illusion (smaller plate size can lead to biassed perceptions of how much food is consumed or served).

In the second treatment, they provided a more direct clue by displaying a sign at the buffet. It reads “Welcome back! Again! And again! Visit our buffett many times. That’s better than taking a lot at once.” This signal indicates that it is socially acceptable to serve yourself more than once. 

The results were impressive. Reducing the plate size led to a 19.5% reduction in food waste, while the sign at the buffet led to a 20.5% reduction. 

While the study has some limitations, such as a small sample size, the findings were supported by their own observational study and other studies that show how social influence or plate size can affect food behaviour.

What unsustainable behavior needs to change:

Radiators in public buildings such as schools, libraries, etc. are often wasting energy in rooms that are not being occupied or where windows are opened. 

According to a study conducted by the Department of Energy and Climate Change in the UK, leaving a single window open overnight during winter can increase heating energy consumption by up to 8%. This means, if a person’s heating bill for the winter is $1000, leaving the window open for one night could potentially cost an additional $80.

The core problem: People cannot see if the radiator is hot, medium, or cold making it difficult to know if they should turn down the valve. 

The Krukow consultants worked together with the city of Copenhagen to investigate what kind of nudge solutions could be developed to reduce heat waste from radiators. 

The findings can be transferred to both companies and private households. 

Here is what Krukow found:

1. The main behavioural barrier for turning off a radiator when i.e., opening a window is lack of visual feedback. When opening a window, we pay little attention to the radiator and forget to put a hand on it to feel if it is hot or cold. 
2. There is nothing in the visual design of the radiator reminding people to check the heat of the radiator before opening the window.
3. When a window is open near a warm radiator, the heat goes up to compensate for the drop in room temperature making the heat of the radiator instantly increase even more. 

In a nutshell: People often fail to change unsustainable behaviour when unable to assess abstract factors like room temperature or air circulation.

The Green Nudge:

Krukow came up with the idea to add heat-sensitive paint to radiators, changing colour from blue to red to provide visual temperature feedback. 

When a radiator in a room compensates for a drop in temperature by increasing heat output, the heat-sensitive paint on the radiator’s surface reacts to the immediate increase in temperature by changing colour. This colour shift provides an immediate visual cue to pupils, employees or visitors in public buildings, indicating when to turn off the radiator. This way the City of Copenhagen could effectively reduce energy waste and save money on heating bills.

Visual feedback, like the blue stripe on a baby’s diaper or a razorblade’s colour change, makes the abstract concrete and is a great way to trigger behaviour change, as demonstrated by the radiator paint example.

What unsustainable behavior needs to change:

For decades, consumption has been celebrated as a sign of wealth, with little regard for the consequences. Western societies have especially become throwaway cultures, ignoring the pollution, hazardous working conditions, or CO2 emissions resulting from increasing consumption. For many years we didn’t consider the impact that our choices have on the environment and other people, such as buying fashion, cars, or meat.

But research from the Economist Intelligence Unit indicates that consumers actively seek information about the climate impact of the products they buy: since 2016, the number of Google searches for sustainable goods has risen by 71% worldwide.

Unfortunately, they often lack information about a products‘ sustainability, such as its carbon footprint. This information gap can hinder consumers‘ ability to make informed choices and support sustainable practices.

Grocery shopping can be especially challenging, with numerous products to evaluate and little time to do so. It is impractical for consumers to i.e. assess the carbon footprint of each product and its alternatives all on the shelf.

The Green Nudge:

To address this challenge, the Norwegian online supermarket, Oda, introduced an innovative solution to simplify climate-friendly shopping. They created a “climate receipt” that displays the price of purchased food items as well as their CO2 emissions.

In order to better show customers how much or how little is, say, 2.7 kg of CO2 per kilogram, they grouped all products into four different emissions categories: low, medium, high and very high – illustrated with the colours green, yellow, orange and red. Oda’s emissions data was sourced from Cicero (Centre for International Climate Research), a Norwegian centre for climate research that calculates emissions over the whole lifecycle of a product. Customers can thus see the impact of their product choices on the planet, and given that Oda gives this information for all purchases, they can also monitor how their own behaviour is changing.

The “climate receipt” allows consumers to make different choices: since they launched the climate receipt, meat sales have dropped – whereas sales of meat alternatives have grown by 80%, with customers buying 50% more fruit and vegetables. This demonstrates once again that customers will adopt more climate-friendly behaviours if you make their environmental impact more salient.

What unsustainable behavior needs to change:

Herbicides and Pesticides are harmful for the environment, the animals and humans in it. An initiative by the Dutch Ministry of Infrastructure and Water Management to reduce the use of pesticides was unfortunately not successful – people just switched to kitchen remedies and organic acids, such as vinegar. As it turns out, many people do not know that using vinegar can still be harmful for the biosphere – ideally weeds and pests should be removed manually or with hot water. This is especially true for driveways or hard paths in the garden, where the herbicides are most often applied.

A study by Dutch behavioural consultancy Dijksterhuis & Van Baaren examined the factors playing into the use of vinegar as herbicide and tested nudges and communication formats to make people shift to the less harmful behaviour. 

As it turns out, what makes people use vinegar is not so much the health and sustainability aspect, but the fact that they did not know it was harmful. Also vinegar appeals to people, because it is: 

• cheap,
• convenient,
• effective and
• available everywhere 

Therefore, the alternative behaviour presented to the vinegar users, needed to fulfil the same criteria. They identified that using boiling water from the kettle fulfilled all of those criteria and was therefore chosen as the key behaviour. Vinegar users were also found to be significantly more ashamed of an untidy garden than non-vinegar users – so communication around the nudge played on that feeling. Lastly, to change behaviour, the nudge needed to break a habit – because weed control and the way it’s done is a habitual behaviour.

The Green Nudge:

A sticker on a kettle reminding people to use boiled water as an herbicide promises to be the most effective nudge. First of all, it reminds people at the right time and location – where the behaviour should occur. Secondly, it guides them to the desired behaviour, without much explanation. The sticker can be sent with additional information in the mail at a low cost; while a selection of 3 different designs for the stickers increases the likelihood that people will be willing to place the sticker on the kettle. 

Rolling out this campaign under the Dutch Ministry of Infrastructure and Water Management would greatly increase its chances of success compared to the original initiative.

More information on the survey, the identified target groups and alternative examined nudges can be found here (for Dutch readers).