“Clear Bag Policy”: shifting waste management with social norms
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:
Reported by Akbulut-Yuksel and Boulatoff (2021), a Canadian municipality implemented a clear bag policy to incentivise households to manage their waste better. Departing from monetary incentives, this municipality decided to use subjective and personal norms to nudge people.
Instead of having opaque black bin bags for general waste, the municipality distributed see-through bags. Firstly, it enabled waste collectors to screen bags and refuse them if they thought some materials could be reallocated to the recycle or organic category. Secondly, having passersby, such as neighbours or people from their community, who could see into their bags – added some social pressure to stick to the subjective norm of recycling and sorting waste properly. It also contributed to increased pressure regarding their internalised values and moral obligations to be good citizens.
The result: an increase in recycling by 15% and a decrease in overall municipal waste by 27%. Not only did people start sorting their waste better, but a spillover effect occurred which impacted people’s consumption habits. Simultaneously, the overall amount of waste generated yearly also decreased.
As much as it proved to be effective, this experiment raises questions about the morality of social norms, external influences and how it applies to different cultural contexts. How would this look different if, say, it was deployed in Europe?
Are you aware of any other nudges that use social norms? Get in touch: hello@green-nudges.com
From Lucie Mathieu who graduated with a master’s in Psychology of Economic Life. She has a strong interest at the crossroads of behavioural sciences, sustainability and social entrepreneurship. Currently, Lucie works in a social enterprise startup and advises Sustainacy (a B2B platform aiming to foster employees‘ sustainable behaviours at work, through the use of behavioural science, gamification and education).
Carbon labels on restaurant menus can impact food choices
What unsustainable behavior needs to change:
What do you envision when you think of fast food or food delivery? Perhaps pizza, burgers, tacos, and döner kebab come to mind. While there are increasingly healthier options available, a significant portion of fast food choices still include meat.
A meat-based diet not only harms your health but also damages our planet. It leads to significantly higher CO2 emissions compared to more sustainable dietary choices. Moreover, fast food entails various negative externalities, including excessive fuel consumption for supply and processing, wasteful packaging, food waste, and water contamination.
But let’s stick to CO2 emissions. A survey conducted by Carbon Trust among 10,000 individuals in 8 European nations revealed that 66% of respondents favoured carbon labelling on products. However, it is unclear whether they are merely professing their support or genuinely acting on their intentions.
The Green Nudge:
The UK-based Mexican restaurant chain, Wahaca, decided to highlight the climate impact by including a carbon label next to each menu item.
They partnered with Swedish startup Klimato, which calculates and communicates the climate impact of food, to develop a labelling system that uses CO2 equivalents as a base. The calculations include the emissions for growing all the ingredients, as well as those generated when transporting, storing and cooking them.
Wahaca is now using carbon labels in three different dimensions:
- Low carbon (CO2e 0.6kg or lower): i.e. sweet potato burrito (0.46kg)
- Medium carbon (CO2e 0.6kg – 1.6kg): a grilled chicken club quesadilla,
- High carbon (CO2e 1.6kg or higher): such as a chargrilled steak burrito (3.04kg CO2e)
Although we lack concrete evidence in the Wahaca example, showing that highlighting the carbon impact affects food choice, multiple recent studies and trials have indicated that labelling can influence behaviour.
Psychology researchers from the University of Würzburg conducted a study which demonstrated that when individuals were presented with menus containing low-emission options, such as coconut curry with tofu instead of beef, the CO2e emissions decreased by almost one-third. Carbon labelling alone resulted in a 13.5% reduction in CO2e.
Researchers from Johns Hopkins University arrived at similar conclusions. In a randomised clinical trial involving 5,049 adults in the United States, 23% more participants in the high-climate impact label group opted for a sustainable option (i.e., non-red meat), and 10% more participants in the low-climate impact label group chose a sustainable option compared to the control group.
Gold star stickers on trash bins increase recycling rates
What unsustainable behavior needs to change:
Aotearoa New Zealand sadly isn’t amongst the world champions of recycling. Compared to other countries, recycling rates are much lower. According to Recycling New Zealand, in Auckland alone, the amount of waste sent to landfills is expected to double in the next 10 years!
More numbers?
- NZ generates 17 million tons of waste each year, while 76% of it goes into landfills
- 40% of household waste that could be recycled, goes into the wrong bin
- Each year, approximately 2 billion plastic containers aren’t getting recycled
Following the lockdown of the COVID19 pandemic, recycling rates worsened. In Christchurch particularly, rates plummeted, with material from only 48% of garbage collection trucks being recycled in June 2020. The reason: too much contamination resulting from poor sorting by residents. Even the local EcoSort facility had to close temporarily due to many residents failing to, for example, remove bottle lids or exclude thin plastic films, such as cheese wrappers.
The question was: How to motivate people to better sort their garbage and keep recycling streams clean? Punishment or reward? Sticks or carrots?
The Green Nudge:
The Christchurch city council introduced a public reward (and shaming) system that builds on the idea of social norms. Anyone who does an excellent job at sorting the right, properly cleaned rubbish items gets a large gold star added to their kerbside recycling bin, visible for the whole neighbourhood to see. The star uses a neat pun, saying: “Thanks for bin great”.
The result: In 2020, more than 177,000 bins have been checked, with nearly 50,000 gold stars issued (~31%). They not only rewarded successful recyclers – compliance staff also gave out education notices (to ~61%) and removed the bins of those who repeatedly failed to recycle properly (only ~260 in total). The council considers the Green Nudge initiative as a great success: In only a few months, the number of successful recycling trucks headed to the sorters increased from 48% to 80%.
So, what are the underlying reasons that the nudge worked? We’ve seen other social imitation nudges like in the energy supplier or shopping trolley examples. But the gold star stickers are more visible on a public level and have a stronger shaming element.
MIT research scientist Erez Yoeli, who studies how altruism works, would probably explain this as ‘our collective desire to be seen as generous and kind instead of being selfish’. But Kenrick and Griskevicius might argue that “going green to be seen” might indeed be status-driven social signalling and thus be anything but altruistic.
Full article in The Guardian.
Social imitation inlays in shopping trolleys to promote vegetable purchases
What unsustainable behavior needs to change:
Let’s start with two questions:
- What is the recommended daily amount of veggies you should consume in order to follow a healthy diet?
- How many people actually meet the daily intake of vegetables
To speak for the Netherlands, only 6% of people aged between 1-79 years consume the recommended daily amount of 250g of veggies. The German nutrition organization even recommends eating 400g veggies and 250g fruit per day. But as only 13% meet the recommendation, the organization started the “5 per day” initiative to promote a healthy plant-based diet. It should be no surprise to find similar data in other countries.
Why should we care? Besides the comparably higher CO2 emissions that come with meat-based diets and the lack of animal welfare, an inadequate vegetable consumption is a public and individual health concern.
So how can you nudge someone to make more healthy food choices such as veggies?
The Green Nudge:
Supermarkets can have a considerable impact on people’s food choices. In a 2020 quasi-experiment in a Dutch supermarket with 244 participants, researchers tested two Green Nudges that used the idea of social imitation.
The researchers put inlays in shopping trolleys that
a) communicated a social norm message about vegetable purchases and
b) showed a designated place to put vegetables
The result: 73.3% of people noticed the green inlay in the shopping trolley. The social imitation intervention led to a statistically significant increase in grams of vegetables purchased. This was especially true for people who bought groceries for less than three days, which could be explained by a more impulse and thus more influenceable behaviour.
Social scientists have demonstrated the influence of peer behavior in a host of areas. We’ve been building bigger houses, driving heavier vehicles, flying to remote destinations or engaging in a host of other energy-intensive activities. A dominant reason we are doing these things is our tendency to behave as our peers do. But experiments like this give reason to believe that peer effects could be similarly beneficial to our climate future and individual health improvements.
Full article in ScienceDirect.
Opower’s neighbour comparisons. Saving energy by making sustainable peer action salient.
What unsustainable behavior needs to change: Let’s go back a couple of thousand years in time. One of our hairy ancestors observes another gatherer picking some fruits from a bush and eating them. Some time later the fruit picker is still alive and well. This day she learned that eating those fruits won’t kill her or her family.
Evolutionary psychology suggests there are five ancestral forces that have shaped human perception and behaviour. In this case: Social imitation.
It refers to the important lesson that human beings learned a very long time ago and which secured our survival: imitating others is the most efficient way to learn. Our brain is therefore wired to do what the majority does.
Unfortunately, the majority of people often influence each other into adverse habits – especially when it comes to the environment. Social scientists have demonstrated the influence of peer behavior in a host of areas. We’ve been building bigger houses, driving heavier vehicles, flying to remote destinations or engaging in a host of other energy-intensive activities. A dominant reason we are doing these things is our tendency to behave as our peers do.
The Green Nudge: There’s reason to believe that peer effects could be similarly beneficial to our climate future.
Utility Companies, for example, have found that customers reduce their electricity usage significantly when told how their consumption compares with that of neighbors.
Opower, a home-energy-management company owned by Oracle, has helped deliver these customer-comparison reports to millions of households served by utilities around the globe; it boasts that the program has helped save enough energy to power San Francisco’s homes for more than 10 years.
Google, the manufacturer of smart Nest thermostats, has incorporated the approach into its product: It rewards customers who choose energy-efficient settings with green leaf icons in their monthly usage summaries, and compares the number of leaves earned with those of other Nest users in the area.”
From Robert H. Frank’s book, Under the Influence: Putting Peer Pressure to Work.