Handing out stickers against littering in Rotterdam

Rubbish bags or sometimes even discarded furniture lying around rubbish containers. If you live in Rotterdam, chances are you recognise this image. The Municipality of Rotterdam is doing a lot to reduce these 'side placements'. But what really works? And what can the municipality do with the insights from behavioural science? To get answers to this, the Municipality of Rotterdam and Erasmus University Rotterdam jointly set up the Behavioral Insights Group Rotterdam (BIG'R) in 2017. The study on reducing juxtaposition is part of Dewies' PhD thesis and is one of 25 cases in which the municipality and the university worked together.

Sticking stickers

In this case, they managed to drastically reduce street litter simply by handing out stickers. "In neighbourhoods where there are many side placements, the municipality goes door to door. In one of these neighbourhoods, during this call, stickers were handed out that read 'I keep our street clean' with a request to stick them visibly on their house," the PhD student explains. In the neighbourhood where stickers were handed out, the number of days in the week when litter was found decreased by two-thirds. While in the neighbourhood where only conversations were held (without handing out stickers), nothing changed.

A stunning result, but what is a possible explanation for the success? "The stickers are not only a visual reminder, you also communicate social norms in the street this way," explains Dewies. Not every intervention proved so successful. In one municipality department, it was policy that employees had to wear keycords to be recognisable in the workplace, but many did not. To encourage use, various nudges (literally translated: nudges) were tried, such as a mirror with a keycord on it that makes it look like you are wearing one yourself.

Freedom of choice remains

None of the interventions proved effective. Indeed, the researcher thinks some stickers were taken away by employees because they caused irritation. "They were fine quality stickers, but there was little understanding of the measure," he says. In this case, presumably the lack of support for the keycords could not be nudged. According to the researcher, this shows that even when nudged, people retain freedom of choice.

According to the PhD student, the fact that the nudge did not work does not mean that there was something wrong with it, but that its effectiveness is context-dependent. You have to research that context well first, his thesis shows, otherwise there is a danger of nudging without success. "I am a behavioural specialist but with my scientific knowledge I do not yet know the context. I need the experience and knowledge of the municipality for that. It is important to listen carefully to each other and work closely together. We have developed a unique format for that at the Behavioural Insights Group."

Fireworks at the Kuip

Another study dealt with the illegal setting off of fireworks at football stadium the Kuip. Here, no interventions were made to influence behaviour, but the research focused on understanding the behaviour. Through a supporters' association and the club, contact was made with fans who sometimes set off fireworks, who were then interviewed. "They were found to not associate setting off fireworks with violence or aggression at all, contrary to common preconceptions. They feel they are supporting their team with this and also do not see it as aggression towards the other team."

The advice in this case was not to apply a nudge but to start the conversation with different stakeholders, including the supporters. That way, you can reach compromises together to increase safety. Understanding the target group is crucial in all cases, as a case study of the repayment of over-received welfare shows. The letter the municipality sent about repayment received very little response. The researchers drafted a new letter to which more people responded who then also made repayment arrangements more often.

Packaging the message differently

Dewies: "Hammering on repayment doesn't work, because people often have financial worries and then clam up. You want to reduce stress. The new letter explicitly stated that you can come to a solution together with the municipality. With a letter, you have to think about what information leads to a desired action. You can do this with other letters from the municipality as well. If you know how to do it, it is often just a small effort."