A balmy summer’s evening in the park. People are sitting on blankets everywhere, laughing, eating and enjoying the sun. Hours later, no one is left, but the lawn is not empty. Cans, plastic packaging and cigarette ends are strewn everywhere. The very next day, the same thing happens all over again. What sounds trivial is actually a social phenomenon: littering is contagious. This is where the ‘Agents of Change’ programme at the Hamburg University of Technology (TUHH) comes in. It shows how norms change and how small groups can have a major impact.
Many people take their cue from what others do. If the square is clean, they make an effort to leave it that way. If it is littered, their inhibitions drop. Researchers call these ‘social norms’. These are unspoken rules that influence our behaviour. The philosopher Cristina Bicchieri is researching how people make behavioural decisions. She describes it as follows: people follow norms when they believe that others are following them – and expect that others will do the same. In other words: we abide by rules when we believe they apply. And when enough people adhere to them, a new normality emerges.
Interactive computer simulation illustrates behaviour
In the ‘Agents of Change’ lab at the Hamburg Open Online University (HOOU), anyone interested can experience for themselves how social dynamics emerge. In the interactive computer simulation, they accompany people walking in the park and observe at what point sustainable behaviour ‘tips over’ into a positive trend – that is, becomes the norm. In the simulation, attitudes can be altered so that participants can then observe the effects this has on the behaviour of the people in the simulated world. Specific questions include:
- How many people are needed for others to follow suit?
- How effective are role models, reminders or small nudges?
- And what happens when the ‘Agents of Change’ lead the way consistently?
A long-term study by Humboldt University in Berlin investigated, across several major cities, why people leave litter behind and which measures help. The result: the problem is not a lack of bins, but convenience and indifference. Places where litter is already present – the so-called ‘littering hotspots’ – are particularly affected. The study also showed which measures work:
- Eye-catching bins with clear instructions
- Nudges: such as footprints leading to the nearest bin
- Poster campaigns with positive messages
- Community volunteers or ‘Waste-Watchers’ who are present in the neighbourhood
In Hamburg, the Waste-Watchers have been in action for years. They speak to people directly, raise awareness of the importance of keeping the area clean and thus reinforce the local social norm.
Change through understanding rather than pressure
According to the ‘Facts and Figures 2023’ report by Stadtreinigung Hamburg, around 18,500 tonnes of waste – such as litter collected from the streets – are disposed of each year. There are over 20,000 litter bins across the city, which are emptied up to three times a week. These figures show that keeping the city clean is a mammoth task. There is no shortage of litter bins, and yet a great deal of rubbish ends up on the streets. Littering affects not only the well-being of many people, but also that of animals, which may eat the rubbish or injure themselves on it. Keeping the city clean remains a shared responsibility. And it starts with the small things – with every single decision we make.
In Hanover, too, there is a remarkable example of community engagement. There, people from the drug scene meet regularly to clean the square in front of the Stellwerk – a central drop-in centre for people struggling with addiction. The project is called ‘Die Szene putzt’ (The Scene Cleans Up). What began as a clean-up campaign has now become a symbol: taking responsibility works by becoming part of the solution yourself. In this way, the participants demonstrate that active participation and dignity are possible even under difficult living conditions. Social change does not begin with pressure, but with understanding. And with a few people who take the first step. Researchers refer to this as ‘critical mass’: a small, visible group whose behaviour inspires others.
The ‘Agents of Change’ project is supported by the Institute of Management Accounting and Simulation. The scientific director is TUHH Professor Matthias Meyer, and Alexandra Eckert is involved as project manager, concept developer and author.
Agents of Change – setting sustainable action in motion
About the HOOU:
The Hamburg Open Online University (HOOU) is a consortium of Hamburg’s higher education institutions. The learning platform offers free online courses, podcasts and events to anyone interested. The HOOU comprises the Hamburg University of Applied Sciences, the Hamburg University of Technology, the Hamburg University of Fine Arts, the Hamburg University of Music and Theatre, HafenCity University Hamburg and the University Medical Centre Hamburg-Eppendorf. Its motto is: Knowledge 24/7. Those interested can access the learning programmes on offer at any time:
