Written by Yaffa Segal '25
Edited by Lisa Liong '25
Littering is considered to be one of the most important factors in fighting climate change. It causes a severe strain on the environment, and as a result, governments are now devoting a large amount of resources toward research and development of anti-littering measures. A growing number of studies now focus on the internal behaviors that lead to littering, rather than the littering itself. There is a current gap in research on “theory-driven” measures that use psychological evidence to create waste-management techniques .
Researchers from Austria wanted to determine the most effective way to reduce littering in their communities. They wanted to see which type of preventative measures would be the most effective at deterring people from littering. They conducted a randomized controlled trial using over 400 community waste disposal sites in Vienna to test four different types of posters for littering prevention.
Posters were proposed as a means of maintaining cleanliness because they were deemed the most economical option. Other ideas included lemon-scented air fresheners and appointed officials to monitor the waste disposal sites personally. This study was conducted in low-income social housing in Vienna, so it was decided that the best financial option would be to test out the posters.
The first poster type used monetary information as a means of preventing littering. This would depict some kind of financial punishment for littering or incentive for proper behavior. The next was called “depicted injunctive norm” which would encourage people to dispose of their waste properly because it is the right thing to do. This poster would, for example, have a picture of the correct way to dispose of trash, which would ideally model the correct behavior. Next was the reputation-based intervention, or “watching eyes”, which would prompt people to avoid negative behaviors, such as littering because they are being observed by some kind of outside authority. This approach is assumed to be effective because of implied harm to reputation or implied financial punishment. Lastly, a nature picture was also used as a means of preventing littering in these areas. The idea is that a picture of an ecologically rich landscape would subconsciously remind people of the beauty of the planet and subsequently prevent them from doing anything to harm it.
(Gangl K, Walter A, Van Lange PAM, 2022)
All of these approaches can be divided into two categories: implicit and explicit. The monetary and norm-based approaches are considered to be explicit, because they specifically state that there will be a financial incentive or a social expectation for the proper disposal of litter. The watching eyes and nature picture, however, were implicit. They did not state anything specifically about littering, however their presence elicited a sense of discomfort, causing corrected behavior.
The researchers measured the amount of litter on the streets in the region near the waste disposal sites and compared them to one another. Overall it was found that the implicit approaches—the watching eyes and nature picture—were more effective in maintaining a clean waste disposal site. This is supported by previous studies.
One study found that pictures of animals trapped in plastic were an effective way to encourage an increased amount of recycling sorting in an office building in Vancouver, BC .
It seems that when people are able to see the direct consequences of not recycling, they are more likely to be mindful of their surroundings and go the extra mile to dispose of their waste properly. The pictures of animals and nature elicit feelings of guilt, which appears to be the most effective way to encourage sustainable behaviors. This research can help inform future anti-littering initiatives in Vienna and around the world.
1. Gangl K, Walter A, Van Lange PAM. Implicit reminders of reputation and nature reduce littering more than explicit information on injunctive norms and monetary costs. Journal of Environmental Psychology. 2022 Nov 17;101914.
2. Luo Y, Douglas J, Pahl S, Zhao J. Reducing Plastic Waste by Visualizing Marine Consequences. Environment and Behavior. 2022 May 1;54(4):809–32.
3. The Circular Economy and Benefits for Society [Internet]. Club of Rome. [cited 2022 Nov 27]. Available from: https://www.clubofrome.org/publication/the-circular-economy-and-benefits-for-society/