What unsustainable behavior needs to change:
In buildings with multiple apartments, common waste disposal areas are often littered. Cigarette butts, small papers and even bulky waste are placed outside of rubbish bins on the floor. The mess is costly as it implies fees for extra cleaning, possible health hazards and lower psychological well-being of tenants.
There are many approaches to motivate cleaner behaviour. Let’s focus on the following four:
- Monetary: Highlighting financial consequences of violating established norms
- Norm: Emphasizing the “appropriate” behaviour (proper disposal)
- Reputation: Making use of watchful eyes that elicit a feeling of being monitored (at least in less frequented locations)
- Ecology: Showing pictures of pristine nature, such as landscapes, or sometimes specific features of nature (e.g., a panda)
The Green Nudge:
In a field experiment involving 71,000 participants, researchers tested four posters building on the aforementioned four approaches compared to a control group with no poster. Two posters directly referenced waste, one highlighting the financial benefits of a clean disposal area and the other using comic-like pictograms to show proper disposal. The remaining two posters did not refer to waste at all (“implicit”): one of which depicted watchful eyes and the other a local natural landscape. The effect of the respective posters was evaluated over a period of 7 weeks.
The researchers found that the financial intervention had hardly any effect on littering whereas the norm pictogram even backfired: it led to more littering compared to the control group. In contrast, the reputation-based intervention (watchful eyes) and ecology-based one (nature picture) reduced littering over time by 4.7%. Overall, the implicit approaches that made absolutely no reference to waste were more successful at keeping waste disposal areas clean.
This study provides early evidence of different nudges to effectively reduce littering in communal spaces. Even simple nudges like posters can be low-cost interventions to encourage pro-environmental behaviour. The researchers are now conducting a follow-up study to build on these findings.