Nature posters enhance subjective but not objective cleanness in public housing: Evidence from a field experiment

Littering has negative effects on the environment and is seen as a sign of social disorder. A previous field experiment in public housing buildings showed that implicit posters using eyes and nature posters were more effective in reducing litter than explicit posters using norms and financial costs. The aim of the present field experiment was to test the effects of the nature poster against a control group. We assessed “objective” (based on ratings of photos) and “subjective” cleanness (based on residents’ reports) and explored the role of connectedness to nature. Results from 182 waste disposal areas and 739 residents show that nature posters did not enhance objective cleanness, but did enhance subjective cleanness after one month. This effect was partly accounted for by feelings of connectedness to nature in residents. Also, objective ratings indicated greater cleanness compared to subjective cleanness ratings. We conclude that nature posters had little impact on objective cleanness but enhanced subjective experiences of cleanness, which can be an important driving force for feelings of social order and comfort.