The Effects of an Ambiguous, Negative Sign Prompt and a Clearly-Stated Positive Sign Prompt on Intentions to Litter

Horsley, A. D. (1988). The unintended effects of a posted sign on littering attitudes and stated intentions. Journal of Environmental Education, 19, 3, 10-14.
A literature review revealed that sign prompts can be effective in reducing the amount of litter. In order to further investigate the effects of prompts, a questionnaire was given to university students and campers. The questionnaire was designed to determine the effectiveness of two different types of prompts. The first prompt was rather ambiguous and negative ("We treat litterbugs like all insects") whereas the second prompt was clear and positive ("Please save our landscapes: don't litter"). The questionnaire contained items designed to reveal intentions to litter.

Thirty percent of participants responded that the "Please save our landscapes: don't litter" prompt would make them think about the litter problem. Furthermore, 20% indicated that this prompt would influence their decision not to litter. On the other hand, 40% said the "We treat litterbugs like all insects" message would actually make them want to litter.
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