Comparative Effects of “Do” Versus “Don’t” Formatted Signage on Littering

Methods to discourage the behavior of littering and promote the proper disposal of trash have been studied for many years; however, littering remains a problem in various settings (Almosa, Parkinson, & Rundle-Thiele, 2017, “Littering Reduction: A Systematic Review of Research 1995–2015,” Social Marketing Quarterly, 23[3], 203–222). The purpose of this field study was to further explore features and influences of signage posted alongside trash cans—signs aimed at discouraging littering and encouraging pedestrians to make use of the nearby receptacle when appropriate. To evaluate littering across sign versus no-sign preparations and to examine whether littering was differentially sensitive to symmetrically worded “do” versus “don’t” sign conditions, we prepared an alternating-treatments design with condition reversals. Results indicated that the condition without a sign was inferior to conditions with signs and that there were negligible differences between the “do” and “don’t” sign conditions. We discuss our findings in the context of methodological and social validity considerations.