Positive vs. Negative Prompting for Litter Control: A Systematic Field Evaluation of Relative Effectiveness
Attempts by behavior scientists to test interventions designed to promote environmentally-responsible behavior (ERB) have been documented for decades. Numerous behavioral scientists have looked to community-based interventions to decrease environment-destructive behaviors, as well as to increase environmental-protective behaviors (Geller, 1995). Litter is one of the most obvious examples of environmental degradation. Litter, defined here as misplaced waste material (Geller, Winett, & Everett, 1982), is a form of environmental pollution that not only degrades the quality of the environment but also proves costly to taxpayers. A wide variety of ecological and monetary benefits result from a decrease in litter. The current research examined the effectiveness of positive vs. negative antecedent messages to reduce littering behavior.
A methodology similar to that used by Geller, Witmer, and Orebaugh (1976), in which handbills containing weekly supermarket specials and special anti-litter message prompts were distributed at local community shopping centers, was used in the current research. In the first study, handbills with no anti-litter messages were distributed for a one-week period to determine percentage of handbills that were littered, and to serve as a baseline. The total percentage of handbills littered was 38.5. A second, web-based, study was conducted to determine the six specific (three positive or gain-framed, and three negative or loss-framed) anti-litter antecedent messages to be added to the handbills. In the third study, handbills with anti-litter messages were distributed for a two-week period. Upon addition of anti-litter prompts, results revealed 36.09% of distributed handbills were littered. Although no significant interactions were found, several significant main effects were found for store location, distribution period, and gender. The gender effect, indicating women littered at significantly higher rates than males, is notable. Survey research in the area of gender differences related to environmental concerns often has often shown modest differences between men and women, with women frequently displaying greater levels of environmental concern as compared to men. Based on behavioral observations (instead of self-report measures frequently used in previous research), the present research demonstrated significantly more women littering than men.
Although slightly more handbills, in terms of total handbill numbers, containing positive antecedents were littered as compared to those containing negative antecedents (which might be interpreted as stronger impact of loss-framed messages), this difference was not statistically significant. Similarly, there were no statistically significant differences found among each of the six anti-litter messages.
Comparisons of Study 1 (baseline) and Study 2 (prompting intervention) revealed significantly more littered handbills in the baseline condition as compared to the anti-litter message condition. These results indicate a beneficial anti-litter effect of the prompts added to handbills.
Conclusions based on the findings of the three studies within the present research are discussed. Implications for policies, public campaigns, and follow-up research designs are noted. Suggestions for future research involving message prompts and ERBs are offered.