'Do Not Litter' Signs Can Be Counterproductive
When signs prohibiting certain behaviors are blatantly ignored, it inspires others to act in antisocial ways.
Do Not Litter. Keep Off the Grass. Clean Up After Your Dog.
Sternly worded signs adorn our parks, plazas and playgrounds, reminding visitors to follow certain codes of conduct. But a newly published study finds that, under certain circumstances, these admonitions seem to have the opposite effect.
Researchers in the Netherlands present evidence that if certain rules are clearly spelled out, and you note that others have been disregarding them, you're more likely to break them as well. What's more, you are also more likely to ignore an entirely different directive.
Writing in the journal Group Processes and Intergroup Relations, psychologist Kees Keizer and two colleagues from the University of Groningen describe a series of experiments. All were conducted in an alley where people park their bicycles while shopping in nearby stores.
The experiments all had the same basic structure. Researchers attached a flyer to the handlebar of a parked bicycle, which read “Happy Holidays,” and gave the name of a fictional sportswear shop. When the shoppers retrieved their bicycles, researchers noted whether they took the flier with them (there were no trash cans in the alley) or threw it on the ground.
In their first experiment, Keizer and his colleagues confirmed the results of a 2008 study that found people are more likely to litter an already-littered area. Fifty-three percent of the cyclists took the flier with them when the alley was clean, but only 39 percent did so when it was strewn with “a few empty soda cans, flyers, plastic bags and candy wrappers.”
In their next experiment, the researchers similarly littered the alley but also hung a large anti-littering sign on the wall. Under those circumstances, only 28 percent of people took the flier with them. Repeating the experiment, they got a similar result: Thirty percent of the cyclists didn't litter.
Either number is a significant drop from the 39 percent who tossed the flier aside when no sign was present. This suggests evidence that a clear rule that has been flouted disinclines others to obey that directive.
For their next series of experiments, the researchers sprayed the alley wall with graffiti, creating “several improvised tags in different colors.” They then repeated the litter experiment.
They found the graffiti had an almost identical effect as strewing garbage on the ground: Only 38 percent of cyclists took the flier with them rather than dropping it on the ground. When a “No Graffiti Allowed” sign was hung on the wall (a message the supposed taggers had blatently ignored), that number went down to 31 percent.
However, when the graffiti was cleaned up and a "No Graffiti Allowed" sign was visible, 68 percent of cyclists took the flier with them – the highest percentage of any of the experiments. However fleetingly, the cyclists took note of the fact that their fellow citizens were obeying the law (in this case, the no-graffiti rule), and this inspired them to do the same (by avoiding littering).
As Keizer and his colleagues note, these findings have direct implications for policymakers. They suggest removing evidence of rule-breaking behavior, such as litter or graffiti, should be a priority — especially in areas where signs directly forbid it. It appears antisocial behavior is contagious, and the more brazen it is, the more power it has to spread.
The researchers sum up their advice with their own admonitory statement: “Do not place prohibition signs where the rules are not enforced.” That’s a little too long to fit on a sign, but they make their point.
Staff writer Tom Jacobs is a veteran journalist with more than 20 years experience at daily newspapers. He has served as a staff writer for The Los Angeles Daily News and the Santa Barbara News-Press. His work has also appeared in The Los Angeles Times, Chicago Tribune and Ventura County Star.