English Audio Request

In the mid-1990s, the mayor of New York and his police commissioner focused on fighting signs of disorder and petty crime. Graffiti was removed, streets were cleaned, and signs of vandalism were cleared. This campaign was based on the broken windows theory (BWT). The BWT suggests that signs of disorder like broken windows, litter, and graffiti cause other types of disorder and petty crime. It was thought that removing signs of disorder would take away an important trigger of disorderly and petty criminal behavior. After the introduction of the campaign, petty crime rates in New York dropped. Since then, approaches based on the BWT have become popular worldwide (e.g., in various cities in the United States, Great Britain, the Netherlands, Indonesia, and South Africa).

The BWT is popular, but it lacks scientific support. Studies designed to test it have provided mixed results. There is also little evidence that broken window policing contributed to the sharp decrease in petty crime in New York. The BWT suggests that a setting with disorder triggers disorderly and petty criminal behavior, but it might be the other way around or both may be caused by a third variable.

Social norms(i.e., rules or conventions) refer either to the perception of common approval or disapproval of a particular kind of behavior (injunctive norm) or to particular behavior common in a setting (descriptive norm). Injunctive norms affect behavior because they provide information about which behavior is most appropriate. For example, the anti-litter norm is a widely held injunctive norm. The extent to which an injunctive norm affects behavior depends on how much the norm is on people's minds. An anti-litter norm will be more on people's minds when they see someone picking up a piece of litter or see the norm stated on a sign. Descriptive norms affect behavior because they provide information about which behavior is most common in a given situation. A littered setting shows that it is common to litter and will therefore enhance littering. Injunctive and descriptive norms can be in conflict, for example in setting where it is common to litter even though littering is disapproved of. Thus, settings described in the BWT as disorderly (e.g., a littered settings) can be thought of as settings where descriptive and injunctive norms are in conflict. The next question then is how behavior is influenced by it.

Injunctive norm information is more effective when accompanied by descriptive norm information that is consistent with that message. For example, a sign drawing attention to the anti-litter norm is more influential when placed in a non-littered setting. Thus, a setting with graffiti can trigger the creation of more graffiti because it inhibits the injunctive, anti-graffiti norm. The important question for the BWT is whether or not it also causes disorderly or petty criminal behavior in general. The question we will address is: Do more people litter in a setting where the anti-graffiti norm (injunctive norm) is in conflict with the descriptive norm (a setting where it is common to spray graffiti)?

Much conformity to injunctive norms is the result of people pursuing the goal of acting appropriately. However, people can also pursue a selfish goal directed at feeling better or at improving one's resources. All three goals can be conflict, and the weakening of one is likely to allow another to have more influence. In a given situation, the goal to act appropriately is weakened when people observe that others did not pursue the goal to act appropriately. In turn, a weakening of this goal strengthens conflicting selfish goals. For example, we predict that when people observe that others have painted graffiti, their concern for appropriateness will be weakened and selfish goals will be strengthened. Thus people don't necessarily copy the inappropriate behavior but may let concerns other than appropriateness take priority. In this way, one norm violation fosters violations of other norms, and disorder spreads from one kind of inappropriate behavior to other kinds.

We conducted experiments in common public spaces. There were no signs in any of the studies that the subjects were aware of being observed by the experimenter. We distinguished between a contextual norm (which the participant witnessed having been violated) and a target norm (a violation committed by the participant). We manipulated indications that the contextual norm was being violated. We predicted that disorder (violation of contextual norm) would spread (violation of target norm). For ease of description, ket us call the situation in which the contextual norm is violated (i.e., inappropriate behavior by others is being displayed) the "disorder condition" and the one in which it is not violated the "order condition".

In study 1, the setting was an alley located in a shopping area and commonly used to park bicycles. In the order condition, the walls of the alley were clean, whereas in the disorder condtion they were covered with graffiti. A standard sign prohibiting graffiti was in the alley, and every subject entering the setting at least glanced at it. Participants were all people who came to collect their bicycles. In their absence, a flyer had been to be removed to easily use the handlebar. Because there were no trash cans in the alley, "not littering" meant taking it with them. We counted throwing the flyer on the ground or hanging it on another bicycle as littering. The effect of violating the anti-graffiti norm on littering was quite substantial. Of the participants in the order condition (non-graffiti), 33% littered compared with 69% of the participants in the disorder condition (graffiti on the walls).

For study 2, we used a police rule as a contextual norm and "no trespassing" (as ordered by the police) as the target norm in the setting of a car park. Thus, both contextual and target norms were not general social norms but rules set up by the local police. A temporary fence closed off the main entrance for people who came to pick up their car, but a gap of about 50 centimeters was ledt open in the fence. We attached two signs to the temporary fence directly next ti the gap. One sign (our contextual norm) indicated that it was prohibited to lock bicycles toe the fence. The other sign (our target norm) mede clear that it was prohibited to use this entrance and that people had to use an alternative entrance to the car park, which required walking an extra 200 meters. In the order condition, four bicycles standing one meter in front of the fence were not locked to the fence. In the dislorder condition, the four bicycles were locked to the fence. The outcome variable was whether pedestrians followed the "no trespassing" sing (the target norm) and walked the extra 200 meters. Again, there was a clear effect. Oh the participants in the order condition, 27% stepped through the gap in the fence, compared with 82% of the participants in the disorder condition.

Would this also hold for a rule set by a private company that is not enforced with punishments? In study 3, a parking garage adjacent to a supermarket and health club was used in which the contextual norm established by the private company is to return shopping carts to the supermarket after loading groceries into one's car. A very visible sticker with the text: "please return your shopping carts" at the entrance doors of the parking garage focused attention on this request. In the order condition, the garage was clear of shopping carts. In the disorder condition, there were four unreturned shopping carts standing around in disarray. The target norm was the anti-litter norm. The outcome variable was whether or not participant littered a flyer that was placed under the driver's side windshield wiper of their parked car. Of the participants in the condition without shopping carts, 30% littered the flyer, compared with 58% of the participants where unreturned shopping carts were visible.

Is disorder only linked to visual cues$ \*$ of norm violation? Would the effect occur if the contextual norm was only audible? In our fourth study, we focused on a national law as a contextual norm. In the Netherlands it is prohibited by law to set off fireworks in the weeks before New Year's Eve. We wanted to find out, two weeks before New Year's Day, whether an offense against this national law would cause people to litter. The law about fireworks is well known, and its violation would immediately make the law salient in people's minds. The setting was a bicycle shed near a train station. In the order condition, there was no sound of fireworks. In the disorder condition, we set off firecrackers well within hearing distance of the participants but out of sight to prevent any visual cues. Of the subjects in the order condition, 52% littered the flyer compared with 80% of the subjects that heard fireworks being set off as they entered the bicycle shed.

Our conclusion is that, as certain norm-violatin behaviors become more common, they will negatively influence conformity to other norms and rules.