It has been hypothesized that viewing disorder and petty criminal behavior leads people to perpetuate such actions. If so, this has implications for local officials who want to "clean up" their neighborhoods.
However, evidence for this hypothesis has been lacking. Kees Keiser and coworkers (University of Groningen, The Netherlands) have now provided such evidence.
The hypothesis.
The hypothesis that disorder perpetuates further disorder is known as the broken window theory. It is thought that removing broken windows, graffiti, litter, and other signs of disorder removes an important trigger for further disorder.
This theory was applied by Mayor Rudolph Giuliani and Police Department Commissioner Bill Bratton (New York City), who relentlessly pursued petty criminal offenders, such as aggressive "squeegeemen." Although crime rates did drop in New York City over their tenure, the underlying cause(s) for this drop in crime are passionately disputed.
The broken window theory has since been applied elsewhere. However, it remains controversial, because there is no set definition of "disorder," and the hypothesis lacks rigorous experimental verification.
Defining disorder.
The scientists first needed to define disorder. They define disorder in relation to opposing social norms.
Social norms refer to the perception of common approval or disapproval of a particular behavior in general (e.g., the concept of not littering) or one common in a certain surrounding (e.g., littering in an already littered setting).
These two types of social norms are not necessarily in agreement. For example, while littering may be frowned upon, there may be a lot of litter in a particular location.
The scientists define disorder as a conflict between these two types of social norms. Armed with this definition, they then set out to determine how social behavior is influenced by a particular setting.
Testing the spread of disorder.
The scientists wanted to test the broken window theory, i.e., whether a disordered setting promotes disorder, even beyond the violation of simple social norms. Specifically, they wanted to test whether observing inappropriate behavior leads people to disregard considerations of appropriate behavior in favor of other considerations, such as self-gratification and resource acquisition.
They devised six experiments to test this hypothesis. Each experiment was performed in ordinary public spaces, and general conditions (such as time of day) were kept as consistent as possible.
An individual was placed out of sight to witness and record disorder violations. The disorder was obvious in each case.
Violation of general social norms.
The scientists wished to test whether the presence of graffiti encouraged people to litter.
Two alleys were chosen. One was clean of graffiti, and one was not.
A sign that said "littering" was prominently placed in front of both walls. Additionally, a flyer was attached to the handlebars of each bicycle in the alley, in such a way that it would be difficult to ride the bicycle with the flier left on.
The scientists defined littering as either throwing the flyer on the ground or placing it on another bicycle. There were 154 total participants.
In the alley lacking graffiti (ordered scenario), 33% of the participants littered. In contrast, in the alley with graffiti (disordered scenario), 69% of the participants littered.
These results cannot be explained by participant guesswork on law enforcement. Littering is generally ignored by the police in Groningen; graffiti is not.
Disorder (graffiti) promoted further disorder (littering).
Violation of police-enforced and private laws.
The scientists next wished to test whether a violation of either police-enforced or private laws encouraged people to either trespass or litter.
In one experiment, two signs were placed in front of a slightly open gate in a parking lot. One sign said to not chain bicycles to the fence, and the other sign said to not trespass by entering the gate (to instead access the parking lot via a 200 meter detour).
In the ordered scenario, four bicycles were placed 1 meter in front of the fence. In the disordered scenario, four bicycles were clearly locked to the fence.
There were 93 total participants. A group of people approaching the gate was defined as one participant.
When the bicycles were placed by the fence properly (ordered scenario), 27% of the participants walked (trespassed) through the gate. In contrast, when the bicycles were locked to the fence (disordered scenario), 82% of the participants walked (trespassed) through the gate.
Similar results were observed from two more experiments that tested people's willingness to litter. One involved misplaced supermarket grocery carts, and the other involved the sound of illegal fireworks.
In the former, of 120 total participants, 30% littered in the ordered scenario, compared to 58% in the disordered scenario. In the latter, of 96 total participants, 52% littered in the ordered scenario, compared to 80% in the disordered scenario.
Disorder promoted further disorder.
Stealing: A more serious offense.
So far, the scientists had demonstrated that an obvious petty violation of the law encouraged further petty violations of the law. They next wanted to test whether the presence of graffiti or litter encouraged people to steal.
In both of these experiments, a 5-euro note was placed hanging out of an envelope, itself sticking out of a mailbox. Would people swipe the money?
In one experiment, the mailbox was covered in graffiti, but the ground in front of the mailbox was clean (60 participants). In the other experiment, the mailbox was clean, but the ground in front of the mailbox was littered (72 participants).
In the former, 13% of the participants stole the money in the ordered scenario (no graffiti or litter), while 27% of the participants stole the money in the disordered scenario (graffiti).
In the latter, using the same baseline (13% steaing in the ordered scenario), 25% of the participants stole the money in the disordered scenario (litter).
Similarly to the original experiments, in which graffiti was shown to induce littering, these results cannot be explained by participant guesswork on law enforcement. Littering is generally ignored by the police in Groningen; stealing is not.
Disorder (graffiti or littering) promoted further disorder (stealing).
Modifying public behavior.
These experiments clearly demonstrate that negative social actions encourage others to act inappropriately, even on an escalating level. The obvious message is that thorough enforcement of social norms and laws may be of use to hinder inappropriate behavior by the public.
One should not take away the message that police must, or even should, take draconian actions to enforce "social order." In contrast, these experiments provide public servants with an easy method of controlling petty crime, by simply cleaning up the neighborhood and gently enforcing minor laws.
for more information:
Keizer, K.; Lindenderg, S.; Steg, L.
The spreading of disorder.
Science 2008, 322, 1681-1685.