Tuesday, May 12, 2015

awesome broken windows theory tests

This conference on "social norms and institutions", as you might expect, is quite cross-disciplinary. I'm not sure what the breakdown is, but there are plenty of behavioral economists, sociologists, psychologists, and even law professors and political scientists. So, I'm collecting quite a list of interesting new sources from lectures and conversations with these non-economists.

The most fun, and incredible, set of experiments I've learned about are the ones run by Siegwart Lindenberg and Linda Steg and colleagues at Groningen University. Despite having an unusually high prior*, I'm honestly stunned by their results, both in terms of the sheer size of the effects they're finding, and the stability of those large effects across a great number of slightly different situations.

They're studying, essentially, the broken windows theory. This theory hypothesizes that if there is evidence of some law/norm breaking behavior, that will cause people to break other laws/norms at a higher rate.** This is not due to inferences about levels of enforcement, because the findings are just as strong in purely normative (prescriptive, in addition to proscriptive) settings. In a world of marginally statistically significant results, it's a thrill to see such a long list of replications with huge and extremely statistically significant findings.
  1. Bikes are parked in a row next to a fence with a conspicuous "no graffiti" sign, and flyers are attached to each bicycle such that they must be removed to use the bike. If no graffiti is on the fence, 33% of subjects will litter their flyers. If graffiti is on the fence, 69% will. This was so surprising that a news station paid the researchers to replicate the study while they watched from rented rooms looking down on the area. The finding replicated very closely, and now the Netherlands requires immediate removal of graffiti.
  2. A temporary fence is set up around a parking lot. Two police ordinance signs on the gate state "no trespassing" and "no locking bikes to fence". People were directed 200 meters around to an alternative entrance, but the gate was left about 50cm ajar. If four bikes nearby were not locked to the fence, 27% of people squeezed through the gap in the main gate. If the four bikes were locked to the fence, 82% did.
  3. In a grocery store parking lot, a sign states "please return your shopping carts", and flyers are left under the driver-side windshield wipers on cars in the lot such that people had to remove them to safely drive away. When no stray carts were left in the lot, 30% of drivers littered their flyers. When several carts were improperly left in the lot, 58% of drivers littered.
  4. Bikes parked in a shed have flyers attached to them as in example 1. In the control condition, 52% of subjects littered their flyer. If fireworks were set off, within earshot but out of sight, which is a well-known offense prior to December 31 in the Netherlands, 80% littered.
  5. An envelope is left partially hanging out of a mailbox and visibly has a 5 Euro note inside, showing through a window in the envelope. In the control condition, 13% of people who passed the mailbox on foot stole the envelope. If the mailbox was covered with graffiti, 27% stole the envelope. If the mailbox was not covered in graffiti but litter was on the ground next to the mailbox, 25% stole the envelope.
  6. A stamped addressed envelope is on the ground next to a mailbox. In the control condition, 24% of passersby put the envelope in the mailbox. If bags of garbage are on the ground nearby (illegal in the Netherlands), 10% did.
  7. A bike is on the ground in an alley, having apparently accidentally fallen off its stand. If passersby have just entered the alley from an empty, clean street, 20% of individuals and 27% of groups right the bicycle. If garbage bags had been left on the street, then 6% of individuals and 5% of groups did so. If prior to entering the alley, passersby passed by someone who dropped an aluminum can and then picked it back up, 34% of individuals and 35% of groups picked up the bike.
  8. A person on the sidewalk accidentally drops some oranges just before meeting another pedestrian. Normally, 40% of passersby help the stranger pick up their oranges. If approximately 20 yards earlier, the passersby had witnessed someone drop an aluminum can and pick it up back up, 64% will help the stranger. If 20 yards earlier, the passerby had witnessed someone (a private citizen) sweeping the sidewalk, 82% helped the stranger.
  9. I can't find the numbers for this one, but in a mall where you have to walk down a hallway to get to a smoking zone, a certain percentage of people will start smoking before they reach the zone. If a group of typical looking Germans are standing around smoking prior to the zone, though, more passersby will light up early. If a group of goth teens are smoking prior to the zone, though, a higher than normal percentage of passersby will wait until they get to the smoking zone to light up.
Amazing. And while each individual study has many issues with interpretation and is targetting a different nuance of the phenomenon, the evidence from all 9 considered together is undeniably striking.

References: 1-8 come from here and here.


* Perceived unusuality is based on my reading of the literature (see next footnote). I've always been sure (without solid evidence) that the mechanism must be quite important.
** This motivated a famous crackdown on petty crime in NYC, which did undergo a drastic reduction in crime, but causality has not been convincingly established and the theory remains controversial.


Wanda said...

In the New York City case, people have alleged that "broken windows" policing led to more police harassment of minority citizens. If you ask the police to crack down on petty crime, and many police are much more inclined to believe that minority citizens are petty criminals, then it makes sense to me that disproportionate numbers of minority citizens are going be targeted for "loitering" when they're waiting on the sidewalk for a friend, "trespassing" when they're walking in their own neighborhoods, or for drug searches when they're just existing. Then, higher numbers of minorities end up in the system such offenses, which helps perpetuates the stereotypes. This suggests such "broken windows" policies much be implemented carefully.

Vera L. te Velde said...

I couldn't agree more. Police abuse in NYC is completely out of control; that was the single worst aspect of living there even as a white woman. I've never had a single positive interaction with the NYPD.

Anonymous said...

I'd like to see some other social norms testing: will the presence of litter or graffiti make it more likely that an officer will illegally harass a young black male? What if the officer just walked past someone who was sweeping the sidewalk?

pithom said...

Are non-Asian minority citizens in the U.S. disproportionately petty criminals? You certainly haven't shown they aren't. Stereotypes don't emerge out of nowhere (though they may be tainted by common cognitive biases).

And it's not just NYC. Much of the South and Appalachia also has such corrupt police forces (indeed, all U.S. states have them to some degree, but there are regional variations in frequency).

And, BTW, the safest nation in Africa also has the highest incarceration rate.

Anonymous said...

You said: " I've never had a single positive interaction with the NYPD."

This says more about you than the NYPD.

Anonymous said...

This is all neat, but the police can't seem to process information like this without using it as reason to be abusive. We're a long way from getting those idiots in blue to think critically about anything so examples like this only end up becoming perverted into something oppressive.

Anonymous said...

you're stereotyping police just like you claim they are stereotyping minorities. While in a police force of some 30K+ in NYC there are bad apples, the fact that murders, the most heinous crime, has been cut so far is a testimony to how this kind of policing can work. Once crime is down, it makes sense to modulate your practices carefully. By the way, a black murder rate 8-10 times higher than the white murder rate suggests that stereotyping as you seem to define it may not be happening as much as you think.

Vera L. te Velde said...

oh how I wish that were true :)

Vera L. te Velde said...

I don't have anything to say about stereotyping in response to all these comments, but I'm glad police abuse in general has become such a hot topic. As a (positive) scientist I feel that the normative conclusions are not immediate from these studies, but they are fascinating nonetheless.

Anonymous said...

I wonder how these results hold up regarding violent crime.

Anonymous said...

Do you have any concept of the diff between some short term artificial tests and the real world ?
oh, wait, you are an economist...

Do you understand that science is about explanations that are solid ?
with tests that rule out alternatives ?
oh, wait, you are an economist

A stamped addressed envelope is on the ground next to a mailbox. In the control condition, 24% of passersby put the envelope in the mailbox. If bags of garbage are on the ground nearby (illegal in the Netherlands), 10% did.

you really think this is a test of broken windows theory ?
maybe the garbage is smelly or looks bad or makes people think the paper is dirty

Vera L. te Velde said...

Me too - I know the authors are aware that they haven't proven anything about major crimes, and I hope they've got something up their sleeves to address it a little more closely.

Vera L. te Velde said...

Thank you, proud to be one! Solid empirical proof is really hard to generate and anything bigger than baby steps complicates the interpretation.

Anonymous said...

The results might hold, but I think (hope?) that littering and mugging are different enough that graffiti on the wall might be enough to encourage the first, but not the second.

Drew said...

What if the decline in violent crime was similar in other locations that did not have the same type of policing activity? Would that suggest that the change in policing in NY was coincidental rather than causative?

Oh wait, that's exactly what happened. http://www.motherjones.com/kevin-drum/2014/12/broken-windows-broken-theory-crime

ghengis blond said...

quoting from the pop literature

"they get at u u get at them or u don't mean nothing"

"it been more than 3 weeks and we don't see no type of getback. what type of bs is that? your crippin is wack"

tests for veracity of broken noses theory will likely b confused by strong complementary effects from the need for criminals to defend themselves from one another via signaling and direct actions against enemies

I'm a cop in a way less violent place than 80s NYC. We like "quality of life" policing not only for the apparent broken windows effects, but also because we get to build criminal records against known lunatics so that, failing conviction for serious crimes that r difficult or expensive to prove, we can compile pettier offenses and imprison them, because we get to cultivate more CIs in neighborhoods where police cooperation is unlikely without strong incentives, and because we r strongly prejudiced against risk-tolerant young men

Anonymous said...

In New York when testing the broken window theory, were any of the broken windows actually repaired?

Patrice Ayme said...

One is either moral, or one is not so: at least, this is what the Ancient Greeks and Romans thought. The very idea of morals recognizes that lack thereof will lead to the contagion of immorality. Thus that immorality propagates like a plague has been recognized for more than 26 centuries. Then the Athenian legislator Draco set-up a legal system which punished most offenses (such as stealing a cabbage) with the death penalty.

The notion can be fruitfully used today: minor offenders can be arrested and their DNA can be documented. As big offenders tend to start as small offenders (that's the point when they become immoral), as they commit a big crime, their DNA collected during their previous small crime will often allow to identify them. Hence the increasingly fast and accurate detection of big crimes nowadays. This is discouraging for would-be big time criminals, so the big time crime rate is plummeting.

However, internationally the effect can play the other way: when states see that aggression by other states is not punished, that immoral behavior is in plain sight, and nobody does anything about it, then immoral states so far rather innocuous tend to join in mayhem. This is why, in the 1930s, war and bad actions by states spread around the planet in a few years.

More generally this is why one war does not generally happen alone, and why tolerated international abuse tend to lead to apparently unrelated wars in the same time frame.

Hence a war such as the one in Syria has a general deleterious moral effect for all those who hear about it, or watch it, and learn to tolerate it.

Patrice Ayme

Drew said...

You just presented Draco as an example of morality to emulate. Frightening.

Patrice Ayme said...

If I had, presented Draco's morality as worth "emulating", it would be frightening. But I did not. It's all in your (frightening?) mind.

It goes without saying that I would rather "emulate" Solon (who changed Draco's system to something in usage today, in the West and Islamist countries; although Solon kept the death penalty for homicide, as long as the victim's family agreed).

Steve Erickson said...

I am looking at this not in terms of urban violent crime, but in terms of violation of environmental and land use law. Its very common for well connected developers and corporations to pretty much ignore land use and worker safety laws and if they are actually charged with a violation, the penalty amounts to a slap on the wrist. In the US, the tax system would seem to encourage this behavior, ala broken windows, by allowing deduction from taxes of fines and penalties for environmental and safety violations. In strictly economic terms, the penalties simply become a cost of doing business. But in sociopolitical terms, this situation would seem to lead to precisely the behavior predicted by the broken windows theory.

The above anecdotal but widely held observation might provide a real world situation for testing the broken windows theory at a meta scale. Behavior could be compared within the same industry between geographic regions based on the degree, severity, and economic effect of penalties for all violations. Would those industries where there is sustained enforcement for "minor" violations have a lower rate of "major" violation than those where there is little overall enforcement or enforcement is limited to major violations?

I'm a mere botanist / ecologist / barnyard environmental attorney. Have any social science types done this or something similar. Do these organizations behave like individual or small groups of people ala broken windows? If so, this would seriously call into question the current "fad" holding that the only way to change such behavior is by education and subsidy.

Drew said...

"Thus that immorality propagates like a plague has been recognized for more than 26 centuries.


The notion can be fruitfully used today ..."

First line says they were right. Second line says we can apply that knowledge in a similar way.

Try as you might to walk it back, those were your words.

jo said...

Even if non - Asian minority citizens are disproportionately petty criminals, that would not (in my opinion) justify harassing a random, innocent non - Asian minority citizen.

Anonymous said...

The natural experiment for violent misbehavior is right in front of our faces: look at the relationship between police behavior and the perceived level of "upkeep" in an area. Where there are more "Broken Windows," the theory should predict greater lawlessness, including police misbehavior.

Nobody would be shocked if police brutality were less common in a well-kept suburb. And I think many people tolerate greater police brutality if an area is viewed as rundown.

What is the relationship between police misbehavior and the precinct-level crime rate? Anecdotally, police in a high-crime area are more prone to abuse contacts than police in a low crime area.

Combine "Broken Windows" with the known implicit bias against dark-skinned people, who are viewed with greater suspicion by police. So "Broken Windows" would predict that implicit bias should cause greater misbehavior by police, in areas where there are more dark-skinned people.

One could even speculate that major police misbehavior is more common on forces where minor misbehavior ("littering") is routine.

If "Broken Windows" has a bearing on criminal behavior by non-police, then it should also predict misbehavior by the police.

Patrice Ayme said...

Who are those "they" you say I think were right? The entire class of early Western law givers, including Solon (who removed the death penalty for all, but homicide, and then only in special circumstances). The ones, all the way back then, who recognized immorality was contagious, which is the point of the Original Post.

So I walk back nothing. On the other hand, I think that political correctness aspersion by imputation of statements one in no way made, is, at the very least, not nice.