Garbage and the Herd Mentality

(Photo: Kerry Murphy)

In our recent podcast “Riding the Herd Mentality,” we discussed how the actions of people around you significantly affects your behavior. A new paper studies garbage and litterers, and whether more garbage begets more garbage. Researchers Robert Dur and Ben Vollaard collected data for three months in a densely populated residential area in Rotterdam for some 4,000 households. The abstract:

Field-experimental studies have shown that people litter more in more littered environments. Inspired by these findings, many cities around the world have adopted policies to quickly remove litter. While such policies may avoid that people follow the bad example of litterers, they may also invite free-riding on public cleaning services. This paper reports the results of a natural field experiment where, in a randomly assigned part of a residential area, the frequency of cleaning was reduced from daily to twice a week during a three-month period. Using high-frequency data on litter at treated and control locations before, during, and after the experiment, we find strong evidence that litter begets litter. However, we also find evidence that some people start to clean up after themselves when public cleaning services are diminished.

They found that in the experimental treatment areas where garbage collection services were reduced, the amount of litter increased by almost 50 percent. However, residents in these areas also considered alternatives to waiting for garbage collection: donating old household items. Dur and Vollaard write: “Overall, our findings suggest that the provision of public cleaning services crowds in private contributions to a clean environment of some people, even in the longer term, but crowds out private contributions of others, with the former effect dominating the latter.”


I guess this raises two questions: one, is litter a problem? That is, do the people who live and travel in the littered areas consider litter a problem? If no, then the study is meaningless. If yes, that would lead to the second question: were the streets cleaner when government services were provided?

Well, I read the report and the first question is answered yes in the report. The second question is never really flat-out answered; which is odd because it would seem simple to determine whether some area is cleaner or not. I do thin that 3 months is way too short a period of time to measure such results given the lifetime people have to develop habits.


Depends on the litter, no? Discarded beverage and food attracts all kinds of pests like birds, insects and vermin. It's not as though we strictly have a "clean litter" problem.


wonder if (marketed) fines for littering work

Mike Wyman

Is this nothing more than the 30-year-old Broken Windows Theory? (

ginardo napoli

Thanks for link Mike. The "broken windows theory" relates to the idea that changing the normative background (fixing the broken windows) reduces petty crime. There is evidence that kids growing up in horrid environments can be stunted, but the reasons that people do petty crime can also be unrelated to the upkeep of the neighborhood. The criticisms of the BWT have a little merit, but that's because you can't strip the criminality from the various constituents that produce criminality so neatly. Just keep the windows fixed and crime will go away. Yea, right!

In this post however we are talking about whether changing the regularity of garbage collection influences or "crowds out" individual actions to keep the neighborhood clean. Will a lot of garbage cause people to litter more or will it give incentives for people to act on behalf of the slobs who don't clean up after themselves.

This is like saying that some people who drive will yield to a car waiting to turn on a busy street, and others will not. Will living in a region of more busy streets cause people to be less willing to yield?

It's an interesting point.


ginardo napoli

Mind you too, that we are talking about a society of people who travel to and fro from cars, speak to others on portable phones, and watch a two dimensional object with high frequency when they aren't working their jobs to earn money to be able to feed themselves, make rent, and pay the utility bills. We aren't talking about people in the 1850's or 1900's or 1700's who walked or rode a horse everywhere or travelled in common by train or carriage, and communication and public discourse was common, long, and personable.

ginardo napoli

Beware of the phrase "Overall, our findings suggest" .

This phrase usually (but not always) indicates the potential of drawing the wrong (usually preconceived) conclusions because such events are witnessed over too short a period of time to become significant.

What people do over a three month period is much different then over a two or three year period, or a decade (or even a generation) to really draw any valid social conclusions. The initial reaction might be only an interim period, and therefore not indicative of the long term consequences and behaviors. Despite the scholastic disclaimer: "Using high-frequency data on litter at treated and control locations before, during, and after the experiment" you are drawing a lot of conclusions from the minor change in one social service in one area and one social community.

It is also difficult to see the events out of the contemporary context over a three month interim. (Was that 3-month hit song indicative of long-term success, or just a momentary blip that will be forgotten 2 years hence?)

Although it might be true that some persons clean-up after themselves, the fact is that other people do not. Like Duh....Did you really need a 3 month experiment to tell you that? Some people are organized, methodical in their cleanly habits (god bless) ; others are slobs. And when it comes to taking out or picking up garbage, the slobs will create a burden on those who decide to take community action. In this sector, it is too important that everyone maintain some level of cleanliness, to put up with the irresponsibility of some.

Honestly, that last paragraph is a lot of phooey. How do you both "crowd in" AND "crowd out" "private contributions" ? I know you mean "push in" and "pull in" but this sounds like having your cake and eating it too. Either way private contributions are the measuring stick.

The more important question to my eyes is this: what exactly does "crowd in" and "crowd out" have to do with how people decide to act in response to a change in their garbage management environment? Is this statement actually attributing the agent doing the "crowding" that of public garbage collection?

Strong evidence that litter begets litter is common sense. When society's occupants see a community degraded by regular garbage, they concern themselves less and see the garbage as part of the normative environment. Duh? Go back to 1800's and earlier. Research the history.

We collect garbage because it is the cheapest, most effective method of preventing disease and plague outbreaks. One of the reasons the Bubonic plague hit Europe so often and so hard from 1300 to 1500 (more then 50% decrease in population) was because of the raw sewage and garbage that were commonly in every European city and town. In the 1700s and earlier people would drink beer because the water was safer than the available water sources because of the poor sewage and garbage disposal.

"Donating old household items" will never be an alternative to regular garbage collection. (Are you serious?) Even if the people in this "study" were said to "consider" it. That doesn't mean it will work, not have consequences, or that the persons actually "act" on what they are "considering". People "consider" a lot of actions, especially in response to a change to their normal environment. The predictive value of all these considerations is however not useful or even consistent, because people don't act in a way consistent with the things they "consider".

Lucky for us, we don't have to "predict"; we have history (past and present) as a strong indication of what happens when normal communal functions become dependent upon individual discretion. Go to the slums of Rio de Janeiro and Mexico City.

All an all, I really don't see the point of the post, or the article. If you want to throw out preconceived ideas about human behavior, there are better and more honest vehicles for that endeavor then pretending a poor empirical study supports you own views.



There is a great book by Bill Buford called Among the Thugs which discusses crowd violence. For those interested in Herd Mentalilty this book could give further insight. It has been awhile since I have read the book, but the author gives compelling examples of how ordinary English soccer fans turn into hooligans partly because of the act of acting collectively.


I used to live in a storefront apartment on 4th Ave. in Brooklyn, where I was responsible for keeping the sidewalk clean (the Sanitation Police could ticket the landlord) and there was lots of foot traffic headed to the subway. Over the years, I noticed that if there was ONE piece of litter in front of my place in the morning it would soon be joined by a whole pile of trash. However, if I picked up that one piece of litter first thing, then the sidewalk would remain clear. People who saw one piece of litter there seemed to feel it was okay to add to it. I did and do think it's the Broken Windows Theory.

Of course, the amount of litter increased exponentially when the Sanitation Dept. took away the litter barrel at the corner.

Malice in Wonderland

But at least those pesky terrorists are no longer using the litter barrel to store their IEDs right? The world is saved once again by forward thinking bureaucrats!


If people see that others will pick up after them, then they will continue to litter. I see this at my school every day. Trash cans can be 5 feet away and the kids will just get up and leave their trash on the table; knowing that the adults would pick up the trash.