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The psychology of littering

Posted by Robin Abrahams  August 26, 2008 07:55 AM

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A guest post from Catherine Caldwell-Harris, aka the Traveling Psychologist:

I carried my laptop and canvas chair to my usual lookout spot atop the beautiful Chestnut Hill reservoir at Cleveland Circle and was startled to find I would not have the rocks and grass to myself: I would share then with silvery beer cans, cardboard beer boxes, and cigarette buts and Dunkin' Donut bags.


Of course -- it's kids. Kids come up after dark to smoke, drink and litter. The joggers who loop around the majestic reservoir 30 feet below are probably tree huggers who would pack in, pack out and carry plastic bags for dog pick-up.

What do you do when someone trashes your nature spot, readers? Take a snapshot and post it with an angry note? Start cleaning it up with an aggrieved air so that the joggers feel bad and stop to help? Stake out the spot in the next nights so you can give the drunken offenders a piece of your mind?

Why do people litter, anyway?

It turns out that people -- joggers, kids, hikers, homeless - don't litter just because they're lazy and don't care. My box-strewn spot is what social psychologist Robert Cialdini would have predicted based on the "before" picture. The past decades of late night reservoir viewing have left the lookup with broken glass and small detritus. In "Crafting Normative Messages to Protect the Environment," Cialdini noted that people litter in an already littered environment, and they refrain from littering in a pristine environment. Littering happens when plastic bags, cans and broken glass inform us that this is a place where the normative -- usual, expected -- practice is to litter. A pristine environment sends the message that we would be socially out of step if we littered.

An example of people's sensitivity to social norms comes form an ingenious study conducted at Arizona's Petrified Forest National Park, which was trying to keep visitors from taking fossilized wood from park paths. Large amounts of wood were being pocketed by visitors despite signs reading: "Your heritage is being vandalized every day by theft losses of petrified wood of 14 tons a year, mostly a small piece at a time." Despite these signs -- or because of?

Cialdini and colleagues reasoned that the signs were informing readers, "Lots of people steal wood (and so you may as well do what everyone else does)." Collaborating with park officials, they placed secretly marked pieces of petrified wood along the paths, and then varied the warning signs. When signs mentioned the number of others who had stolen wood, theft of the marked fossilized pieces were 5 times higher than when signs simply told visitors not to remove the petrified wood from the park.

According to these environmentally minded social psychologists, when we stoop down to pick up someone else's litter, we're doing a lot more than just cleaning up after a prior jerk or providing a service to the unknown next viewers on the scene: We're sending the message to future joggers, walkers, and drinkers that this is a litter-free place.

This research explains why smokers will not put their butts in a plastic bag and take them to a trash can until they see most other smokers doing this.

A further implication of the social psychology research is that when we see others actually cleaning up litter, then we take in the message that cleaning up litter is socially desirable. But Americans may not draw this conclusion, since altruistically cleaning up litter isn't frequently done - or is it? If you saw someone cleaning up litter would you think:

(a) "That is so cool, I guess I should clean up litter I see too."
(b) "It's good someone is actually picking up their own litter."
(c) "Park employees are finally doing their job."
(d) "That's a homeless/crazy person who has a hoarding disorder" (or: is looking for bottles with MA deposit, or: cigarette buts with a pinch of tobacco left).

This blog is not written or edited by or the Boston Globe.
The author is solely responsible for the content.

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6 comments so far...
  1. I would think "A". I also think you have to add in cultural differences that seem to me have something to do with geography. I grew up in a rural area with lots of pristine forest and the message of not littering was as common as not lying or stealing, it was simply part of our culture, as ingrained in us as the air we breathed. I am raising my own kids in a city environment and it seems to me that this message is simply not a part of the landscape. Kids aren't taught not to litter here.

    Posted by Marianne August 26, 08 09:01 AM
  1. Probably "B".

    I've cut my hand on broken glass picking up other people's litter before, so it's cut back my tendency to do so.

    Posted by Danielle D. August 26, 08 09:34 AM
  1. I've probably thought "all of the above" at various times in life. I remember one day on the NYC subway I saw an older gentleman picking up all the litter near him, and I thought he was nutso. I knew for a fact it was not his litter, since it was there before I got there and I was there before he got there.

    In fact my one complaint about the subways and the Metro-North railroad is that there is not trashcans on board. NJ Transit trains have trash receptacles on board, and people are more likely to throw their garbage away because of it.

    Posted by Veronica August 26, 08 09:45 PM
  1. I would do A, and feel badly that I don't do it more often. I've always told myself when I go walking with my son to bring a plastic bag along. It's amazing how if I clean up the litter in the street and yard how much longer it takes to build up. Litter invites litter is a true phenomenon.

    Posted by Sally August 27, 08 07:23 AM
  1. I have two comments:

    1)Someone should send that study to the MBTA officials because the signs we have now are read more as: "You're paying to clean this up, so you might as well make sure your money is used well." Instead of "Don't litter on the train."

    2) Since I have a dog and tend to walk with plastic bags whenever he's with me, I've taken to picking up trash along the beach in Maine. It's amazing how many people will dump stuff (although York Beach does tend to be super clean when compared to other places). One day there were no fewer than 4 folks with metal detectors, each of which had just covered an area with a prominent beer can (which should have alerted them to its presence) and each of them ignored it. Gah. I picked it up.

    Posted by Alyson August 27, 08 11:55 AM
  1. This is usually looked at in terms of the Broken Window Syndrome. That's how I've always looked at picking up trash, anyway.

    Ever since my brother mentioned it to me when I was quite young i've been tempted to apply BWS really extensively. Gladwell's 'The Tipping Point' convinced me to go ahead and do that with gusto.

    Explaining it more directly in terms of the socially acceptability aspect as you have makes a better intuitive case for it than the traditional description.

    Posted by Luca Masters August 31, 08 10:26 PM
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Welcome to Miss Conduct’s blog, a place where the popular Boston Globe Magazine columnist Robin Abrahams and her readers share etiquette tips, unravel social conundrums, and gossip about social behavior in pop culture and the news. Have a question of your own? Ask Robin using this form or by emailing her at

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Robin Abrahamswrites the weekly "Miss Conduct" column for The Boston Globe Magazine and is the author of Miss Conduct's Mind over Manners. Robin has a PhD in psychology from Boston University and also works as a research associate at Harvard Business School. Her column is informed by her experience as a theater publicist, organizational-change communications manager, editor, stand-up comedian, and professor of psychology and English. She lives in Cambridge with her husband Marc Abrahams, the founder of the Ig Nobel Prizes, and their socially challenged but charismatic dog, Milo.

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