The Effect of Signs & Incentives on Littering

I hate littering.

It’s inconsiderate.

And it’s a form of laziness I just can’t stand.

  • There are the intentional litterers: the gum chewers who spit their gum on the sidewalk, the smokers who flick their cigarette butts out their windows, the dog owners who leave their dogs’ feces on the sidewalk or in a neighbor’s yard.
  • And there are the “accidental” litterers: the pickup driver who throws trash in his truck bed and lets it get swept out while he drives down the Interstate, the homeowner who sets out an overflowing trash can without a lid on a windy day.

Whether it’s intentional or “accidental” littering, I hate it.

(A note for the global warmists: If we can’t even get people to properly dispose of their own waste, how in the world are we going to get them to reduce their “carbon footprint”?)

In spite of the near impossibility of changing people’s behavior, let’s take a shot anyway.

We want to make sure people properly dispose of their trash instead of tossing it on the ground. What do we do?

Do we, for example, put up a sign that says “Do Not Litter”?

The Harvard Business Review makes the observation that No-Littering Signs Have the Opposite Effect If There’s Already Litter:

When an anti-littering sign appeared on an alley wall, the proportion of people who littered there declined from 47% to 39% if the alley was clean — but rose from 61% to 70% if the alley was already strewn with soda cans and candy wrappers, say Kees Keizer, Siegwart Lindenberg, and Linda Steg of the University of Groningen in the Netherlands. A prohibition sign can become counterproductive if people see that its instructions have already been ignored, the researchers say.

While this bit of information is interesting, I wonder what its implications are.

A sign that says “Do Not Litter” is subconsciously telling people to litter. Can’t we do better than that? After all, what is a sign but a short-copy opportunity to influence behavior?

A Better Sign to Stop Littering

Here’s an idea… What if we posted signs with a positively phrased message? For example: “Keep This City Clean.” Or, even better, imply ownership: “Keep Our City Clean.”

Then make the signs specific to the place:

  • “Keep Our Park Clean”
  • “Keep Our Neighborhood Clean”
  • “Keep Our Block Clean”
  • “Keep Our Sidewalks Clean”

I bet this wording would persuade people to be more intentional about properly disposing their trash. But let’s take it to the next level.

Scrutiny has a powerful effect on human beings and their behavior. In Superfreakonomics, Levitt and Dubner recount a study that was conducted by a professor in England.

Our behavior can be changed by even subtler levels of scrutiny. At the University of Newcastle upon Tyne in England, a psychology professor named Melissa Bateson surreptitiously ran an experiment in her own department’s break room. Customarily, faculty members paid for coffee and other drinks by dropping money into an “honesty box.” Each week, Bateson posted a new price list. The prices never changed, but the small photograph atop the list did. On odd weeks, there was a picture of flowers; on even weeks, a pair of human eyes. When the eyes were watching, Bateson’s colleagues left nearly three times as much money in the honesty box.

Now imagine a sign posted in the picnic area of a park. This sign has a pair of wide-open eyes at the top. Underneath, it says:

Keep Our Park Clean.
People Are Watching.

I bet this sign would be FAR more effective than an ordinary “Do Not Litter” sign.

Of course, not all littering problems can be improved or solved by better signage.

Smokers Love to Litter

Why do smokers think they get a free pass when it comes to littering?

If a smoker is driving a car, and she finishes a cigarette, ten bucks says that cigarette butt gets tossed out the window.

I can’t stand it when I see a smoker throwing a glowing butt out the window. It takes all my self-control to not lay on my car horn and flash my brights.

I once spent an afternoon doing road clean-up when I worked for Merrill Lynch. There were plenty of random car parts (broken hubcaps, bolts, etc.), plus an assortment of fast-food wrappers and soda cans.

But can you guess the #1 trash item in terms of sheer volume? Cigarette butts! I found thousands of them along the side of the road. They’re difficult to clean up, they make your hands stink, and they never biodegrade.

Now, getting people to throw away their trash at a park is hard enough. But getting smokers to hold onto their cigarette butts is magnitudes more difficult.

In this case, we can’t really use signs. Most smokers litter while driving their cars. And they’re often alone while driving, so it would be difficult to use peer pressure to keep them from littering.

What else could we do?

People Respond to Incentives

In the introduction to Superfreakonomics, Levitt and Dubner point out that:

People respond to incentives. If you wanted to get more expansive, you might say this: People respond to incentives, although not necessarily in ways that are predictable or manifest. Therefore, one of the most powerful laws in the universe is the law of unintended consequences.

With that in mind, what about this…

Let’s provide an incentive to throw away cigarette butts. For every cigarette butt you bring to a central disposal location, you get a nickel. Bring back 20 butts, you get a dollar. Bring back 200, you get $10.

It would be very simple to build this incentive into the price of a pack of cigarettes.

Overnight, you’d have thousands of smokers across the country who would start keeping their cigarette butts and redeeming them for cash. And you’d have a whole army of young people hitting the streets to pick up “nickels.”

I believe in one month’s time, cigarette butts would rarely be thrown out car windows. And the littering problem would be greatly diminished.

What Does Littering Have to Do with Marketing?

If you’re in the business of persuading people, then I hope you find this mental exercise stimulating. How do you persuade people? How do you change their behavior?

It matters little whether we’re trying to get them to stop littering or buy your product. The language we use… and the incentives we offer… have a profound effect on the outcome.

-Ryan M. Healy

Ryan M. Healy

Ryan Healy is a financial copywriter and the author of Speed Writing for Nonfiction Writers. Since 2002, he has worked with scores of clients, including Agora Financial, Lombardi Publishing, and Contrarian Profits. He writes a popular blog about copywriting, advertising, and business growth, has been featured in publications like Feed Front magazine, and has been published on sites like,, and

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