Nudging to Fight Littering

This brief article provides a couple of well-known examples on how to use nudges in the domain of littering. Two cases, one from Europe and one from the States, illustrate how insights from behavioural economics can be helpful to implement successful campaigns against littering.

Littering Prevention in Copenhaghen


In 2011 a team from Roskilde University (Denmark) carried out an experiment in the streets of Copenhaghen, to test a nudge to prevent littering on the streets. First, they handed out candies to people and then counted the number of wrappers left  in the garbage cans, on the street, and in the bycicle baskets. Then, after placing some green footprints on the ground that led to the garbage cans, they repeated the experiment and the counting. With the footprints, as a result the team registered a 46% decrease in the wrappers left on the streets.

The footprints were effective because when we daily rush in the streets, we may be less perceptive of the social environment, so simply making more salient the presence of garbage bins can help people to perform a desirable behaviour. Salience is a nudge employed in choice architecture theory. In the experiment, the footprints act as a cue that subliminally catch our attention directing our way to the bins. Particularly, the intuitive behavioural system called “System 1” is solicited when it sees the footprint, automatically gearing our way to the bin. The footprints have been used in the “Clean Copenhaghen” city campaign, and are widely employed across Denmark.

A Winning Campaign Agaist Littering in Texas


In 1986, Texas launched a very creative campaign to reduce littering on highways. Since then, former campaigns had been ineffective to convince citizens not to leave waste on the roadways. Using in-depth research, the state identified the worst offenders (men aged 18-24) and how best to reach them. Public authorities produced a spot were football stars collected waste and growled ‘Don’t mess with Texas’ (the slogan has the double meaning of “do not dirty Texas” and “do not look for trouble in Texas”).

The behavioural notion behind this idea, is the acknowledgement of the importance of social norms, which also have been identified as a nudge, another ‘tool in the box’. Humans naturally tend to conform and thanks to the social influence of the celebrities in the spots, the slogan became an identity statement, a true cultural phenomenon in Texas. Today is possible to buy any type of “Don’t mess with Texas” gadget: stickers, mugs, t-shirts. The slogan is now known by 95% of population in Texas, and in the first year of the campaign waste decreased of 29%, and of 72% over the first six years.