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Can We Nudge People to Recycle?

Our ‘Living Lab in Looe’ project aims to better understand why plastic is ending up in the Looe River and whether psychologically-smart signs can ‘nudge’ visitors’ behaviour towards better behaviour along the harbour quayside in Looe, Cornwall – turning them away from throwing plastic in the river towards recycling their waste.

The whole idea for the project was inspired by research by J. Cinner in 2018 (1) that found that conservation campaigns often have little effect because they don’t understand what actually drives human behaviour – they focus on changing attitudes through education, but often fail to actually change peoples behaviour. For example its much easier to use an education campaign to get people to think recycling is good, than to actually get them to recycle. Other psychological factors are at play.

To test out new different psychological methods against old methods we created simplified versions of common anti-litter signs and some new signs informed in their design by the modern scientific understanding of our human minds. The visual ‘nudges’ utilised in this study are a series of 7 different types of signs designed to encourage visitors to dispose of their plastic responsibility. All the signs feature a informational/educational message “Litter harms our community and marine life” at the bottom. They were designed in accordance with previous research – which argues plain-English wording with clear iconographic images is most effective (2,3,4).

behaviour change signs

Three of the signs copied the most common strategies of contemporary conservation signs reminding individuals of fines for littering, that the site is part of a conservation area and that Looe is a strong community (See above). The remaining four signs were designed in accordance with our modern understanding of our minds, utilising the effect of various psychological effects. One used observation bias in the form of a watching eye with the wording “You are being watched”. Another used a prescriptive norm in the form of “Be a hero – Recycle” and a icon modelling the desired behaviour. Finally the last two used a positive and negative version of the same descriptive norm “9 out of 10 people use a bin” and “1 out of 10 litter” with icons indicating this.

sustainable tourism
Above you can see the study squares (right) and where the signs were fixed onto the harbour piles (left). The study are and signs were only made possible thanks to our collaborators from the Looe Harbour Commissioners, the Looe Marine Conservation Group and Looe Gifts.


reducing rubbish

Psychological Signs Reduced Plastic Litter

Our experiment results showed a significant reduction in the accumulation of plastic in sites with the observing eye, the prescriptive “Be a Hero – Recycle” norm, positive descriptive “9 out of 10 use a bin” norm, and the conservation salience nudge signs. 

Traditional Signs with Fines and Community Messages had no effect

There was no significant difference between the control sites and sites with signs featuring reminders of community or financial penalties for littering.

Signs Stating that "Some People Litter" actually created more waste!

Signs featuring the negative descriptive norm of “1 out of 10 people litter” actually significantly increased the accumulation of plastic. 


Overall our experiment suggests that behavioural ‘nudge’ signs and targeted salience signs can be powerful tools for encouraging pro-environmental behaviour.

What do Results mean for Future Conservation Campaigns?

Traditional approaches need to change: Traditional fine signs and those leveraging community identity may not be effective in tackling marine plastic. We may need to give up on the idea that messages scaring people with fines or using vague calls to community or national pride actually make any difference on actual behaviour.

Psychological nudging is powerful, in the moment at least: Social influence and targeted salience signs can be powerful tools for encouraging a reduction in plastic waste, though likely have no effect long term. Also this strength comes with a cautionary tale – care must be taken to avoid increasing the salience and perceived social acceptability of negative behaviours. 

Signs work: Well-designed sign interventions therefore can form part of an effective long-term prevention of marine debris, representing easy-wins in the battle against litter and marine plastic debris for local groups and authorities.

The hope is that we can find more effective solutions to the environmental challenges Cornwall and the rest of the world faces. The insights gained will also help any community, business or organisation experiencing environmental problems due to the behaviour of visitors, who are often not invested in the long-term health of the environmental places they visit, helping coastal communities to make signage that is targeted and effective reducing the tide of plastic entering our oceans.

Further Information and References

reducing plastic

Here is the juicy quantitive details for the Box plots above.

(1) Cinner, J. (2018). How behavioural science can help conservation. Science, 362(6417), pp. 889-890

(2) Byerly, H., Balmford, A., Ferraro, P.J., Hammond Wagner, C., Palchak, E., Polasky, S., Ricketts, T.H., Schwartz, A.J. and Fisher, B., 2018. Nudging pro‐environmental behavior: evidence and opportunities. Frontiers in Ecology and the Environment, 16(3), pp.159- 168.

(3) Beretti, A., Figuières, C. and Grolleau, G., 2013. Behavioral innovations: The missing capital in sustainable development?. Ecological Economics, 89, pp.187-195.

(4) Shotton, R., 2018. The Choice Factory: 25 behavioural biases that influence what we buy. Harriman House Limited.

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