Nudges and the climate

13 Apr 2022

Thinking before nudging promotes climate citizenship: Evidence from an experiment in the UK

New research shows that when people are made to think about their behaviour before they are nudged, the effectiveness of nudging increases by 30 percent. The study, to be presented at the annual conference of the Royal Economic Society, uses an online experiment with 3,074 participants in the United Kingdom to evaluate systematically the role of reflection in scaling up climate policies.

The research study is led by Sanchayan Banerjee, along with Matteo M. Galizzi, Peter John, and Susana Mourato. They find that being open and transparent about a nudge does not lead to any backfire effects. They also show that the benefits of reflection are realized only when people are made to think before the nudge, and not after it.

Their research suggests a new form of behaviour change, nudge+, where reflection can significantly increase the traction of nudges. They conclude by showing that engaging in climate-friendly behaviour does not lead to other compensatory behaviour. For example, in the experiment, people who intend to consume low-carbon meals do not decrease their contributions to pro-social charities.

As background, nudges have been increasingly deployed to deliver climate policies in the last decade. A nudge changes the way choices are presented to people, so that they can make better choices for themselves and society. Nudging has been generally successful in steering welfare-improving behaviour, as nudges are simple and cost-effective, and most people tend to like them. But recent evidence shows nudges can be hard to scale up. So, can we use nudges more effectively to solve the big problems of our age, not least climate change?

Two researchers in the team, Banerjee and John (2021), had made a theoretical start by proposing a participatory approach to nudging. Their idea, which they called nudge+, suggested that empowering people to think through the nudge and their behaviour will ultimately increase the effectiveness of the nudge and make it more transparent as a means of behaviour change.

The research team then set out to test this claim rigorously using an experiment. They designed an experimental study where people were asked to place an order for an online meal delivery. The researchers then randomised the way different menus were presented to these participants.

Each randomisation mimicked a particular behavioural public policy. For example, in the baseline, the standard menu included 36 meals. In the green default nudge, the researchers presented participants with a shorter set menu of low-carbon items only, from which they could opt out.

In another “treatment” condition, participants were explicitly told the reasons why this shorter menu was constructed. In yet another treatment condition, participants were prompted to think about their own sustainable dietary goals, before being presented with the shorter menu.  In this last condition, when people were prompted to think about their own behaviour, the effectiveness of the green nudge increased by 30 percent.

These experimental findings are relevant because our diets contribute substantially to greenhouse gas emissions, globally as well as in the UK. The food delivery market is currently valued at more than 150 bn USD, after having expanded four to seven times during the pandemic, and it is expected to grow even more. Under these circumstances, food delivery companies can contribute to net–zero goals by introducing small design changes to their user–engagement platforms.

For example, the condition tried in the experiment, where thinking precedes nudging, can be easily implemented through push–in notifications that engage with citizens’ environmental preferences before they check out to place an order for their meal. The researchers believe that food delivery companies could also use long–term customer rewards to incentivise such in–app reflective behavioural interactions.

For comments or advice on how to use nudge+, please reach out to:

Sanchayan Banerjee; @SanchayanBanerj

Notes to Editors:

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