What is the Supermarket Nudging Method?
Nudging experiments are a technique drawn from behavioural science and public policy that seek to influence decisions subtly, without restricting the options available. A nudge works by changing how choices are presented, often at low cost. For example, a glass of water can be both half empty and half full. Both represent the same outcome but half full is merely perceived as something positive, whereas half empty can be linked to negative emotions. Nudging can be used to encourage pro-environmental or pro-social behaviour. With regards to biodiversity, nudges can be used to draw attention to ecological or social issues, make biodiversity positive options easier to notice and adapt to, or point towards social norms that support care for the environment.
In PLANET4B, nudging experiments were used to explore how social prompts and emotional cues could foster greater attention to biodiversity in everyday decision-making in the context of food purchasing. Short texts and images were developed to present information about biodiversity loss, evoking empathy, humour to motivate action. These nudges were tested in a field experiment (i.e. observing people’s natural behaviour in everyday settings without influencing their actions) in supermarkets. The aim was to understand which types of nudges were most effective in encouraging biodiversity-friendly choices during daily shopping.
In this module, Ilkhom Soliev outlines how the nudging method was developed and applied in PLANET4B. He introduces the PLANET4B case study in the video below:
In this video Ilkhom Soliev introduced the Supermarket Nudging method:
Key Features:
Partners and Participants
- To support implementation, nudging experiments often require partners. Private sector or civil society organisations may be needed to host or facilitate the experiment, while policy actors can play a role in scaling out successful approaches
- In nudging experiments, participants are the people who directly engage with the nudge – in the PLANET4B project, this meant supermarket shoppers.
- People who interact with the nudge provide a pool for data collection. Following up on an intervention with a survey (or, alternatively, a participant interview or debriefing meeting) offers a chance to better understand if, and how, the intervention influences behaviour
Timeframe - The timeframe depends on the scale of the method; however, you will want to account for:
- Researching, involving planning, developing a research question, and identifying both the target group and the most appropriate nudge to apply
- Building connections and securing permissions, for example with a willing supermarket partner
- Planning the logistics of the experiment, including scheduling, determining the sample size, selecting a control group, and designing a post-nudge survey
- Obtaining ethical approval since human subjects are involved
- Piloting the method, where possible, to ensure it runs smoothly
- Carrying out the method, including setting up the nudge and engaging participants
- Data analysis, drawing out patterns and insights from the responses - this might take significant time, especially with regards to in-depth data analysis
- Planning, for how findings will be shared, scaled, or applied in practice
Materials and Budget - Nudging can be a low-cost method, but budgets need to cover the following:
- Design of materials (e.g. signs, posters, information packs)
- Staff costs for designing and delivering the nudge may include time for researching suitable interventions and supporting implementation, such as staffing to distribute surveys and assist during the activity
- Field logistics involving transport and any subsistence costs of those carrying out the method
- Field experiments may also require resources for collaboration with retailers or other partners
- Depending on your project, you may wish to budget for small participant incentives, such as a random prize draw for survey respondents or a simple token of appreciation, for example offering participants a fairtrade chocolate bar completing the post-intervention survey
Skills – Nudging experiments require a combination of skills; it is therefore recommended that they are conducted by a team with combined areas of expertise including:
- Knowledge of relevant biodiversity challenges, and an understanding of the behaviours and changes that could have a positive impact upon biodiversity-related choices
- Research skills, including experimental design and the ability to write clear and compelling nudging prompts
- Skills in survey development, statistical analysis, and ethical research practice
- Facilitation and negotiation skills, particularly when working with private sector partners such as supermarkets
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Why Use Nudging Methods
Nudging methods influence everyday decisions in subtle ways without restricting choice. They are most effective when people face complexity, act out of routine, or have limited knowledge about an issue, as these contexts encourage automatic decision-making. Making the environmental option easy to select is therefore vital, since reducing complexity and effort increases the likelihood of pro-environmental choices. By presenting information differently, highlighting social norms, or evoking emotional responses, nudges can raise awareness of biodiversity and make sustainable behaviour more appealing and accessible.
In PLANET4B, nudging experiments tested whether short texts and images could activate social norms or emotions, such as empathy or humour, to encourage biodiversity-friendly shopping choices. The approach is valuable because it can be applied at scale, requires relatively few resources, and can support businesses, policymakers, and communities in shifting norms and habits in ways that contribute to biodiversity goals.
In this video, Ilkhom Soliev discusses some of the benefits of using the nudging methods:
For more information on the benefits of nudging and to see how they have been carried out in different contexts visit:
The Little Book of Green Nudges – a concise and accessible guide aimed at universities and student communities, offering evidence-based ideas to reduce environmental impacts through behavioural change. It summarises what types of nudges (choice architecture, defaults, social influence, salience) tend to work best and gives practical tips on how to design, implement and evaluate them.
Nudging for Pro Environmental Behaviour - reviews empirical cases across four main categories of nudges: providing information, altering the physical environment, changing default options, and leveraging social norms with feedback. It focuses on applications in energy use, waste management, and resource efficiency. The findings suggest that while information nudges are most common, substantial gains often come from social norms and default options, and that changes to the physical environment such as repositioning bins or reducing plate size, can be particularly effective in waste and recycling contexts.
Informational Nudges to Encourage Pro-environmental Behavior: Examining Differences in Message Framing and Human Interaction - tests how framing messages (positive vs negative) and interpersonal communication affect behaviour using natural field experiments (e.g. reducing plastic bag use, preventing reef damage).
Nudging Toward Sustainable Food Consumption at University Canteens: A Systematic Review and Meta-Analysis - synthesises many interventions related to food choices, highlighting which kinds of nudges (labelling, defaults, contextual cues) tend to produce measurable change, and where evidence remains sparse.
The Ethics of Nudging: An Overview - offers a clear framework for thinking about moral questions around nudging: consent, transparency, fairness, unintended consequences. It is useful when designing nudges in sensitive or contested domains like environmental behaviour.
Nudging: Progress to Date and Future Directions - this article offers a comprehensive review of nudging to date, mapping what has been achieved and identifying where more work is needed. It discusses how nudges differ in design, effectiveness, context sensitivity and ethical concerns, useful for understanding both the promise and the limits of behavioural interventions in environmental or social settings.
In this video, Ilkhom Soliev explains how the nudging intervention in PLANET4B was designed and implemented to support biodiversity:
