… are interventions, big or small, that aim to influence behaviour to make people act more sustainable.

The Green Nudges collection will be updated weekly (Tue 9am CET).

Social norms can increase towel reuse in the hospitality industry

Classic study from 2008 demonstrated that placing a card with social norms in the guest’s room triggers towel reuse

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How gamification is changing wasteful dishwashing habits

Reckitt Benckiser’s dishwasher tablet brand debunks pre-rinsing myths with the “Finish 24-Hour Challenge“

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Teaching recycling through gamification: The Waste Game

An interactive online tool designed to encourage waste prevention and recycling on Irish university campuses

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Roti reminder: When the food becomes the medium

Unilever’s Lifebuoy employed roti stamps to reinforce hand washing before eating meals in India

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“The Button Nudger” makes you push the right button

Pilot at Dutch University: nudge when flushing a dual-flush toilet to prevent excessive toilet water consumption

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The life extending fruit stickers that redefine freshness

Colombian changemakers predict a six-day extension in the life of fruits and vegetables through the implementation of stickers with serving meal suggestions

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“Recycle me!”: How anthropomorphism increases recycling responsibility

An US study that tested first-person communication on biscuit packaging demonstrated better recycling behaviour

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Empowering households: Energy displays provide control over energy bills

Energy displays for tenants act as constant reminders, offering immediate feedback and insight into their energy usage behaviour

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“Just-in-time” digital nudges at the point of food purchase

Dutch field experiment: Online supermarkets can deliver timely nudges that encourage people to make healthier and more sustainable food choices

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“Ballot Bins”: Vote with your cigarette butt and stop pollution

The quiz-like bins effectively engage people with buzzing questions, preventing cigarette butts from causing harm to wildlife and aquatic ecosystems

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Breaking the default: overcoming plastic cutlery habits

Using a simple prompt, a Beirut restaurant successfully reduced the use of plastic cutlery among customers placing food orders

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Reframing veggie dishes: The soy steak that became the summer plate

Making the vegetarian option more appealing to the mainstream by reframing it from a functional choice to an enjoyable one.

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The debunking sticker that shifts packaging choices

We have biassed perceptions of paper used in packaging. A “minimal packaging” sticker on a recyclable plastic-only option changes that.

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“Clear Bag Policy”: shifting waste management with social norms

The Canadian municipality implemented see-through bin bags which helped reduce the city’s overall solid waste as well as increase recycling rates.

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How smiley faces can improve energy efficiency

German „Deutsche See“ reduces fish refrigeration unit energy waste by 20% with smiley-face feedback system

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Breaking open defecation habits at Kumbh Mela festival

As part of the „Clean India Campaign,“ India is fighting the problem of open defecation. At the 2019 festival, they tackled this issue using behavioural nudges

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Fighting contamination: adding friction with shape-sorting bins

Singapore designer Tommy Cheong tackles recycling contamination by creating bins that activate your conscious “System 2”

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Relaxing Soundscapes in restaurants promote sustainable eating

New research highlights how sound can nudge us towards more sustainable food choices and promote planet-friendly eating habits

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Introducing Parkhuisje 3: A Green Nudge for Cleaner Parks

This Dutch reciprocity intervention offers a simple trade-off: easy meal ordering and delivery in exchange for a cleaner park.

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Small Plates, Big Impact: How Plate Size and Social Cues Affect Food Waste

An experiment at a hotel buffet showed that reducing plate size and providing social cues can reduce food waste by approximately 20%

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Heat-sensitive paint on radiators helps reduce energy waste

Danish approach: heat-sensitive paint on radiators signals when to turn off, potentially reducing heating consumption in public buildings

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A “climate receipt” making CO2 emissions transparent

Norwegian online supermarket, Oda, promotes sustainable shopping with a climate receipt displaying CO2 emissions alongside product prices.

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The sticker that nudges environmentally-friendly weed control

A Dutch study finds a sticker on a kettle is an effective nudge to promote the use of hot water instead of vinegar as a “green” herbicide.

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Visuals of untouched nature can reduce littering in communal spaces

An Austrian field experiment identified the most effective interventions to reduce littering in common waste disposal areas, testing four different methods.

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Bordeaux 2050: The wine from the future that tastes like Global Warming

An innovative campaign makes the future consequences of climate change tangible by showcasing its impact on one of France’s most famous cultural icons.

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Facial features in conservation campaigns can boost sustainable behaviours

Adding human-like features – such as eyes – in conservation campaigns can enhance intentional pro-environmental behaviours.

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Carbon labels on restaurant menus can impact food choices

Adding carbon labels next to food items on restaurant menus can decrease “high climate impact” meat orders.

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Gold star stickers on trash bins increase recycling rates

The City of Christchurch introduced a public reward and shaming scheme motivating citizens to better sort their garbage.

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Social imitation inlays in shopping trolleys to promote vegetable purchases

An experimental study in the Netherlands showed that social imitation inlays in shopping trolleys can promote vegetable purchases.

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Amphiro smart meter

Real-time feedback via Amphiro’s smart shower meter promotes energy conservation

Many people don’t actually know how much water and energy they use during their often daily shower. A field experiment in 6 Swiss hotels showed that smart shower meters with real-time feedback can reduce energy and water consumption.

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Making the CO2 footprint of food choices salient, makes people chose the better alternative

Customers at one of the largest cafeterias in Munich ordered food from a menu that gave them additional information on the sustainability of their choices. When faced with the negative cost, the individuals daily CO2 budget, and the amount of CO2 emission that each food option presented, buying behaviour changed. Customers bought less CO2 intensive choices, like less meat and fish, resulting in almost 10% less CO2 emission.

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Providing feedback with a smart packaging solution by Mimica

Every year we waste tons of food because the expiry date on the packaging says so. Mimica wants to change that with a temperature-sensitive, dynamic expiry label that provides accurate, real-time feedback of the product’s freshness.

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Social imitation

Opower’s neighbour comparisons. Saving energy by making sustainable peer action salient.

When our peers take actions to live more sustainable, we’re more likely to follow suit. Our social imitation was nudged by Utility companies by comparing our own energy consumption with that of our neighbours.

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Copenhagen’s elevated benches make future consequences tangible

Most often, people don’t care much about abstract, future consequences. To create awareness for what may come, some benches in Copenhagen have been elevated to match a realistic sea-level rise in the year 2100.

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A new default with Burger King’s “normal or with meat” campaign

Burger King makes the plant-based option the new normal. People who want the meat version deliberately have to opt-out. 

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Meet the team

Matthias Höppner


20 years ago, when Matthias first read Bill Buford’s book „Among the thugs“ – an impressive piece of social research about football hooligans and the power of the crowd – he was instantly hooked by the psychological phenomenons that make people tick. Ever since, he wanted to understand how people make decisions and what drives their behaviour. For many years, he tried to use this knowledge to influence purchase decisions, while working for many different companies as a marketing strategist. But increasingly, he’s interested in using that experience to influence people to make more sustainable choices.

Kassandra Huynh


Kassandra is a Creative Consultant, Biodesigner and Speculative Artist. With her expertise in nature-inspired social and sustainable design, she mentors start-ups and SMEs to transform their design products, services and systems. Not only does her guidance help companies generate circular designs, she also empowers them to push the boundaries of their storytelling resonance: encouraging interconnected and synergetic behaviors between people and their respective ecosystems. In her studio practice, she realizes playful and immersive experiences – ushering society towards proactive, inclusive and regenerative futures.

Johannes Fuchs


Johannes is a visual storyteller with work ranging from illustrations to design and art. His particular forté is in depicting visions of desirable futures and the roadmaps to how we could get there. As a communication designer, Johannes supports brands and stories on a mission to create a thriving planet. That’s why his core topics are sustainable and social impact, future design, and science communication. With his Green Nudges illustrations, Johannes skillfully disseminates the essence of often very theoretical behavioral insights; into accessible visual interpretations, approachable for a wide range of audiences.