A Danish supermarket study used subtle yellow stickers to make healthy, sustainable food feel like a smart deal — no discounts needed.
What unsustainable behaviour needs to change:
It’s Friday afternoon. You’re tired after a long week, rushing through the supermarket on autopilot. You have good intentions — to eat healthier, shop more sustainably — but in the moment, those values are quickly overridden by fatigue, convenience, and price cues.
Sound familiar? This everyday scenario reveals why good intentions often fall short in the grocery store. Despite growing climate awareness, most of us still grab the convenient, familiar choices. The problem isn’t that we don’t care—it’s how our brains respond under pressure.
Here’s why:
Mental shortcuts under pressure (decision fatigue): When we’re tired and rushed, our brains default to familiar patterns
Too much information (cognitive overload): With thousands of products competing for your attention, we can’t process what’s truly sustainable
Bold price tags win (price salience bias): Eye-catching sale stickers trigger our deal-seeking instinct, regardless of actual value
Traditional campaigns often miss the mark on promoting more sustainable choices because they expect people to be deliberate. But most shopping is reactive– shaped by fast, unconscious judgments, not slow, rational decisions.
The Green Nudge:
In a study with a Danish supermarket, Krukow Behaviour Change tested a remarkably simple intervention:
Yellow dot stickers were added to healthy, everyday vegetables like cabbage, potatoes, and broccoli.
The dots mimicked „sale“ tags, using price cues to trigger the brain’s deal-seeking instinct — but without changing the price.
These items were placed in high-traffic areas, making them easy to grab without extra effort.
The results: Shoppers who encountered the yellow dots were 46% more likely to choose the healthier option.
No discounts. No education campaign. No added friction. Just a subtle visual cue that leveraged our brain’s automatic assumption that visually prominent items offer special value (price bargain heuristic).
The intervention cost virtually nothing to implement and required no staff training or system changes. This shows how design tweaks—not big budgets or awareness campaigns—can shift real-world behavior.
The Business Case: The yellow dot acts as an evolutionary nudge that drives purchase behaviour through instinctive attention cues — raising sales without eroding margins or requiring promotion spend.
What other clever in-store nudges have you spotted that actually work?
Feel free to get in touch: hello@green-nudges.com
From Sille Krukow, a global leader in Behaviour Design with over two decades of experience helping organizations like Procter & Gamble, Electrolux, and the European Commission turn behavioral insights into measurable sustainability outcomes. She’s a frequent keynote speaker and guest lecturer whose design based methodology shows how small environmental cues can drive big shifts in decision making.
