Start with behaviour, not the message

1. Why informing alone isn’t enough

Every day, powerful sustainability campaigns grab people’s attention, and then nothing happens. People nod, they like the message, they might even feel inspired for a moment… and then carry on with their habits. Awareness alone doesn’t create change.

Real impact happens when communication turns intention into action. And to do that, you need more than a message. You need behavioural design: a way to understand what drives or blocks action and build your strategy around it.

2. Start with the behaviour, not the message

Behavioural design is not about finding the right slogan. It’s about starting with a simple but powerful question:

 “What behaviour do we actually want to see?”

Once that’s clear, the next step is to map:

• What triggers this behaviour: the moments, emotions, contexts or incentives that make it easier to act.
• What blocks this behaviour: the frictions, doubts, social norms or practical obstacles that stop people.
• What drivers can be leveraged: values, habits, social proof, ease of use.

Only then do you design your communication and activation strategy around these insights. This means your campaign isn’t built on assumptions, it’s built on real human behaviour.

3. Case: BoekenBalie: breaking habits

A perfect example of this approach is our work with BoekenBalie, an online platform for buying and selling second-hand books.

In the Netherlands, 66% of people say they believe it’s a waste to buy new books when second-hand options are available. And yet, most still reach for new. Why? Because buying new is a deeply ingrained habit. It feels easier, more familiar, more reliable. So instead of starting with what BoekenBalie wanted to say, we started with the behaviour we wanted to change: making second-hand books the first choice.

We mapped the landscape:

• Triggers: price advantages, environmental benefits, the joy of finding a unique book.
• Barriers: perceived hassle, doubts about quality, fear of missing out on new releases.
• Drivers: love for books, sustainable values, and the cultural shift toward conscious consumption.

With these insights, we developed a new brand positioning, a rebranding and a creative campaign concept all built around shifting behaviour, not just telling a story.

Instead of presenting second-hand as the “alternative,” we framed it as the default, smarter choice.The communication focused on ease, relevance, and pride in making sustainable choices. The brand narrative didn’t just talk about impact, it gave people a reason and a way to act on their own beliefs.

4. Embedding behavioural design in your communication

You don’t need to rebuild your entire strategy overnight. Start with small shifts:

1. Design for action, not awareness. Every message should lead to a clear, simple next step.
2. Make it human. Use real stories, real voices, and relatable language.
3. Build collective momentum. Activate communities, not just audiences.
4. Measure behaviour, not just reach. Success is in what people do, not just what they see.

Communication alone can spark a thought.
Behavioural design turns it into a movement.