Flush, honk, flirt: behaviour change through humour
Humour isn’t just a punchline—it’s a potent tool for behaviour change, especially when tackling serious issues like sustainability, health, or social justice. In Australia, brands like Who Gives A Crap have mastered the art of using humour to drive meaningful action.
Let’s delve into how they do it and what we can learn!
Who Gives A Crap: Toilet humour that builds toilets
Australian social enterprise Who Gives A Crap has raised millions for global sanitation, not through guilt-tripping consumers — but by cracking them up. Their packaging is bright, cheeky, and full of puns (“Good for your bum. Great for the world.”). Even the product descriptions are laced with irreverence, transforming the often-taboo topic of defacation into something customers are proud to talk about.
Their limited-time “Flush Your Ex” campaign for Valentine’s Day a few years ago went viral: for a small donation, people could symbolically “flush” their ex’s name — with all proceeds going to toilet-building projects. It was funny, it was cathartic, and it nudged thousands to engage in a cause they might otherwise overlook.
https://flushyourex.whogivesacrap.org/
Mumbai’s “Punishing Signal”: Out-honking the honkers
Mumbai, one of the world’s noisiest cities, trialled a campaign where the more people honked at a red light, the longer the red light lasted. A digital sign counted the decibels — and when it exceeded 85dB, the timer reset. The message: “Honk More, Wait More.”
What made it work? It was unexpected, playful, and turned the tables on a behaviour most drivers didn’t even think twice about. By using humour and surprise rather than scolding, it created an “aha” moment for many — and a measurable drop in noise pollution.
This is a great example of using the nudge category of ‘aversion’ to change behaviour - disincentivising the behaviour you don’t want.
Video of this intervention in action here.
The Ministry of Silly Bins
In Sweden, the city of Stockholm installed talking rubbish bins that moaned, cheered, or delivered saucy messages every time someone threw something away. Instead of signs pleading “Keep your city clean,” these bins flirted, joked, and praised your recycling prowess.
The result? A 50% increase in bin usage during the trial. It turns out, we’re more likely to engage when the reward is an unexpected giggle — not just a clean conscience.
More info here.
Dutch urinals and the fly
One of the earliest and most elegant humorous nudges came from Amsterdam’s Schiphol Airport. Tired of cleaning up after poor aim in men’s toilets, designers etched the image of a black fly into the urinal — right near the drain. Why? Because men, it turns out, like to aim.
The results were startling: spillage reduced by 80%. No signs. No instructions. Just a bit of playful design that appealed to instinct. It’s behavioural economics with a wink.
So why does humour work?
Under the hood, humour isn’t fluff. It’s a fast-track to behaviour change, thanks to a few key psychological levers:
1. Positive affect boosts receptivity
When we’re laughing, we’re more open. Positive emotions expand cognitive processing, increase creative thinking, and lower defensiveness — what psychologists call the broaden-and-build theory (Fredrickson, 2001). This makes us more likely to take in new information and try something different.
2. Disarming complexity and taboo
Humour helps us engage with otherwise uncomfortable or complex topics — whether it’s climate change, hygiene, or heartache. It reframes the message, reducing psychological friction. This is especially powerful when trying to address cultural taboos or fatigue-inducing subjects.
3. Social proof and shareability
Humour increases recall. Studies show that messages paired with humour are remembered better over time than those that aren’t. It also creates intrinsic motivation: we want to return to the experience that made us laugh.
5. Incongruity grabs attention
Salience matters. Humour often works through incongruity resolution — something unexpected that gets resolved in a surprising way. That cognitive “ping” is what gets attention in a noisy world.
What this means for designers
If you’re designing a behaviour change intervention — whether in public policy, workplace culture, or customer engagement — consider humour another tool in your behaviour change belt. It’s not just about getting a chuckle, but rather about creating a positive emotional frame around your message.
Questions to ask yourself:
Can I make this message lighter without diluting the goal?
What would this look like if it was funny on purpose?
How can humour be used to invite, not mock?
Humour doesn’t trivialise behaviour change. It humanises it.