Walk down a suburban street, and you might stumble across a following sign. It’s probably messy with poor formatting and inconsistent font size. Here’s one that I saw in Houston.
One line stuck out to me. It reads, “Window cleaning in progress.” I love this board because it showcases something that most marketers forget. K&C Window Cleaning doesn’t try to persuade you with flashing slogans or in-your-face claims. They’re far more subtle, and that subtly makes them more effective.
While ads are about influence, no one wants to be sold to. Instead, this sign uses psychology to get people thinking, “Other people are using the service, so maybe it’s time to clean my windows.” The idea feels organic and nothing feels forced.
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We follow the actions of others
Back in 2008, the legendary researcher Robert Cialdini ran a notorious study. Set up over 80 days in a mid-priced hotel in the American Southwest, the three researchers ran tests in 190 rooms. Their goal was to encourage visitors to reuse their towels. Inside the room, they tested different signs with over 1,058 guests.
First, they tested a standard environmental message saying, “Help save the environment.” Guests said this message would be most likely to persuade them. But the researchers also tested a message that read “most guests reuse their towels.” The results were surprising. 
The environmental plea encouraged 35% reuse, but the suggestion that the majority of guests reused their towels boosted reuse to 44%. But, then they added a third message: “Most guests in this room reuse their towels.”
This had an even greater impact. Now, almost 50% of guests reused old towels, up from 35% in the control. The takeaway is simple: we follow the actions of others.
So, if a neighbor pays for window cleaning, we’ll consider doing the same. But marketers forget one important element: Consumers don’t like to feel forced.
We don’t like to feel forced
Messages like “we’re the most popular” and “we’re number one” work, but they’re not perfect. Nicolas Guéguen in 2000 showed that people are more likely to act if they feel autonomous, not forced.
The study attempted to persuade French commuters to spare some coins for a bus ticket. The researchers tried two messages, which yielded surprisingly different results:
- “Sorry, would you have some coins for me to take the bus, please?“ 10% agree
- “Sorry, would you have some coins for me to take the bus please? But, you are free to accept or refuse.” 47.5% agree
This method, coined the “but you are free to refuse” technique, has been proven in multiple different domains, both online and offline. A 2013 meta-analysis found that the effect worked across 42 different domains.
That brings us back to K&C Window Cleaning’s sign. It takes all this advice to heart. It showcases the actions others take, but doesn’t force the reader into a corner.
- It doesn’t say, “We’re the most popular window cleaners in Houston.”
- It says, “Window cleaning in progress.”
And plenty of other companies do the same. They don’t say they’re popular; they prove it.
My favorite example comes from Sam Tatam’s wonderful book, Evolutionary Ideas. At his favorite cafe in Sydney, Australia, the owners don’t say, “We’re popular.” Instead, they show it by sticking the loyalty cards of their customers on the wall.
Don’t say it. Show it. It’ll make your message far more effective.
Make decisions feel natural
If you believe in your offering, you’ll want to brand it as the best, brightest, and most popular. Resist the urge. The best marketers let customers make their own decisions by showing value. The most persuasive thing you can do is make your customer feel like the idea was theirs all along, backed by peers who have also reaped benefits.