Contagious: Why Things Catch On

by Jonah Berger

So using the word “sale” beside a price increased sales even though the price itself stayed the same.

Diminishing sensitivity reflects the idea that the same change has

a smaller impact the farther it is from the reference point.

The same change—gaining ten more dollars—has a smaller and smaller impact the farther you move from your reference point of zero dollars or not winning anything.

Diminishing sensitivity helps explain why people are more willing to drive to save the money on the clock radio. The clock radio was much cheaper, so a discount from $35 to $25 seems like a pretty good deal. But even though the television is also $10 off, it doesn’t seem like a bargain given how much more expensive the television was in the first place.

Deals seem more appealing when they highlight incredible value.

As prospect theory illustrates, one key factor in highlighting incredible value is what people expect.

The same is true even with the word “sale.” While noting something is on sale can increase demand, if too many items in a store are listed as being on sale, it can actually reduce purchase.

But offers that are available for only a limited time seem more appealing because of the restriction. Just like making a product scarce, the fact that a deal won’t be around forever makes people feel that it must be a really good one.

Indeed, research finds that quantity purchase limits increase sales by more than 50 percent.

Researchers find that whether a discount seems larger as money or percentage off depends on the original price. For low-priced products, like books or groceries, price reductions seem more significant when they are framed in percentage terms. Twenty percent off that $25 shirt seems like a better deal than $5 off. For high-priced products, however, the opposite is true.

If the product’s price is less than $100, the Rule of 100 says that percentage discounts will seem larger. For a $30 T-shirt or a $15 entrée, even a $3 discount is still a relatively small number. But percentagewise (10 percent or 20 percent), that same discount looks much bigger.

The problem with this assumption, though, is that just because people can share with more people doesn’t mean they will. In fact, narrower content may actually be more likely to be shared because it reminds people of a specific friend or family member and makes them feel compelled to pass it along.

So while broadly relevant content could be shared more, content that is obviously relevant to a narrow audience may actually be more viral.

Our desire to share helpful things is so powerful that it can make even false ideas succeed. Sometimes the drive to help takes a wrong turn.

So the next time someone tells you about a miracle cure, or warns about the health risks of a particular food or behavior, try to verify that information independently before you pass it on. False information can spread just as quickly as the truth.

Practical value is about helping. This chapter discussed the mechanics of value and the psychology of deals, but it’s important to remember why people share that type of information in the first place. People like to help one another.

Of the six principles of contagiousness that we discuss in the book, Practical Value may be the easiest to apply.

Some products and ideas already have lots of Social Currency, but to build it into a video for a blender takes some energy and creativity. Figuring out how to create Triggers also requires some effort, as does evoking emotion. But finding Practical Value isn’t hard. Almost every product or idea imaginable has something useful about it.

The city was able to stand a decade of battle, but it could not withstand an attack from within. Once inside, the Greeks destroyed the town, decisively ending the Trojan War.

But the story of the Trojan Horse also carries an underlying message: “Beware of Greeks bearing gifts.” A more general interpretation would be “never trust your enemies, even when they seem friendly.” In fact it is exactly when they are making such overtures that you should be especially suspicious.

By encasing the lesson in a story, these early writers ensured that it would be passed along—and perhaps even be believed more wholeheartedly than if the lesson’s words were spoken simply and plainly. That’s because people don’t think in terms of information. They think in terms of narratives. But while people focus on the story itself, information comes along for the ride.

Narratives are inherently more engrossing than basic facts.

Today there are thousands of entertainment options, but our tendency to tell stories remains.

People tell stories for the same reasons they share word of mouth. Some narratives are about Social Currency. People tell the story of going through the phone booth to get into Please Don’t Tell because it makes them look cool and in the know. Other stories are driven by (high arousal) Emotion. People tell the story of Will It Blend? because they are amazed that a blender could shred marbles or an iPhone. Practical Value also plays a role. People share the story of how their neighbor’s dogs got sick after eating a certain type of chew toy because they want your dog to avoid the same fate.

We’re so used to telling stories that we do it even when a simple rating or opinion would have sufficed.

Stories carry things. A lesson or moral. Information or a take-home message.

The third pig, however, is more disciplined. He takes the time and effort to carefully build his house out of bricks, even while his brothers have fun around him.

And that’s the moral of the story. Effort pays off. Take the time to do something right. You might not have as much fun right away, but you’ll find that it’s worth it in the end.

Stories, then, can act as vessels, carriers that help transmit information to others.

You can think of stories as providing proof by analogy.

People are also less likely to argue against stories than against advertising claims.

Second, we’re so caught up in the drama of what happened to so-and-so that we don’t have the cognitive resources to disagree. We’re so engaged in following the narrative that we don’t have the energy to question what is being said. So in the end, we’re much more likely to be persuaded.

The story gets shared for many of the reasons we talked about in prior chapters. It’s remarkable (Social Currency), evokes surprise and amazement (Emotion), and provides useful information about healthy fast food (Practical Value).

And that is the magic of stories. Information travels under the guise of what seems like idle chatter.

So how can we use stories to get people talking? We need to build our own Trojan Horse—a carrier narrative that people will share, while talking about our product or idea along the way.

Piper made the film in coordination with Dove, maker of health and beauty products, as part of its “Campaign for Real Beauty.”

“Evolution” was widely shared because Dove latched onto something people already wanted to talk about: unrealistic beauty norms.

There’s a big difference between people talking about content and people talking about the company, organization, or person that created that content.

The key, then, is to not only make something viral, but also make it valuable to the sponsoring company or organization. Not just virality but valuable virality.

Virality is most valuable when the brand or product benefit is integral to the story. When it’s woven so deeply into the narrative that people can’t tell the story without mentioning it.

But note that what makes these videos so great is not just that

they’re funny.

They’re successful—and great examples of valuable virality—because the brand is an integral part of the stories.

But which details people remember and retell? It isn’t random. Critical details stick around, while irrelevant ones drop out.

Around 70 percent of the story details were lost in the first five to six transmissions.

But the stories didn’t just become shorter: they were also

sharpened around the main point or...

If you want to craft contagious content, try to build your own Trojan Horse. But make sure you think about valuable virality. Make sure the information you want people to remember and transmit is critical to the narrative.

So build a Social Currency–laden, Triggered, Emotional, Public, Practically Valuable Trojan Horse, but don’t forget to hide your message inside. Make sure your desired information is so embedded into the plot that people can’t tell the story without it.