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Contagious: Why Things Catch On

By: Jonah Berger 

Reviewed By: Ramona Sukhraj

As a marketer, you’re likely interested in what makes some ideas or products more popular than others; why they seem to be contagious like a case of chickenpox in a second-grade class.

Unfortunately, there is a certain degree of luck involved in virality, but there are also specific characteristics that are commonly found in all products and ideas that are contagious.

A number of people have tried to shed light on the subject including Nir Eyal and Chip and Dan Heath, but in this summary we'll give into Jonah Berger's Contagious: Why Things Catch On.

The Wharton marketing professor is highly regarded for his knowledge of what makes information go viral and in this book, he answers questions like:

  • What makes an idea, product, or brand popular?
  • Why do people talk about certain things more than others?
  • Why are some stories infectious while others are easily forgettable?
  • What makes online content go viral?

Plenty of marketers are quick to respond to those questions by saying advertising is what makes a product, idea, or brand contagious.

Berger, however, challenges that notion by showing that people don’t pay as much attention to advertisements as they do to what their peers say about something.

Word of Mouth is Contagious

“Contagious products and ideas are like forest fires. They can’t happen without hundreds, if not thousands, of regular Joes and Janes passing the product or message along.”

- Jonah Berger

Word of mouth marketing is more powerful than traditional advertising for two primary reasons:

  1. It’s more trustworthy
  2. It’s more targeted

Ads are not trustworthy.

We expect an ad to sell us on how great the product is, but out friends have got our back. They will tell us what they honestly think about a product as they have no ulterior motive.

Companies create traditional advertisements for a wide audience.

An ad on the evening news, for example, will be put in front of the millions watching (though only a portion of the viewers will actually see it.)

Word of mouth, on the other hand, is more targeted; being spread organically on a smaller scale, to people who are already interested.

The 6 Principles That Make Things Contagious

According to Berger, any product, idea, or behavior can be contagious – as long as you build in the following principles.

#1 Social Currency

There are three ways to leverage social currency:

  1. Find inner remarkability. Share entertaining, innovative, or gripping stories that make your product, service, or information more interesting for people to talk about.
  2. Leverage game mechanics. People enjoy competition and they especially enjoy sharing status symbols like awards and prizes. Adding the element of "gamification" or something similar gives people an incentive to show off your product to others.
  3. Make people feel like insiders. The more exclusive something appears to be, the more people want it. Using a high price or scarcity tactics make your thing harder to obtain, which raises its social value.

#2 Triggers

What triggers people to think about your product or idea; to use your service? How can you connect it with something that makes it come to mind more often?

For example, the candy company Mars noticed an unexpected increase in sales of its Mars bar in 1997 when NASA had a well-publicized mission to Mars.

What similar news events can you align your brand with? This is the idea behind newsjacking

#3 Emotion

Focus on feelings. What emotions result from your brand or idea? What emotions will resonate with your audience and prompt action?

#4 Public

Can people see when others are using your product? How can you leverage social media to make it more public? Find a way to promote social sharing. 

#5 Practical Value

Does spreading the word about your product or idea help others?

Position your product or service in a way that highlights value or provides knowledge that people feel obliged to share with others. 

Your content needs to educate, entertain, inform, or offer financial value that makes people feel inclined to pass it on to another.

#6 Stories

Is your product or idea embedded in a narrative that people care about and can easily understand? By wrapping your message in a memorable brand story, you make it more "shareable."

A good brand story incorporates all of the five elements above and creates a package that people want to spread. 

Conclusion: Create Top-Of-Mind Awareness

Berger conducted a study where his goal was to encourage students on campus to eat more fruits and vegetables.

The premise was that students already know they should eat more fruits and vegetables (and many would actually do so if they were reminded), but in most cases they chose to eat a burger and fries instead.

After measuring the actual consumption of fruits and vegetables, Berger exposed two groups to different marketing messages.

The first group saw “Live the healthy way, eat five fruits and vegetables a day;" the second, “Each and every dining hall tray needs five fruits and vegetables a day.”

The two messages were similar, but the second referred to the dining hall tray. Oddly enough, the students rated that message as “corny” and when asked if they thought the slogans would impact their behavior the majority said “no.”

As I’m sure you can guess, despite the feedback, the second message that included the reference to the food tray actually changed the students’ behavior, while the other one didn’t.

The reason is simple – the trays triggered them to remember the message.

Do you remember Rebecca Black’s song “Friday?”

When you look at the search history for “Rebecca Black” on YouTube, you will notice that searches peaked every Friday for months after the song was released because the day triggered a reminder for people. If a trigger can make that song successful, what can it do for your product or idea?

You have to figure out which triggers you can associate with the behavior you are trying to influence.