The key ideas

Contagious: Why Things Catch On

Jonah Berger, 2013

Why do people talk about a restaurant because of one sandwich, and why have hundreds of millions of people watched videos about a blender? Wharton professor Jonah Berger spent more than ten years studying what makes people pass ideas on and recommend things to each other. He found six reasons, and you can use every one of them without a big advertising budget.

Who it is for

For anyone launching a product, a business or a project who wants people to talk about it. And for anyone curious why some stories get retold by everyone, while others are forgotten the next day.

Just like the clothes we wear and the car we drive, what we talk about affects how others see us.

The hundred-dollar cheesesteak

In 2004 Howard Wein was helping to open Barclay Prime, an upscale steakhouse in Philadelphia. The city already had plenty of good restaurants, and there was no money for a big advertising campaign. The guests themselves had to start talking about the new place. So Wein came up with a hundred-dollar cheesesteak.

An ordinary Philly cheesesteak, a roll with fried beef and cheese, costs a few dollars at any snack bar. Wein filled his with marbled beef, truffles and lobster tail, and served it with a small bottle of champagne. Major newspapers wrote about the sandwich, and David Beckham ordered one. Even people who had never set foot in the restaurant talked about it.

Jonah Berger teaches marketing at Wharton, the business school of the University of Pennsylvania. For more than ten years he studied why some things get passed on by word of mouth while others are forgotten. According to the data he cites, personal recommendations drive 20 to 50 percent of buying decisions. The book's main finding: it is less about special people with huge circles of friends and more about the message itself. Some stories get retold no matter who starts telling them.

Berger found six reasons people start talking about something, and put their first letters together into one word: STEPPS. Ahead are a secret bar behind a phone booth, a chocolate bar that sold better thanks to a mission to Mars, and an ad campaign that achieved the opposite of its goal. And by the end you will see how to get people talking about your idea even when you are not in the room.

The blender that blended an iPhone

Engineer Tom Dickson made excellent blenders, but hardly anyone had heard of his brand, Blendtec. One day the new marketing director, George Wright, noticed a pile of sawdust on the factory floor. It turned out Dickson tested the blenders every day by grinding wooden boards in them.

Wright spent about five hundred dollars on marbles, golf balls and a white lab coat. Dickson dropped fifty marbles into the blender, and fifteen seconds later they were dust. The video got six million views in its first week. Then lighters, CDs and even an iPhone went into the blender.

Berger calls this finding the inner remarkability of a product: even an ordinary thing has something about it that can surprise. And people enjoy telling others about surprising things, because it makes the teller look like someone in the know. The author gathers everything that helps a person look good in the eyes of others under one name: social currency.

A blender is hardly a thrilling product, yet the videos about it have been watched hundreds of millions of times. Hence Berger's key point: virality can be created, not just waited for.

Read in Livria

About the author

Jonah Berger is a professor of marketing at the Wharton School of the University of Pennsylvania. He studies why products and ideas catch on and what people talk about with each other.

All books by this author: Jonah Berger

Terms from the book

  • Jobs
  • Mitchell
  • Virality
  • Wright
  • Awe
  • Wharton
  • Carroll
  • Black
  • Trigger
  • Barclay Prime: An upscale steakhouse in Philadelphia that opened in 2004. It became famous for a hundred-dollar cheesesteak.
  • Wein: Howard Wein, an American restaurateur who worked for the Starwood hotel group. He came up with the hundred-dollar cheesesteak for Barclay Prime.
  • Cheesesteak: The Philadelphia sandwich: a long roll filled with thinly sliced fried beef and melted cheese.
  • Beckham: David Beckham, the English footballer, one of the best-known stars in world sport.
  • Word of mouth: News, opinions and recommendations passed from person to person, by talking, with no advertising involved.
  • STEPPS: The author's acronym, made of the first letters of his six principles: Social currency, Triggers, Emotion, Public, Practical value, Stories. It is the author's framework, not a scientific term.
  • Dickson: Tom Dickson, an American engineer and the founder of Blendtec. He starred in the videos himself, blending unusual things.
  • Blendtec: An American company from Utah that makes powerful blenders. It became famous for its video series "Will It Blend?".
  • Social currency: The author's term for anything that makes a person look better in the eyes of others when they talk about it. The first of the book's six principles.
  • Crif Dogs: A hot dog joint in New York. A phone booth inside it leads into the bar Please Don't Tell.
  • Please Don't Tell: A small bar in New York whose entrance is hidden in a phone booth inside the Crif Dogs hot dog joint.
  • Tamir: Diana Tamir, a Harvard researcher, co-author of the study showing that talking about yourself activates the brain's reward system.
  • Game mechanics: Techniques borrowed from games and used outside them: levels, points, status. In the book they are one way to give people social currency.
  • Mars: The American confectionery company that makes the Mars bar. The bar is named after the company's founder, Franklin Mars.
  • Pathfinder: The NASA mission that landed a probe carrying a small rover on Mars in 1997.
  • Cheerios: A popular American breakfast cereal: little rings of oat.
  • Kit Kat: A chocolate bar made of wafer fingers covered in chocolate.
  • Milkman: Katherine Milkman, a Wharton professor and Berger's co-author on the study of which articles people share most.
  • Boyle: Susan Boyle, a Scottish singer. She became famous in 2009 when, completely unknown, she sang on a British TV talent show.
  • United: United Airlines, one of the largest airlines in the United States.
  • Movember: A yearly campaign and charity: in November men grow moustaches to draw attention and money to men's health. The name blends "moustache" and "November".
  • Livestrong: A foundation that supports people living with cancer. Its yellow silicone wristbands became a widespread sign of support.
  • Behavioral residue: A term from the book: the trace an action leaves behind that other people can see, such as a wristband or a sticker.
  • Hotmail: One of the first free email services, launched in 1996.
  • Craig: Ken Craig, an 86-year-old American whose video on how to shuck corn quickly spread across the internet.
  • Rule of 100: The author's advice: for a product under a hundred dollars, state the discount as a percentage; for one above, state it in dollars. That way it seems bigger.
  • Evian: A French brand of mineral water.
  • Valuable virality: The author's term for a story that spreads and helps the product at the same time, because you cannot retell it without the product.
  • Panda: A cheese brand known for a series of ads in which a panda wrecks everything around people who turn down the cheese.

All terms

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