Contagious – Why Things Catch On by Jonah Berger (Professor of Marketing at The Wharton School of Business, University of Pennsylvania) distills years of research into understanding why certain ads, products, YouTube videos, political movements, songs, and/or restaurants catch on, while others are ignored. The premise was simple. Whether you are in marketing, politics, engineering or public health, you need to understand how to make your ideas and products catch on. The book explains what makes content contagious. Content- Stories, news, information and ideas

Why some ideas and products become popular is that they are just plain better faster and cheaper. So when something comes along that offers better functionality or does a better job, people tend to switch to it. For instance, bulky and heavy televisions and monitors were the vogue in the past but with the introduction of flat screen things were better.

Another reason products catch on is attractive pricing- It is a know thing that people prefer paying less rather than more. Advertising equally plays a key role in the sense that a consumer need to know about something before they can buy it.

In a more clearer terms, quality, pricing and advertising are major pushers of ideas, products to the consumer.

No doubt, this three attributes contributes to how a product and idea flies but that is not the whole story. If quality, pricing and advertising does not explain why one firts name is more important than the other.


Social influence and word of mouth. People love to share stories, news and information with those around them. We tell friends about great vacation destination, chat with our neighbors. We try websites our neighbors recommend, read books our relatives, praise and vote for candidates our friends endorse.

Word of mouth is the primary factor behind 20% – 50% of all purchasing decisions. For example, a word of mouth by a new customer leads to an almost $200 increase in restaurant sales.

While traditional advertising is still useful, word of mouth from everyday Jones and Janes is at least ten times more effective. This is because ads will always argue that their products are the best, they are not really credible. Our friends however tell it straight to us. If Tecno did a good product, they would say it. They will also tell us a Tecno product works badly or failed to meet their expectation.

Their objectivity makes us more likely to trust, listen to and believe our friends.

> Word of mouth is more targeted (for example, A company that sells skis television ads during the nightly news because probably would not be very efficient because many of the viewers don’t ski. So the company might advertise in a ski magazine) unlike paid adverts.

> Word of mouth is directed at interested audience. We don’t share a new story or recommendation with everyone we know. Rather, we tend to select particular people who we think would find that given piece of information most relevant. We are not going to tell a friend about a new pair of skis if we know the friend hates skiing. We are also not going to tell a friend who doesn’t have kids about the best way to change a diaper.

Ingredients Of Contagious Messages/ Ideas/Product

These ingredients can also be called STEPPS

Social currency

How does it make people look to talk about a product or idea? Most people would rather look smart than dumb, rich than poor, and cool than geeky. Just like the clothes we wear and the cars we drive, what we talk about influences how others see us. It’s social currency. Knowing about cool things—like a blender that can tear through an iPhone—makes people seem sharp and in the know. So to get people talking we need to craft messages that help them achieve these desired impressions. We need to find our inner remarkability and make people feel like insiders. We need to leverage game mechanics to give people ways to achieve and provide visible symbols of status that they can show to others.


How do we remind people to talk about our products and ideas? Triggers are stimuli that prompt people to think about related things. Peanut butter reminds us of jelly and the word “dog” reminds us of the word “cat.” If you live in Philadelphia, seeing a cheese steak might remind you of the hundred-dollar one at Barclay Prime. People often talk about whatever comes to mind, so the more often people think about a product or idea, the more it will be talked about. We need to design products and ideas that are frequently triggered by the environment and create new triggers by linking our products and ideas to prevalent cues in that environment. Top of mind leads to tip of tongue.


When we care, we share. So how can we craft messages and ideas that make people feel something? Naturally contagious content usually evokes some sort of emotion. Blending an iPhone is surprising. A potential tax hike is infuriating. Emotional things often get shared. So rather than harping on function, we need to focus on feelings. But as we’ll discuss, some emotions increase sharing, while others actually decrease it. So we need to pick the right emotions to evoke. We need to kindle the fire. Sometimes even negative emotions may be useful.


Can people see when others are using our product or engaging in our desired behavior? The famous phrase “Monkey see, monkey do” captures more than just the human tendency to imitate. It also tells us that it’s hard to copy something you can’t see. Making things more observable makes them easier to imitate, which makes them more likely to become popular. So we need to make our products and ideas more public. We need to design products and initiatives that advertise themselves and create behavioral residue that sticks around even after people have bought the product or espoused the idea.

Practical value

How can we craft content that seems useful? People like to help others, so if we can show them how our products or ideas will save time, improve health, or save money, they’ll spread the word. But given how inundated people are with information, we need to make our message stand out. We need to understand what makes something seem like a particularly good deal. We need to highlight the incredible value of what we offer—monetarily and otherwise. And we need to package our knowledge and expertise so that people can easily pass it on.


What broader narrative can we wrap our idea in? People don’t just share information, they tell stories. But just like the epic tale of the Trojan Horse, stories are vessels that carry things such as morals and lessons. Information travels under the guise of what seems like idle chatter. So we need to build our own Trojan horses, embedding our products and ideas in stories that people want to tell. But we need to do more than just tell a great story. We need to make virality valuable. We need to make our message so integral to the narrative that people can’t tell the story without it.

The one thing that I kept thinking as I read this book is that people need to start creating advertisements to affect their own behavior.

What I mean by that is that we can implement some of these principles to affect our own habits, thoughts, and actions in our life, as well as influencing others. The other major thing that I took away is that everything is about focusing on feelings. I’m very logic-driven, so that has always been foreign to me, but it’s 100% true.

Finally, the last thing I took away is that feelings drive action, not thoughts. Thoughts might drive feelings which drive action, but ultimately it’s the underlying feelings that cause action.