Key Insights: Contagious: Why Things Catch On
Author: Jonah Berger • Category: Business & Leadership
Berger's claim is that word of mouth is not luck and not a function of advertising budget. Six drivers decide whether a product, idea, or video gets talked about, grouped under the acronym STEPPS: Social Currency, Triggers, Emotion, Public, Practical Value, Stories. Each is a mechanism you build into the thing itself, not a campaign bolted on afterwards.
5 Pillars of Success
1. Social Currency: people share what makes them look good Sharing is self-presentation. People pass along things that make them appear smart, connected, or in the know, so the sharer's status often decides what travels, more than product quality does. Berger calls the lever inner remarkability: take something ordinary and give it a detail worth repeating. Please Don't Tell, a bar with no sign, hidden behind a phone booth inside a New York hot dog shop, spread because knowing about it was a badge. Barclay Prime used the same lever with a $100 cheesesteak built from Kobe beef and truffles; the price was the point, and it bought more attention than any advertisement.
2. Triggers: top of mind means tip of tongue People talk about what is already in their heads. Cues that fire often, such as a daily routine, a day of the week, or a common object, keep a product accessible and prompt conversation long after launch. The cue matters more than the message. Kit Kat linked its candy to coffee, a drink millions of people have every morning, and gave itself a reminder that fired daily. Rebecca Black's song "Friday" is played and searched for far more on Fridays than on any other day: the calendar itself became the trigger.
3. Emotion: when we care, we share Arousal, not positivity, drives transmission. Berger's experiments show that high-arousal states such as awe, anger, anxiety, and amusement increase the urge to share, while low-arousal states such as sadness or contentment suppress it. That is why the most-emailed articles he studied were awe-inspiring or infuriating rather than merely pleasant. Susan Boyle's audition on Britain's Got Talent is the standard case: viewers shared the clip because the moment produced awe, and passing it on let them relive the feeling. Content that makes people feel mildly good does not move.
4. Public: built to show, built to grow Observability makes behavior imitable. If people can see others using a product, they treat it as worth using and copy it; when usage stays invisible, adoption remains private and stalls. Berger also points to behavioral residue, the traces left behind that keep advertising after the person walks away. Livestrong wristbands worked on both levels: wearing one announced support for a cause and became a visible social signal, so every buyer recruited the next. Apple's white earbuds and the glowing MacBook lid did the same job: the product advertised itself to everyone in the room.
5. Practical Value and Stories Practical value is news people can use, and useful information gets passed on because it helps someone else at no cost to the sender. Ken Craig, an 86-year-old man, filmed himself shucking corn in a microwave in under a minute, and the video kept spreading because it saved people effort. How value is framed also changes whether it feels worth sharing: below $100 a percentage discount looks larger, above $100 a dollar figure does.
Stories are the delivery vehicle. Facts are forgettable; narratives survive retelling, and a brand written into the plot cannot be removed when the story is passed on. Berger calls this the Trojan horse. Subway's Jared campaign worked exactly that way: a man loses weight eating Subway sandwiches, and anyone repeating the story has to say Subway.
Key Takeaway
"Virality isn't born, it's made. Products catch on when they trigger psychological transmission drivers."
Practical Task
1. Choose one asset you are about to launch and write, in one sentence, what it is and who it is for. 2. Write the sentence a customer would use to tell a friend, one that makes the teller look sharp. If you cannot, add a remarkable detail or insider access. 3. List the moments your customer already has every day, then attach your product to the most frequent one. Repeat the same link in every message so the cue sticks. 4. Pick one high-arousal emotion and make the first three seconds of your message deliver it. Delete anything that only produces mild interest. 5. Make usage visible: a badge, a sticker, a wristband, a shared artifact, or a public marker that survives after the user leaves. 6. Turn your single most useful tip into a short story with your brand inside the plot. If the story still works with your name removed, rewrite it. 7. Test on ten people from the target group. Count how many retell it unprompted within a week and which trigger they repeat. Keep the trigger they actually used.