Via Talks at Google

"What I can guarantee is more people will talk about and share your idea. A useful analogy: think of it like a batting average. Can you guarantee you're going to hit a home run every time? No. But to the degree you can improve your batting average, you're increasing the chance that you get a hit each time. That's what these principles can do. They can increase the chance that people talk about and share your ideas."

— Contagious: Why Things Catch On | Jonah Berger | Talks at Google, watch at 9:50

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Most people treat virality like the weather: unpredictable, unteachable, the kind of thing that happens to other people's products.

Wharton professor Jonah Berger spent years studying why New York Times articles make the most-emailed list, why Cheerios outperforms Disney World in word-of-mouth, and why a song universally mocked as the worst ever recorded got 300 million views.

His conclusion: sharing isn't random. It follows six psychological principles he calls STEPPS — Social Currency, Triggers, Emotion, Public, Practical Value, and Stories. Together, they explain nearly everything about why things catch on, and they're all engineerable.

• Social Currency — People share things that make them look good. The Please Don't Tell speakeasy, hidden behind a phone booth in a hot dog restaurant, became one of NYC's hardest reservations to get without a single ad. Knowing about it confers insider status. Sharing it reinforces that status.
• Triggers — What's top-of-mind is tip-of-tongue. Rebecca Black's "Friday" got 300 million views because it had a weekly environmental reminder. Kit Kat paired with coffee because coffee breaks happen multiple times a day. When someone says peanut butter, we think jelly. Triggers turn a single piece of content into a recurring conversation.
• Emotion — Berger's NYT research found that high-arousal emotions (awe, excitement, anger) drive sharing; low-arousal emotions (sadness, contentment) suppress it. The physiological activation bleeds over into the urge to act, including sharing. Running in place in the lab increased article sharing behavior even when the articles had nothing to do with running.
• Public — We imitate what we can see. Apple flipped its laptop logo to face outward and made its headphones white. Both decisions sacrificed user convenience for public visibility. What stays private can't spread.
• Practical Value — "News you can use." People share useful information to help others, not to advertise. Practical value is distinct from social currency: the latter is about making yourself look good; the former is about the recipient getting value.
• Stories — Try to tell someone a story about the Panda Cheese TV ads without mentioning the brand. You can't. The best shareable content makes the brand inseparable from the narrative.

The STEPPS framework doesn't guarantee virality, but it's a useful diagnostic for why things don't catch on. Most products and ideas score on one or two principles by accident. The ones that consistently spread tend to be engineered across several.

Run your idea against the six principles: Does sharing it make the sharer look good? Does anything in their daily environment remind them of it? Does it activate rather than deactivate? Can others see it? Does it help someone? Can the story be retold? The more boxes you check, the more your batting average for virality goes up.

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Things To Try

Evaluate your current products and messaging

• Audit your product or service: is it inherently frequent (like Cheerios) or infrequent (like Disney)? If infrequent, identify ways to create ongoing triggers.
• List the environmental cues your customers encounter daily or weekly—what do they see, hear, smell in their regular routines?
• Review your marketing messages: do they give people social currency by making sharers look smart, cool, or in-the-know?

Design for triggers

• Identify a frequent environmental cue relevant to your product and build associations (like Kit Kat + coffee).
• Test your trigger frequency: does it occur daily, weekly, monthly, or annually? Optimize for more frequent triggers.
• Consider your customer's specific context—what works in one geography or demographic may fail in another.

Build mechanisms for transmitting stories

• Before creating shareable content, ask: can someone tell this story without mentioning my brand?
• Make your brand name or key message integral to the narrative itself, not just tagged on at the end.
• Test with friends: have them retell your story back to you and see if the brand survives the retelling.

Optimize for public visibility

• Identify ways to make private usage public (like Apple's white headphones).
• Create physical or social signals that make adoption visible to others ("Sent from my iPhone" default email footer).
• Design products or packaging that naturally get seen by people beyond the user.

Craft high-arousal emotional content

• Focus on emotions that activate rather than deactivate: awe, excitement, humor, or even appropriate anger.
• Avoid purely sad or calming content unless your goal is explicitly not to drive sharing.
• Combine practical value with emotional resonance for maximum impact.