Social Currency: Make people look good by sharing
People share things that make them appear smart, cool, or in-the-know to others.
Book summary
Perennial SellerGoodreads Favorite
Contagious
by Jonah Berger
Unlocking the science behind why products, ideas, and behaviors become popular
Why things catch on through word-of-mouth and social influence
4.1(8.5k)Published 2013
Topics
MarketingPsychologySocial InfluenceWord-of-Mouth
Reading companion
How to read Contagious with Readever
Read this book with specific marketing goals in mind, using Readever to highlight STEPPS principles that apply to your projects. Focus on understanding each principle individually before combining them. Use the AI to analyze your existing content against the STEPPS framework and generate ideas for making it more shareable. Apply the concepts to real campaigns as you read.
Things to know before reading
- Familiarize yourself with basic marketing concepts like word-of-mouth and social proof
- The STEPPS framework (Social Currency, Triggers, Emotion, Public, Practical Value, Stories) is central to the book
- Be prepared to analyze real-world examples of viral content through Berger's framework
- Consider how these principles apply beyond marketing to ideas, behaviors, and social movements
Brief summary
Contagious in a nutshell
Contagious reveals the science behind why some products, ideas, and behaviors become popular while others fade away. Based on years of research, Jonah Berger identifies six key principles—the STEPPS framework—that drive social transmission and word-of-mouth. From viral videos to bestselling products, these psychological triggers explain what makes content shareable and memorable.
Key ideas overview
Contagious summary of 6 key ideas
The STEPPS framework reveals six psychological principles that drive word-of-mouth and social transmission.
Triggers: Link your idea to everyday contexts
Products and ideas that are top-of-mind get talked about more frequently.
Emotion: Focus on high-arousal feelings
When we care, we share—emotional content is more likely to go viral.
Public: Make private things observable
Built to show, built to grow—observable products get imitated.
Practical Value: Share useful information
News you can use—people like to help others by sharing practical tips.
Stories: Information travels under the guise of idle chatter
People don't just share information, they share stories—embed your message in narratives.
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Book summaries like Contagious
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Make your ideas, products, and messages impossible to ignore.
This summary gives you the STEPPS framework—a proven system for designing contagious content that people naturally want to share. You'll learn how to leverage social currency, triggers, emotion, public visibility, practical value, and stories to boost your marketing effectiveness and organic reach.
Deep dive
Key ideas in Contagious
Key idea 1
Social Currency: Make people look good by sharing
People share things that make them appear smart, cool, or in-the-know to others.
Social currency refers to the psychological value people gain from sharing information that enhances their social status. Berger shows how remarkable products, insider knowledge, and gamification create talking points that boost sharers' reputations. The key insight: people don't just share useful information—they share information that makes them look useful, interesting, or connected.
Remember
- Design remarkable features that give people something to talk about
- Create insider knowledge or exclusivity that makes sharers feel special
- Use game mechanics like points or status levels to encourage sharing
Key idea 2
Triggers: Link your idea to everyday contexts
Products and ideas that are top-of-mind get talked about more frequently.
Triggers are environmental cues that remind people of related products or ideas. Berger demonstrates how Kit Kat's association with coffee breaks and Rebecca Black's "Friday" song became weekly reminders. The most effective triggers are frequent, occur in contexts where people talk, and naturally connect to the product. Top-of-mind equals tip-of-tongue.
Remember
- Connect your product to frequent events or environments
- Design triggers that occur where people naturally converse
- Ensure the connection between trigger and product feels natural
Key idea 3
Emotion: Focus on high-arousal feelings
When we care, we share—emotional content is more likely to go viral.
Berger distinguishes between high-arousal emotions (awe, excitement, anger, anxiety) that drive sharing and low-arousal emotions (contentment, sadness) that don't. The key insight is that physiological arousal—not just valence—determines sharing behavior. Content that evokes strong emotional responses gets shared because arousal drives action.
Remember
- Focus on high-arousal emotions like awe, excitement, or anger
- Use storytelling to create emotional connections with your audience
- Avoid content that evokes contentment or mild sadness
Key idea 4
Public: Make private things observable
Built to show, built to grow—observable products get imitated.
Public visibility creates social proof and facilitates imitation. Berger shows how Apple's white earbuds, Livestrong bracelets, and Hotmail signatures made private behaviors public. When people can see others using a product or adopting a behavior, they're more likely to follow suit. Making the invisible visible is key to social epidemics.
Remember
- Design products that are visibly distinctive when used
- Create behavioral residue that others can observe
- Make private adoption publicly observable
Key idea 5
Practical Value: Share useful information
News you can use—people like to help others by sharing practical tips.
Practical value drives sharing because people enjoy helping others. Berger explains how useful content—from money-saving tips to life hacks—gets passed along. The key is making the practical value obvious and easy to communicate. When content saves time, money, or improves lives, people feel good about sharing it.
Remember
- Highlight clear, specific benefits in your messaging
- Make useful information easy to understand and apply
- Emphasize how your content helps others solve problems
Key idea 6
Stories: Information travels under the guise of idle chatter
People don't just share information, they share stories—embed your message in narratives.
Stories are the original viral vehicles. Berger shows how narratives carry ideas in memorable, engaging packages. The key is creating stories that naturally incorporate your message or product—what he calls "valuable virality." When the story is compelling, the embedded message gets transmitted along with it.
Remember
- Build narratives around your product or idea
- Ensure your message is integral to the story, not tacked on
- Create stories people will want to retell in their own words
Context
What is Contagious about?
Contagious: Why Things Catch On is a groundbreaking exploration of the psychological and social factors that drive word-of-mouth and social transmission. Drawing on extensive research in marketing, psychology, and sociology, Jonah Berger reveals why some products, ideas, and behaviors become popular while others don't.
The book introduces the STEPPS framework—six principles that explain social epidemics: Social Currency, Triggers, Emotion, Public, Practical Value, and Stories. Through compelling case studies and rigorous analysis, Berger shows how these principles work together to make content contagious, from viral videos to bestselling products and social movements.
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Review
Contagious review
Berger's writing combines academic rigor with practical accessibility, making complex psychological concepts understandable and actionable. The STEPPS framework provides a systematic approach to understanding and creating contagious content, backed by compelling research and real-world examples.
Critical Reception: Contagious became a New York Times bestseller with over 1 million copies sold worldwide and has been translated into more than 30 languages. The book won the prestigious American Marketing Association's Berry-AMA Book Prize and has been adopted as essential reading in business schools and marketing departments globally. Major corporations from Fortune 500 companies to Silicon Valley startups have implemented Berger's framework to drive organic growth and word-of-mouth marketing.
- *New York Times* bestseller with over 1 million copies sold
- Translated into more than 30 languages
- Featured in *The New Yorker*, *Harvard Business Review*, and *Fast Company*
- STEPPS framework adopted by Fortune 500 companies and startups
- Winner of the American Marketing Association's Berry-AMA Book Prize
- Essential reading for marketing professionals and entrepreneurs
Who should read Contagious?
Marketers and advertisers looking to boost organic reach
Entrepreneurs and startup founders building brand awareness
Content creators and social media managers
Product managers designing shareable features
Anyone interested in psychology of social influence
About the author
Jonah Berger is a marketing professor at the Wharton School of the University of Pennsylvania and a world-renowned expert on social influence, word-of-mouth, and consumer behavior. He has published dozens of articles in top-tier academic journals and popular outlets, and his research has been featured in The New York Times, Wall Street Journal, and Harvard Business Review.
Berger received his PhD from Stanford University's Graduate School of Business and has been recognized with numerous awards for his research and teaching, including the Early Career Award from the American Marketing Association. His consulting clients include major corporations like Google, Coca-Cola, and General Motors. In addition to Contagious, he is the author of Invisible Influence and The Catalyst, continuing his exploration of how social forces shape individual behavior and decision-making.
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Final summary
Contagious provides a science-backed framework for understanding why some ideas spread while others don't. The STEPPS principles offer a systematic approach to designing products, messages, and experiences that people naturally want to share. By leveraging social currency, triggers, emotion, public visibility, practical value, and stories, you can make your content impossible to ignore and easy to spread.
Inside the book
The STEPPS Framework in Practice
Social Currency Examples
- Hidden restaurants like Please Don't Tell (PDT) create exclusivity through phone booth entrances
- American Express Centurion card (black card) offers status through limited availability
- Frequent flyer programs gamify engagement through status tiers
Trigger Strategies
- Kit Kat and coffee breaks: Associating products with daily routines
- "Friday" by Rebecca Black: Leveraging weekly temporal triggers
- Geico's "15 minutes could save you 15%": Repetitive messaging creates memory triggers
Emotional High-Arousal Content
- Awe: NASA's "Pillars of Creation" images (27M+ Facebook shares)
- Anger: Outrage-inducing political content drives sharing
- Excitement: Product launches and announcements create anticipation
- Anxiety: Warning about potential threats motivates protective sharing
Public Visibility
- Apple's white earbuds: Made private listening public and distinctive
- Livestrong bracelets: Turned cancer support into visible social statement
- Hotmail's signature line: "Get your free email at Hotmail" spread the service
Practical Value
- BuzzFeed's "23 Life Hacks" articles: Actionable tips get shared widely
- Money-saving content: Financial advice spreads through social proof
- Health and wellness tips: Useful information helps others
Story-Based Virality
- Subway's Jared story: Weight loss narrative carried brand message
- Blendtec's "Will It Blend?" videos: Entertainment showcased product capability
- Dove's "Real Beauty" campaign: Stories challenged beauty standards
Implementation Checklist
Before launching content, ask:
- Social Currency: Does it make people look good sharing this?
- Triggers: What will remind people of this content?
- Emotion: Does it evoke high-arousal emotions?
- Public: Is the behavior or product visible to others?
- Practical Value: Does it help people solve problems?
- Stories: Can you embed the message in a compelling narrative?
Common Mistakes to Avoid
- Focusing only on one principle: Most viral content combines multiple STEPPS
- Ignoring context: The same content works differently across platforms
- Overlooking existing triggers: Don't create new associations if existing ones work
- Making content too complex: Simpler messages travel farther
- Forgetting the story: Data alone rarely goes viral
Measuring Contagious Success
Track metrics beyond basic sharing:
- Share velocity: How quickly content spreads
- Engagement depth: Comments, saves, and return visits
- Network reach: How many new audiences discover content
- Behavioral change: Did sharing lead to desired actions?
- Longevity: Does content continue to be shared over time?
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