Contagious: Why Things Catch On

by Jonah Berger

Word of mouth is the primary factor behind 20 percent to 50 percent of all purchasing decisions.

Word of mouth is more effective than traditional advertising for two key reasons. First, it’s more persuasive.

Second, word of mouth is more targeted.

Word of mouth, on the other hand, is naturally directed toward an interested audience.

Research by the Keller Fay Group finds that only 7 percent of word of mouth happens online.

Principle 1: Social Currency

Principle 2: Triggers

Principle 3: Emotion

Principle 4: Public

Principle 5: Practical Value

Principle 6: Stories

Because behavior is public and thoughts are private.

simple way to figure out which discount frame seems larger is by using something called the Rule of 100. If the product’s price is less than $100, the Rule of 100 says that percentage discounts will seem larger. For a $30 T-shirt or a $15 entrée, even a $3 discount is still a relatively small number. But percentagewise (10 percent or 20 percent), that same discount looks much bigger. If the product’s price is more than $100, the opposite is true. Numerical discounts will seem larger. Take a $750 vacation package or the $2,000 laptop. While a 10 percent discount may seem like a relatively small number, it immediately seems much bigger when translated into dollars ($75 or $200). So when deciding how good a promotional offer really is, or how to frame a promotional offer to make it better, use the Rule of 100. Think about where the price falls relative to $100 and how that shifts whether absolute or relative discounts seem more attractive.

And that is the magic of stories. Information travels under the guise of what seems like idle chatter.

The same six principles, or STEPPS, drive things to catch on. Social Currency We share things that make us look good Triggers Top of mind, tip of tongue Emotion When we care, we share Public Built to show, built to grow Practical Value News you can use Stories Information travels under the guise of idle chatter

Social Currency Does talking about your product or idea make people look good? Can you find the inner remarkability? Leverage game mechanics? Make people feel like insiders? Triggers Consider the context. What cues make people think about your product or idea? How can you grow the habitat and make it come to mind more often? Emotion Focus on feelings. Does talking about your product or idea generate emotion? How can you kindle the fire? Public Does your product or idea advertise itself? Can people see when others are using it? If not, how can you make the private public? Can you create behavioral residue that sticks around even after people use it? Practical Value Does talking about your product or idea help people help others? How can you highlight incredible value, packaging your knowledge and expertise into useful information others will want to disseminate? Stories What is your Trojan Horse? Is your product or idea embedded in a broader narrative that people want to share? Is the story not only viral, but also valuable?