Why Things Catch On

What makes things popular?

Word of mouth is 10 times as effective as traditional advertising, but why do people talk about and share certain things rather than others? Why do some products catch on, some ideas diffuse, and some online content go viral?

Wharton professor Jonah Berger has spent the last decade answering these questions. In Contagious, Berger reveals the secret science behind word-of-mouth and social transmission. Discover how six basic principles drive all sorts of things to become contagious, from consumer products and policy initiatives to services and ideas within organizations.

Contagious combines groundbreaking research with powerful stories. Learn how a luxury steakhouse found popularity through the lowly cheese-steak, why anti-drug commercials might have actually increased drug use, and why more than 200 million consumers shared a video about one of the seemingly most boring products there is: a blender. If you’ve wondered why certain stories get shared, e-mails get forwarded, or videos go viral, Contagious explains why, and shows how to leverage these concepts to craft contagious content. This book provides a set of specific, actionable techniques for helping information spread—for designing messages, advertisements, and information that people will share. Whether you’re a manager at a big company, a small business owner trying to boost awareness, a politician running for office, or a health official trying to get the word out, Contagious will show you how to make your product or idea catch on.


An easy, breezy read, peppered with absorbing examples…If there was a “like” button underneath it, you’d probably find yourself clicking it. –Financial Times

Entertaining, illustrative examples in the vein of Malcolm Gladwell or Freakonomics. –Kirkus

Contagious provides…interesting insights into factors that can help make an idea, a video, a commercial or a product become infectious –New York Times

Berger writes in a sprightly, charming style that deftly delineates the intersection of cognitive psychology and social behavior with an eye toward helping businesspeople and others spread their messages. –Publishers Weekly

Contagious contains arresting — and counterintuitive — facts and insights. –The Boston Globe

The book is just plain interesting. Berger’s cases are not only topical and relevant, but his principles seem practical and are easily understood –The Christian Science Monitor

Contagious explains secret behind infectious ideas –USA Today

A playbook for marketers –Fast Company Unassigned


Translations of Contagious