"You only use 10 percent of your brain" is an urban legend, just like many others you've probably heard: The organ thieves who steal the kidneys of unsuspecting travelers. The gang members who drive on roadways with their lights off, then kill the first driver who flashes his lights at them. The McDonald's executives who secretly support the Church of Satan.

Because urban legends are false ideas that have gained broad acceptance as truth, it's worth studying them as ideas. Why do these ideas succeed while other ideas fail? After all, the urban legends are competing for "brainspace" with all sorts of other ideas, from the profound to the mundane: details of the new Medicare plan, the latest celebrity gossip, the news from Iraq, the day's list of to-dos, and scads of others. Urban legends are "sticky" ideas-they are understand-able and memorable and they change attitudes and behavior. What makes these false ideas so sticky?

In our book Made to Stick: Why Some Ideas Survive and Others Die, we analyze why urban legends succeed in the marketplace of ideas. More importantly, we study what can be learned from urban legends-and other successful ideas-that can help you make your own ideas stick, whether you're communicating with the press, the public, or members of your association.

What Successful Ideas Have in Common

What we realized, in studying urban legends, is that they share a common structure. For instance, urban legends almost always reveal something surprising: You only use 10 percent of your brain! (Wow, think how much smarter I'd be if I could use 25 percent!) Urban legends are always chock full of concrete, sensory images: The guy who wakes up in a bathtub full of ice-missing a kidney! The Kentucky Fried Rat! (Don't ask.) And urban legends are almost always told as sto-ries: A friend of friend of mine told me about the time when …

Urban legends are fascinating, as a class of ideas, because they stick naturally. There are no resources behind urban legends-no ad budgets, no PR flacks, no spin doctors. They are ideas that spread and stick on their own merits. Why? Because they share a common anatomy. They share a common set of traits that make them more likely to stick.

And here's the real whopper of a twist: It's not just urban legends that share these traits. It's every kind of successful idea-proverbs, public health campaigns, political slogans, high school history lessons, sermons, and mission statements. Sticky ideas of all kinds share a handful of traits. Urban legends derive their strength from these principles-but so do true, useful ideas. There are six principles that unite sticky ideas-but before we unpack them, let's look at a real-world sticky idea in action. A classic example comes from the early 1990s, when a man named Art Silverman changed the nation's snacking habits with a single sticky idea.

A Valuable Idea That Looks Like an Urban Legend

In 1992, a man named Art Silverman was struggling with how to create a message that would stick with the American public. Silverman worked for the Center for Science in the Public Inter-est, a nonprofit group that educates the public about nutrition. CSPI's leaders had become suspi-cious about the nutritional profile of movie popcorn. To test their suspicions, they sent bags of movie popcorn, from a dozen theaters in three major cities, to a lab for nutritional analysis. The results surprised everyone.

The USDA recommends that a normal diet contain no more than 20 grams of saturated fat each day. According to the lab results, the typical bag of popcorn had 37 grams.

The culprit was coconut oil, which theaters used to pop their popcorn. Coconut oil had some big advantages over other oils. It gives popcorn a nice, silky texture. It released a more pleasant and natural aroma than the alternative oils. Unfortunately, as the lab results showed, coconut oil was also brimming with saturated fat.

The single serving of popcorn on Silverman's desk-a snack someone might scarf down be-tween meals-had nearly two days' worth of saturated fat. And those 37 grams of saturated fat were packed into a medium size serving of popcorn. No doubt a decent-sized bucket could have cleared triple digits.

His job was to figure out a way to communicate this message to the unsuspecting moviegoers of America. The challenge, Silverman realized, was that few people know what "37 grams of saturated fat" means. Most of us don't memorize the USDA's daily nutrition recommendations. Is 37 grams good or bad? And even if we have an intuition that it's bad, we'd wonder if it was "bad bad"-like cigarettes-or "normal bad"-like a cookie or a milkshake.

Even the phrase "37 grams of saturated fat," by itself, was enough to cause most people's eyes to glaze over. Silverman said, "Saturated fat has zero appeal. It's dry, it's academic, who cares?"

The focus on the statistic-37 grams-was too rational somehow. The amount of fat in this popcorn was, in some sense, not rational. It was ludicrous. The CSPI needed a way to shape the message in a way that fully communicated the ludicrousness. Silverman came up with a solution that emulated some of the best traits of urban legends-while spreading truth.

The CSPI called a press conference on Sept. 27, 1992. Here's the message they presented: "A medium-sized 'butter' popcorn at a typical neighborhood movie theater contains more artery-clogging fat than a bacon and eggs breakfast, a Big Mac and fries for lunch, and a steak dinner with all the trimmings-combined!"

The CSPI didn't neglect the visuals-they laid out the full buffet of greasy food for the tele-vision cameras. An entire day's worth of unhealthy eating, displayed on a table. All that satu-rated fat-stuffed into a single bag of popcorn.

The story was an immediate sensation, featured on CBS, NBC, ABC and CNN. It made the front pages of USA Today, The Los Angeles Times and The Washington Post's Style section. Leno and Letterman cracked jokes about fat-soaked popcorn, and headline writers trotted out some doozies: "Popcorn Gets an 'R' Rating," "Theater Popcorn is Double Feature of Fat," "Lights, Action, Cholesterol!"

The idea stuck. Repulsed theatergoers avoided popcorn in droves. Sales plunged. The service staff at movie houses grew accustomed to fielding questions about whether the popcorn was popped in the "bad" oil. Soon after, most of the nation's biggest theater chains-including United Artists, AMC, and Loews-announced they would stop using coconut oil.

The Six Principles of Sticky Ideas

As we pored over hundreds of sticky ideas like this one, we saw, over and over again, the same six principles at work. As an example, Silverman's idea had 5 of the 6 principles (everything except the Story format):

Principle 1: Simplicity. How do we find the essential core of our ideas? A successful de-fense lawyer says, "If you argue ten points, even if each is a good point, when they get back to the jury room, they won't remember any." To strip an idea down to its core, we must be masters of exclusion. We must relentlessly prioritize. Saying something short is not the mission-sound bites are not the ideal. Proverbs are the ideal. We must create ideas that are both simple and pro-found. The Golden Rule is the ultimate model of simplicity: A one-sentence statement so pro-found that a person can spend a lifetime learning to follow it.

Principle 2: Unexpectedness. How do we get our audience to pay attention to our ideas, and how do we maintain their interest when our ideas take time to understand? We need to violate people's expectations. We need to be counter-intuitive. Consider Art Silverman's message: This wimpy bag of popcorn has the same amount of saturated fat as a daylong feast of fattiness! We can use surprise-an emotion whose function is to increase alertness and cause focus-to grab people's attention. But surprise doesn't last-for our idea to endure, we must generate interest and curiosity. How do you keep meeting attendees engaged for the eighth hour of the day or the fourth day of the conference? We can engage people's curiosity, over a long period of time, by systematically opening gaps in their knowledge-making them aware that they don't know the answer to a compelling question-and then filling those gaps.

Principle 3: Concreteness. How do we make our ideas clear? We must explain our ideas concretely: in terms of what people do and what they can see and touch. Art Silverman nailed concreteness by putting the actual food on display for the media to see. Business communica-tion, on the other hand, is notoriously non-concrete. Mission statements, synergies, strategies, visions-they are often abstract to the point of meaninglessness. Naturally sticky ideas are full of concrete images-kidney thieves, Kentucky Fried rats-because our brains are wired to remem-ber concrete data. In proverbs, abstract truths are often encoded in concrete language: "A bird in hand is worth two in the bush." Speaking concretely is the only way to ensure that our idea means the same thing to everyone in our audience.

Principle 4: Credibility. How do we make people believe our ideas? When former Surgeon General C. Everett Koop talks about a public health issue, most people accept his ideas without skepticism. But, in most day-to-day situations, we don't enjoy this authority. Sticky ideas have to carry their own credentials. We need ways to help people test our ideas for themselves-a "try before you buy" philosophy for the world of ideas. When we are trying to build a case for some-thing, most of us instinctively grasp for hard numbers. But in many cases, this is exactly the wrong approach. In the sole U.S. presidential debate in 1980 between Ronald Reagan and Jimmy Carter, Reagan could have cited innumerable statistics demonstrating the sluggishness of the economy. Instead, he asked a simple question that allowed voters to test for themselves: "Before you vote, ask yourself if you are better off today than you were four years ago."

Principle 5: Emotions. How do we get people to care about our ideas? We make them feel something. Research shows that people are more likely to make a charitable gift to a single, needy individual than to an entire region with enormous statistical need. We are wired to feel things for people, not abstractions. Sometimes the hard part is finding the right emotion to har-ness. For instance, it's hard to get teenagers to quit smoking by instilling fear of the conse-quences, but it's easier to get them to quit by tapping into their resentment of the duplicity of Big Tobacco.

Principle 6: Stories. How do we get people to act on our ideas? We tell stories. Firefighters naturally swap stories after every fire, and by doing so they multiply their experience; after years of hearing stories, they have a richer, more complete mental catalog of critical situations they might confront during a fire and the appropriate responses to those situations. Research shows that mentally rehearsing a situation helps us perform better when we encounter that situation in the physical environment. Similarly, hearing stories act as a kind of mental flight simulator, pre-paring us to respond more quickly and effectively.

Those are the six principles of successful ideas. To summarize, here's our checklist for creat-ing a successful idea: a Simple Unexpected Concrete Credentialed Emotional Story. A clever observer will note that this sentence can be compacted into the acronym SUCCESs. (This is sheer coincidence, of course.)

We all know there are ideas that stick naturally-urban legends, conspiracy theories, and gossip, for instance. But the traits of these schlocky ideas can be co-opted and used to help spread true, useful ideas. Art Silverman at the CSPI took the idea that movie popcorn was gro-tesquely unhealthy and he made it stick. And you and your association can use the same six prin-ciples to make your own ideas stick.