The Curse of Knowledge

Why the most common mode of persuasion is often doomed to fail

“SAVI is such a useful tool!”
“You have to try these brownies — they’re delicious.”
“Those pants look kind of silly with those loafers.”
“Terminator 2 is a great date movie.”

Many readers who are familiar with SAVI will easily recognize this type of communication: the opinion. You may even recall that it is the single most widely used communication behavior. Opinions are everywhere. We all have them — about ourselves, people we know, politics, sports, religion, popular culture, and any other topic you can think of. All beliefs, speculations, evaluations, interpretations, and judgments are opinions.

A defining feature of an opinion is that it is never true or false. No amount of research can ever prove or disprove the idea that your new shirt looks lovely on you, that Ulysses is a brilliant novel, or that your boss is a boring old drone; these will forever be matters of individual judgment. However, whenever we believe very firmly in a particular opinion, it’s very easy to see it as true — as a fact.

Now, why do we give so many opinions? And why do they fail so miserably in persuading other people to agree with us? One of the most compelling — and certainly the most dramatic-sounding — answers we’ve found is something called The Curse of Knowledge. This concept comes from the book Made to Stick: Why Some Ideas Survive and Others Die, by Chip and Dan Heath (which we highly recommend).

They give a beautiful illustration of this phenomenon, with a variation of a “name that tune” sort of challenge. In a 1990 study at Stanford, subjects were split up into pairs consisting of one “tapper” and one “listener.” The tapper’s job was to pick one of 25 well-known songs (such as “Happy Birthday to You” or “The Star Spangled Banner”) and tap out the rhythm of that song for the listener; the listener’s job was to guess what song was being tapped out.

As it turns out, the listener’s job is extremely difficult. Out of 120 songs that got tapped out, listeners guessed only 3 correctly (a success rate of 2.5 percent). What was fascinating, though, was that to the tappers, the task didn’t seem nearly so tough. Before the listeners guessed the song, the tappers were asked how likely it was that the guess would be correct. Their response: 50%. So there’s an enormous discrepancy here: The tappers expected their messages to come through 50% of the time, but they actually got through less than 3% of the time.

What accounts for that difference? Try tapping out a song for yourself, and you can easily see (or, rather, hear) what happened. As you tap out the song, you’ll be aware not only of the song’s rhythm (which you’re indicating through tapping), but also of the tune (which is playing only in your head). In fact, it’s impossible to do this task without hearing the tune. This is what happened to the tappers in the study — and because they could hear the tune, it seemed pretty obvious how all the taps went together. They couldn’t imagine what it was like for the listeners, who were just hearing strings of disconnected taps.

As Chip and Dan Heath explain, “This is the Curse of Knowledge. Once we know something, we find it hard to imagine what it was like not to know it. Our knowledge has ‘cursed’ us. And it becomes difficult for us to share our knowledge with others, because we can't readily re-create our listeners' state of mind.” In their book, they relate this problem to all sorts of difficulties in getting a message across. For instance, when a CEO talks to employees about abstract concepts such as “unlocking shareholder value,” “there is a tune playing in her head that the employees can't hear.”

The same principle can help explain why an opinion that seems obviously true and convincing to one person can be entirely unpersuasive to others. Every opinion is the tip of a much larger intellectual and emotional iceberg. When we state only opinions, we’re expressing the bare-bones conclusions we’ve come to (like isolated taps), without all the depth of knowledge and experiences that led us to those conclusions (the tunes in our head).

For instance, for a person with a strong belief that U.S. healthcare should include a public insurance option, the tune might include any number of personal experiences with insurance and health services, stories from friends and acquaintances, and knowledge gained from articles, television programs, and other media reports on the subject. When this person tells his opinion to others, there’s no guarantee that his listeners are hearing a similar tune. In fact, what often happens is that different people hear conflicting tunes based on completely divergent experiences. (For instance, a personal history and knowledge base that point to the dangers of a public insurance option.) So it should come as no surprise that much of the time, we all end up coming to different conclusions and getting into arguments over our competing opinions.

What’s the solution? Stay tuned for the next post!

(In the meantime, you can read excerpts from Made to Stick at http://www.madetostick.com/excerpts/. Search for “tappers” to find the study we’ve been discussing here.)