What's the Curse of Knowledge, and How Can You Break It?

Imagine you are a political speechwriter, and your boss — the candidate — is confronting a challenging issue that has just arisen in the national news. She asks you to draft a speech in which she presents her opinion to the world You agree, and you sit down to write. But there's a problem: you’re not sure whether your boss is in favor of the issue, or against it. You review her messages, and it’s clear that she believes she’s told you exactly what she wants, but somehow the task remains vague. How exactly did this go wrong?

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Let’s try another example: You ask your partner to pick a local restaurant and pick up some take-out, this evening. Then, while logging in to a Zoom meeting, you also ask your partner to buy some wine on their way home. While your partner follows through on your requests, you are left astounded and annoyed: How is it that they could pick a restaurant that was involved in a health scandal last month? And why would they choose a type of wine you hate?

Both you and the political candidate, above, have fallen afoul of a psychological effect known as the curse of knowledge. It’s a simple but devastating effect: Once we know something, it’s very difficult to imagine not knowing it, or to take the perspective of someone who doesn't. The effect was first isolated by Elizabeth Newton, a Ph.D. candidate at Stanford, in 1990. Newton arranged an experiment in which one person — a “tapper” — was asked to tap out the melody of a popular song, while another person — the “listener” — was asked to identify it. The tappers assumed that their listeners would correctly identify about 50% of their melodies; they were amazed to learn that the listeners only got about one out of 40 songs correct. To the tappers, their melodies sounded perfectly clear and obvious, but the listeners heard no music, no instrumentation in their heads — only the muffled noise of a finger tapping on a table.

Now let's go back to the second example, above. You may hold a certain set of assumptions and biases about restaurants and wine: You know a few things about which vintners have recently received critical attention and which restaurants in your area make the highest-rated dishes. But you did not communicate any of this information to your partner; you simply assumed, automatically, that she would be aware of it. It may even have seemed obvious that everyone would know as much as you do about local restaurants. In making these decisions without clear input, then, your partner was limited to their own information, assumptions, and biases. They couldn’t know what you wanted, or which way you were leaning.

What can we do to lift the curse? The answer is as simple as you think: improved communication. As I noted in a post about the Dunning-Kruger effect last year, people who aren't well-informed are nevertheless quite likely to feel confident in their opinions, because they don’t know enough to question their own unearned confidence. Similarly, the unrecognized assumption that your partner knows your mind, or can premise their opinions on information you haven't communicated, is likely to leave you feeling as though you've been clear about your wants and needs when you haven’t. In that post, I recommended questioning your own assumptions and certainties, to make sure your decisions are not limited by concepts you haven’t yet learned — or even by unconscious processes: Evading the curse of knowledge works in a similar way. Whenever you assume that something is obvious to all parties, you’re likely to leave yourself open to ambiguity.

Instead, try to slow down your communication, avoid assumptions, and empathize with the person to whom you’re speaking. Ask yourself if they would really know what you're talking about, and if they really are as familiar with the topic as you are. Think about the smaller skills and facts that need to be understood, too, not just the main point. To break the curse, you’ll have to work a little bit harder, put yourself in the other person's shoes, and think a little bit more carefully as you speak.