The Curse of Knowledge
Why does a brilliant expert so often explain badly the very thing they have mastered? The answer fits in one phrase: the curse of knowledge. Once you know something, you become unable to imagine what it's like not to know it. Your knowledge blinds you to the other person's ignorance — and it is obstacle number one to a clear explanation.
"The main cause of incomprehensible prose is not laziness or dishonesty but the curse of knowledge: the difficulty of imagining what it's like for someone else not to know something that you know." — Steven Pinker, The Sense of Style (2014)
An experiment that changed everything
In 1990, psychologist Elizabeth Newton ran a now-famous experiment at Stanford. "Tappers" tapped out the rhythm of a well-known song (for example Happy Birthday); "listeners" had to guess the tune. Before listening, the tappers estimated that 50% of listeners would get it. In reality, only 2.5% did (3 out of 120).
Why this dizzying gap? Because the tapper hears the melody in their head while tapping. It is impossible for them to imagine what the other person hears: a string of disjointed, meaningless taps. That is exactly what happens when an expert speaks: they "hear" all the context, the definitions, the implied steps. The listener receives only sharp taps — jargon.
Where the term comes from
The concept was named by economist Robin Hogarth, then studied experimentally by Colin Camerer, George Loewenstein and Martin Weber in a foundational 1989 article (Journal of Political Economy). They showed that better-informed agents cannot "forget" their information in order to predict the behaviour of less-informed agents: knowledge, once acquired, cannot be switched off at will. Brothers Chip and Dan Heath made it, in Made to Stick (2007), the great enemy of all memorable communication.
How the curse shows up
| Symptom | What the expert does | What the listener experiences |
|---|---|---|
| Jargon | Uses trade terms without defining them | Tunes out at the first unknown word |
| Logical leaps | Skips the "obvious" steps | Loses the thread, doesn't dare say so |
| Abstraction | Stays in general concepts | Has nothing concrete to hold onto |
| Too much detail | Wants to say everything, for accuracy | Drowns, retains nothing |
The trap is cruel: the more competent you are, the more exposed you are. The expert does not choose to be obscure — they simply don't see that they are.
Say this / don't say that
- Don't say: "It's obvious, just apply the theorem." (the obviousness is in your head, not the other person's)
- Say: "Let's start from the beginning. What do you already know about this?" (calibrate before explaining)
Practical exercise
Pick a concept you have completely mastered in your field. Explain it out loud in 90 seconds, then reread your transcript, highlighting every word or idea that assumes prior knowledge. You'll be surprised how many "sharp taps" you produce without hearing the melody that accompanies them in your head.
Summary
The curse of knowledge is the inability, once you know, to put yourself back in the shoes of someone who doesn't. Elizabeth Newton's tappers-and-listeners experiment (2.5% success against an expected 50%) illustrates it perfectly; the work of Camerer, Loewenstein and Weber (1989) and the popularization by Pinker and the Heath brothers made it the great obstacle to clarity. It shows up as jargon, logical leaps, abstraction and excess detail. The good news: naming it is already the start of beating it.