It’s hard to be
a tapper

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I still remember my surprise the first time I tried it myself.

It was a workshop for university teachers. I asked one of the participants to step out into the corridor with me and gave her the instructions: we’ll play “Name That Tune”, you’ll tap “Happy Birthday” on the desk with your hand, and before we go back in, write down on a piece of paper what percentage of the room will guess it. She wrote 60%. We went back in. She tapped confidently, in a steady rhythm, with a slight smile, because everyone knows “Happy Birthday”. When she finished, I asked everyone who knew the song to raise a hand. One person did.

I knew this result from the literature, and still I watched in disbelief. The experiment was first run by Elizabeth Newton for her doctorate in psychology at Stanford University. Across 120 attempts, listeners guessed 3 songs, which is 2.5%. And the predictions? The tappers expected listeners to recognise half of them.

It’s hard to be a tapper – write Chip and Dan Heath in their book “Made to Stick”.

The tapper hears the whole melody in their head and can’t switch it off. That is why they can’t imagine that the listener only gets single, disconnected knocks. This is the so-called curse of knowledge: once we know something, we lose access to the state in which we didn’t know it yet.

And this experiment plays out every day, just without the desk and without “Happy Birthday”. We tap when we present an idea we’ve worked on for weeks, when we explain a task to our team, or when we show someone a solution that seems obvious to us. And it hits hardest those who explain things for a living. University teachers spend years with their subject, they see the whole structure of the lecture, they know what each example is for and where each slide leads. The better we know our subject, the louder the melody plays, and the harder it is to hear what actually reaches the room.

Our own melody is hard to silence, but we can regularly check what gets through. In class, you can use the Muddiest Point, a technique described by Frederick Mosteller of Harvard University. At the end of a session, students anonymously answer one question: what was least clear today? A sheet of paper or a short online form and a moment at the end of class are enough. The answers show exactly where the room heard only knocking, and they tell you where to start next time.

PS. Tapping also works brilliantly as a warm-up: one person in the corridor, one slip of paper and one birthday song. After a start like that, the conversation about communication goes very differently.

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Sources
C. Heath, D. Heath, Made to Stick: Why Some Ideas Survive and Others Die, Random House (2007).
F. Mosteller, The ‘Muddiest Point in the Lecture’ as a Feedback Device, On Teaching and Learning: The Journal of the Harvard-Danforth Center, 3 (1989).
E. L. Newton, Overconfidence in the Communication of Intent: Heard and Unheard Melodies, doctoral dissertation, Stanford University (1990).