The curse of knowledge (or "how can you not know that!")

A recent article in the New York Times, referred to the curse of knowledge summarised nicely by the example below:

This so-called curse of knowledge, a phrase used in a 1989 paper in The Journal of Political Economy, means that once you’ve become an expert in a particular subject, it’s hard to imagine not knowing what you do. Your conversations with others in the field are peppered with catch phrases and jargon that are foreign to the uninitiated. When it’s time to accomplish a task — open a store, build a house, buy new cash registers, sell insurance — those in the know get it done the way it has always been done, stifling innovation as they barrel along the well-worn path.

Elizabeth Newton, a psychologist, conducted an experiment on the curse of knowledge while working on her doctorate at Stanford in 1990. She gave one set of people, called “tappers,” a list of commonly known songs from which to choose. Their task was to rap their knuckles on a tabletop to the rhythm of the chosen tune as they thought about it in their heads. A second set of people, called “listeners,” were asked to name the songs.

Before the experiment began, the tappers were asked how often they believed that the listeners would name the songs correctly. On average, tappers expected listeners to get it right about half the time. In the end, however, listeners guessed only 3 of 120 songs tapped out, or 2.5 percent.

The tappers were astounded. The song was so clear in their minds; how could the listeners not “hear” it in their taps?

I certainly know that experience and as Chris Tarrant says on Who Wants to be a Millionairre "It's only easy when you know the answers". Indeed.