Teach It Back

Understanding feels different from recognizing. You can read an idea three times, nod along, and still be unable to explain it. Psychologists call this the illusion of explanatory depth: we think we understand until asked to spell out how something works.

Teaching it back is a simple test. Pick an idea and explain it to a beginner in about five sentences without jargon. Where you stumble, skip a step or reach for a label in place of a reason, you have found a gap. Go back to the source, fill the gap, and try again in simpler words.

The aim is not to perform. It is to find out what you do not yet know, while it is cheap to find out. Even explaining aloud to an empty room works.

The opportunity cost

Maya has read about opportunity cost and can say the phrase. Asked by her brother what it means, she says, “It’s what you give up,” and then cannot say what it would look like for his Saturday.

She goes back, finds the missing step, and tries again: “If you spend Saturday at the game, the cost is the other things you could have done with it, like the trip you wanted.” Her brother nods. Now she can see the idea, not only the phrase.

Try this today Explain one idea from this course to someone new in five plain sentences, and note where you stumble.