Motivated exposition

Motivated exposition is background information delivered at a moment when a character has a genuine reason to say, think or discover it, so the reader absorbs it as a by-product of the scene rather than as an announcement.

The unmotivated version is easy to recognise: "As you know, Bob, the reactor has been unstable since the war." Nobody tells a colleague what that colleague already knows. The line exists for the reader, and the reader can feel it.

The motivated versions all supply a reason for the words to be spoken. Someone present genuinely does not know, and asks. A character uses the fact as a weapon in an argument, so the information arrives as an accusation. The reader finds it in a document, or meets it as a consequence before anyone explains it.

A quick test: delete the exposition and ask whether the scene still has a reason to exist. If its only job was to deliver the fact, it was not motivated — it was a lecture with furniture.

Timing matters as much as motive. Information is most welcome just after the reader starts wanting it. Withhold a beat longer than feels comfortable, and the explanation lands as relief rather than homework.