A favor you accepted without noticing is still a debt you owe

Accepting help does not feel like taking on debt, and that is exactly why the debt outlasts the memory of it.

What Cialdini's research found

Robert Cialdini's work on the reciprocity principle is some of the most replicated research in social psychology, the finding, in short, is that receiving something from someone creates a felt obligation to return it, and that obligation persists even when the original favor was small, unsolicited, or long forgotten by the person who received it. The debt does not need to be tracked consciously to be real, and it does not expire on its own.

Why this matters more than it seems

Professional life runs on a version of this constantly, a colleague covering a shift, someone putting in a good word, a favor called in from someone senior who once helped you get a foothold. None of these come with an invoice. All of them get repaid eventually, often at a moment and in a form you did not choose, which is exactly why people who take without ever returning discover, usually at the worst possible time, that the account they assumed was neutral was never actually empty.

Where to start

Think of the last real favor someone did for you at work, not a small courtesy, an actual instance of someone spending real effort or risk on your behalf. If you have not returned anything comparable since, that debt is still open on their side of the ledger, whether or not either of you would describe it that way out loud.

Closing it does not require a grand gesture, often just noticing an opportunity to help them the same way they helped you, and taking it.

Reading which past favors are actually still open, versus which have already been squared through something you have forgotten doing, is a judgment only you can make honestly with yourself. What this gives you is the habit of checking, since the debt does not send a reminder.

There is a specific way to close out an old favor that reads as thoughtful rather than as settling a score, and it is worth doing before it gets called in on someone else's timeline instead of yours.