Reciprocity

Reciprocity is the social norm that a favor received creates an obligation to return one. It is among the most reliable regularities in human behavior. Give somebody something of value and they feel a pull to give back, often more than they received and usually without being asked. Every culture studied has a version of it, which is why it works in situations where almost nothing else transfers.

The formal account comes from sociology and social psychology. Alvin Gouldner argued in 1960 that the norm of reciprocity is close to universal and that it stabilizes relationships by making an unrepaid gift uncomfortable to sit with. Robert Cialdini later placed it first among his principles of influence, with the unsolicited flower and the restaurant mint as the standard demonstrations: a small gift measurably raises compliance and tips. Adam Grant's work on givers and takers is the version closest to a career, and its finding is not that giving always wins. It is that giving with no sense at all of the return is what burns people out.

In a professional network reciprocity runs on a long clock and a private ledger. You make an introduction, answer a question, pass on a candidate, read someone's draft. Nothing settles at the time. Months later the person you helped is in a position to help you, and whether they do turns largely on whether the balance still feels roughly even to them. Two things break the loop: asking before you have given anything, and forgetting what you promised, which reads as indifference whether or not it was.

It does not have to be direct. In dense networks reciprocity is usually generalized. You help someone, they help someone else, and your return arrives from a third party who heard you were useful. That is why reputation and reciprocity are hard to separate in practice, and why keeping score out loud backfires. The ledger works precisely because it is private.

The practical difficulty is not willingness. It is recall. Most people intend to return a favor and simply lose the thread, because the promise was made in a conversation six months ago, in a channel they no longer have open, and nothing brings it back to mind. Relationships rarely fail on a refusal. They fail on a promise that quietly expired.