Reputation as Iterated Signaling¶

Why It Matters¶

One-shot interactions lack credibility - cheap talk dominates. Repeated interactions enable reputation, which solves many signaling problems. Understanding reputation as iterated signaling explains why long-term players behave differently than short-term ones and why reputation loss is so damaging.

The Key Move¶

When evaluating someone's claim or promise, ask: do they have a reputation at stake? How many past interactions built that reputation? What would it cost them to lose it? If they have substantial reputation capital and this interaction is small relative to that capital, their commitment is likely credible. If they're new or leaving the repeated game, discount heavily.

Classic Application¶

Merchant reputation in medieval trade. Without formal contracts or legal enforcement, long-distance trade required trust. Merchants built reputations over decades of reliable dealing. Cheating once would destroy reputation, eliminating future trade opportunities. The future value of reputation exceeded any one-time gain from cheating, making honesty individually rational. Reputation solved the commitment problem without external enforcement.

Surprising Application¶

Online seller ratings (eBay, Amazon, Airbnb). Sellers invest in building five-star ratings through consistent quality. Each transaction adds to reputation stock. This reputation enables higher prices and more sales. Cheating customers might yield short-term profit but destroys reputation, eliminating future business. The platform leverages iterated signaling to solve trust problems in anonymous markets.

Failure Modes¶

End-game problems: when someone is exiting the repeated game (retiring, moving, shutting down), reputation no longer constrains them. The last period is like a one-shot game.
Reputation transfer failure: reputation in one domain may not transfer to another. Just because someone is reliable in X doesn't mean they're reliable in Y.
Cheap reputation: if reputation is easy to abandon and rebuild (create new account, new identity), it loses constraining power. Reputation works only if it's costly to replace.

Go Deeper¶

Kreps & Wilson, "Reputation and Imperfect Information" (Journal of Economic Theory, 1982) - formal model
Greif, "Reputation and Coalitions in Medieval Trade" (Journal of Economic History, 1989) - historical application

Signaling - Information Economics: Reasoning Under Asymmetry and Uncertainty