Tit-for-Tat Strategy

A repeated-game strategy that begins with cooperation and subsequently copies the partner’s previous move.

Tit-for-tat cooperates on the first round, then copies the partner’s previous action. It can sustain mutual cooperation with a cooperative partner, respond to defection, and return to cooperation after the partner does. Anatol Rapoport’s submitted program won Axelrod’s influential tournaments under their particular participants, rules, and scoring system.

That result does not make tit-for-tat the universally optimal strategy for repeated interaction. Opponent mix, errors, game length, payoffs, and the definition of success matter. Two tit-for-tat players can echo an accidental mismatch back and forth; if both end up defecting together, neither automatically initiates repair. Practical relationships also contain negotiation, changing needs, and ambiguous actions absent from the simple game.

When to use it

Useful for studying repeated cooperation and comparing explicit reciprocal strategies.

How it can help

Examine conditional reciprocity, observability, and how a response rule handles mistakes.