Generous TFT (Generous Tit For Tat)

Where it comes from

The refinement that outperforms plain Tit For Tat once you allow mistakes into the game. Axelrod's own conclusion after the second tournament pointed this way.

How it plays

Generous Tit For Tat is Tit For Tat with a leak in it, and the leak is the improvement. It answers defections as reliably as the original for the overwhelming majority of the game, and every so often it lets one go without responding. In a world where nothing ever goes wrong by accident, that is a pure and pointless cost.

The moment you allow noise, it becomes the better rule. Two strict copiers who fall into mutual retaliation cannot stop, because each is faithfully answering the last thing that happened, and the whole relationship is spent on a spiral that began with an accident. A strategy that occasionally declines to answer is the mechanism that breaks it, and it only has to fire once.

The cost is honest and worth stating: against a relentless defector, every forgiven defection is a free hit given away. Generosity has a price, it is paid to exactly the opponents who deserve it least, and the case for the rule is that it collects far more from the reciprocators than it hands to the brutes.

In football it is the side that answers everything, then quietly declines to answer one challenge, and turns a fixture that was becoming a war back into a game of football. It is the least dramatic decision in the league and the one most likely to be worth points.

In this league

Almsbury Albion of Almsbury play Generous TFT. That a rule with a little slack in it beats a rule without. They have not played yet this season.