Tit for tat - Wikipedia, the free encyclopedia

1. 'Unless provoked, the agent will always cooperate'
2. 'If provoked, the agent will retaliate'

These are the first two moves in Rapoport's tit-for-tat cooperative exchanges (similar to Trust First at Wikia.com). His program which played with this strategy dominated Axelrod's competitions to discover the best cooperative strategies using the prisoner's dilemma and software agents.