The Simplified Strategy of Co-Operating

The simplest strategy is called tit for tat. It co operates on the first move and then does whatever the other guy did on the previous move. A seeming weakness of titfor tat is that it's ver reactive, never probes the other player to see whether he or she is a push over by instigating a non co operative action. If you defect once, i'll ive, but i won't keep forgiving no matter what you do,. So i forgive you as long as you're nice to me.