We investigate an infinitely repeated prisoners' dilemma with imperfect monitoring and projects the possibility that the interlinkage of the players' distinct activities enhances implicit collusion. We show a necessary and sufficient condition for the existence of generous tit-for-tat Nash...

We examine repeated prisoners' dilemma with imperfect private monitoring and random termination where the termination probability is low. We run laboratory experiments and show subjects retaliate more severely when monitoring is more accurate. This experimental result contradicts the prediction...