关键词: 囚徒困境 重复囚徒困境 博弈论 学习和响应

Abstract:

Being an important example in game theory, Prisoner＇s Dilemma （PD） has attracted widespread attention in a variety of disciplines such as economics
          , sociology and biology. Iterated Prisoner＇s Dilemma （IPD）was studied by Robert Axelrod in[1]to model the evolution of cooperation. In the game of IP  PD, two players repeatedly play PD and have the memory of the previous encounters. In the computer IPD tournaments organized by Axelrod, a simple strate  gy TFT （Tit for it） won twice. After that, a great mtmber of researchers sought to design new strategies to beat TFT in the tournament, but without mu  uch success. We propose a learning and response model for IPD which has many real-life strategies as its implementations. After analyzing the difficulty and complexity of implementing our model, we give a tree-based strategy and com- pare it with TFT in IPD toumaments~ Experimental results show that a s  trategy＇s behavior largely depends on its way to balance the trade-off between the learning cost and the overall payoff,and depends on how it investigaates and utilizes its opponent＇s characteristics based on what it has learned.

Key words:  （prisoner＇ s dilemma, iterated prisoner＇ s dilemma, game theory, learning and response）