1. 博弈真人 实验 介 绍 Xiongrui Xu Compleχ Lab 4/4/2015

2. Haixing Dai Compleχ Lab, University of Electronic Science and Technology of China, Chengdu 611731, P.R.C.

3. Results of our game

4. Prisoner’s Dilemma 李四的选择 合作 （抗拒 警察） 背叛 （坦白 罪行） 张三 的选择 合作 （抗拒 警察） -1,-1-5, 0 背叛 （坦白 罪行） 0,-5-3,-3 Y’s choce CD X’s choice CR, RS, T D T, SP, P C: Cooperation D: Defection R: Reward S: Suck T: Tempation P: Punishment T > R>P>S 2R > T+S

5. Zero-Determinant Strategies Extortion strategies Generosity strategies C Hilbe, T Röhl, M Milinski - Nature communications(2014); Extortion subdues human players but is finally punished in the prisoner's dilemma

6. 2x2 Game Model Two-playerTwo strategies Cooperation(C) Defection(D)

7. Models and Methods ZD Strategy (Computer Program) Number of human co-player Strongly Extortionate(ES) 16 Mildly Extortionate(EM) 14 Mildly Generous(GS) 14 Strongly Generous(GM) 16 60 rounds C Hilbe, T Röhl, M Milinski - Nature communications(2014); Extortion subdues human players but is finally punished in the prisoner's dilemma

8. Results C Hilbe, T Röhl, M Milinski - Nature communications(2014); Extortion subdues human players but is finally punished in the prisoner's dilemma

9. Results  Assumption:  The feeling of unfair  Withholding cooperation as a form of costly punishment. C Hilbe, T Röhl, M Milinski - Nature communications(2014); Extortion subdues human players but is finally punished in the prisoner's dilemma

10. Conclusions  Generosity strategy is more effective to promote cooperation than extortion strategy, while the latter ‘win each battle, but at the expense of losing the war’.  It may be the feeling of unfair leads to the low cooperation rate in extortion treatments, which demonstrates that monetary incentive alone are not enough to maintain cooperation in long-term relationship. C Hilbe, T Röhl, M Milinski - Nature communications(2014); Extortion subdues human players but is finally punished in the prisoner's dilemma

11. Thanks Xiongrui Xu Compleχ Lab 4/4/2015