博弈真人实验介绍
Xiongrui Xu
Compleχ Lab
4/4/2015
Haixing Dai
Compleχ Lab,
University of Electronic Science and Technology
of China,
Chengdu 611731, P.R.C.
Results of our game
Prisoner’s Dilemma
李四的选择
合作
背叛
（抗拒
（坦白
警察）
罪行）
T > R>P>S
2R > T+S
张三
的选择
C
合作
（抗拒 Y’s choce
-1,-1
警察）
背叛 C
（坦白
罪行）
R, R
T, S
D: Defection
D
0,-5
-3,-3
R: Reward
S, T S: Suck
X’s choice
D
-5,C: 0Cooperation
P, P
T: Tempation
P: Punishment
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
2x2 Game Model
Two-player
Two strategies
Cooperation(C)
Defection(D)
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
Results
C Hilbe, T Röhl, M Milinski - Nature communications(2014);
Extortion subdues human players but is finally punished in the prisoner's dilemma
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
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
Thanks
Xiongrui Xu
Compleχ Lab
4/4/2015