EXTENSION ON THE EVOLUTION OF COOPERATION

MPhil Thesis Defence


Title: "EXTENSION ON THE EVOLUTION OF COOPERATION"

By

Miss Zhuoya XIANG


Abstract

The evolution of cooperation (or cooperation theory) is the study of how 
cooperation can emerge and persist, and its modern developments are put forth 
by a political scientist Axelrod. His work is based on the model of Iterated 
Prisoner’s Dilemma (IPD), where two prisoners have the options to cooperate or 
defect when defection yields higher payoff than cooperation whatever the other 
does. Several propositions about the game and collective stabilities of various 
strategies provide realistic guidance for how to react in such situations and 
illuminate certain aspects of evolutionary biology, moral and political 
philosophy.

In this thesis, we design a few more game models that cover a wider range of 
situations in the real world, such as IPD with more than two options and 
continuous IPD games. We conduct several computer tournaments on the 
generalized models to analyze how to react accordingly. The results from the 
experiment show that the winner of Axelrod’s tournaments, TFT, still leads a 
strong position in the games, but has an obvious drawback in the continuous 
model. Meanwhile, a new class of strategies, namely STEPPER, have absolute 
advantage, and a subclass of it is proved to be collectively stable. Given the 
non-cooperative nature of STEPPER, we conclude that cooperation can hardly 
emerge in the continuous model. Hence, suggestions for the players is that try 
to exploit others at the least possible expense, however, if it fails, restore 
mutual cooperation as soon as possible.


Date:			Thursday, 25 June 2015

Time:			10:00am – 12:00noon

Venue:			Room 2132C
 			Lift 19

Committee Members:	Prof. Fangzhen Lin (Supervisor)
 			Dr. Ke Yi (Chairperson)
 			Dr. Qiong Luo


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