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TITFORTAT

          
                                         Additions:  July 7, 2000

Robert Axelrod's "The Evolution of Cooperation":

      I think Axelrod essentially    
      confirms that much of what     
      we normally think of as              He makes the point that 
      "altruistic" behavior can            cooperative behavior can 
      arise from purely "selfish"          and does evolve in 
      behavior.                            adversarial situations, 
                                           even without any direct 
           The way I'd put it:             communication to assist
           What is usually thought of      the process (e.g. WWI 
           as "selfishness" is really      trench warfare, where 
           "shortsightedness".             each side of a stand-off
                                           would gradually learn 
                                           to avoid any real attempt 
                                           at attacking each other.)
                                           
       The moral may                       Much is made of  
       be grounded in the                  a computerized 
       real.                               tournament, an 
                                           indefinite series 
           The idealistic,                 of prisoner's 
           derivable from                  dilemma games, 
           the pragmatic.                  where the winning 
                                           strategy was 
                        A is A?            nearly always  
                                           the exceedingly 
                         And               simple "Tit for Tat". 
                         D is D.                                
                                                      Tit for Tat: 
                                                      Always cooperate, 
                                                      unless your 
                                                      opposite number 
                                                      defected on the 
                                                      immediately 
                                                      previous move. 
                                                                         
                                                         Be helpful.     
                                                         Retaliate immediately
                                                            when wronged. 
                                                         Forgive quickly.
                                                                         
                  COMPLAIN_COMPLAIN_COMPLAIN            
                                                         This certainly 
                                                         isn't my strategy:
                                                         I'm inclined to 
A subject: the difficulty of                             the "slow to anger, 
applying the idea of                                     but never forget"
"Tit for Tat".                                           style.  
                                                                 
e.g. what's an appropriate                                       
tat for a given tit?                                     I think it's notable 
                                                         that a close         
Should you apply a                                       competitor of        
sliding scale of                                         Tit-for-Tat          
reprisals, where                                         was Tit-for-Two-Tats, 
you hit back harder     But... attempts                  i.e. let the first   
after a repeated        at more complicated              one slide, and       
offense?                strategies with                  retaliate on the     
                        memory were failures             second offence.       
How do you manage to    in the tournament.               
be both "provocable"                                     A variation of  
and "forgiving" in a                                     "turn the other 
world where things                                       cheek"... given 
are not neatly                                           that we only      
divided into rounds                                      have two cheeks.   
of exchanges of a                                                           
limited kind of                                                (or is it   
interaction?                                                   four?)        
                                                                            
And... isn't Tit for Tat                                                  
a strategy that can                                                          
reduce you to the level                                                  
of your opponent?                                                        
                                                                            
You can lose when trying to                                                    
convince a third party that                                                 
you're not as bad as your                                                   
opponent.  Yelling "He                                                  
started it!"  isn't going to                        The question is,       
distinguish you very well                           is it possible that
when both sides are lying,                          the tournament     
cheating and killing.                               results are not    
                                                    strictly applicable 
                                                    to reality, which is 
                                                    not precisely a simple 
                                                    extended series of 
                                                    Prisoner's Dilemma 
                                                    games.
                                                    
                                                    Maybe Tit-for-two-tats
                                                    would win in a tournament 
                                                    with parameters closer 
                                                    to reality? 
                                                                
                                                          What happens if 
                                                          you have some 
                                                          freedom to choose 
                                                          who you're going 
                                                          to play with 
                                                          next?  
                                                          
                                                          As I remember it 
                                                          Axelrod's tournament 
                                                          involved only 
                                                          random pairing of 
                                                          players. 
                                                                   
                                                                Preserving 
                                                                reputation 
                                                                could be 
                                                                worth the 
                                                                loss of  
                                                                a round. 

                                     

                                     March 7, 2003

Axlerod shows that some of what we consider civilized
behavior ("cooperation") falls out of the mathematics
of strategy.  The original nature of the autonomous
agents may not matter very much... if they *are*
autonomous, you can expect that they'll tend to
converge on a certain kind of behavior over time.

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