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Tit for tat

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  Tit for tat Seymore4Head <Seymore4Head@Hotmail.invalid> - 2015-04-26 17:35 -0400
    Re: Tit for tat Ben Finney <ben+python@benfinney.id.au> - 2015-04-27 09:40 +1000
      Re: Tit for tat Seymore4Head <Seymore4Head@Hotmail.invalid> - 2015-04-26 21:40 -0400
        Re: Tit for tat Rustom Mody <rustompmody@gmail.com> - 2015-04-26 18:50 -0700
        Re: Tit for tat Ben Finney <ben+python@benfinney.id.au> - 2015-04-27 12:48 +1000
        Re: Tit for tat John Ladasky <john_ladasky@sbcglobal.net> - 2015-04-26 22:50 -0700
          Re: Tit for tat John Ladasky <john_ladasky@sbcglobal.net> - 2015-04-26 22:58 -0700
          Re: Tit for tat Seymore4Head <Seymore4Head@Hotmail.invalid> - 2015-04-27 23:18 -0400
            Re: Tit for tat Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-28 16:58 +1000
              Re: Tit for tat Robert Kern <robert.kern@gmail.com> - 2015-04-28 21:09 +0100
                Re: Tit for tat John Ladasky <john_ladasky@sbcglobal.net> - 2015-04-28 15:16 -0700
                  Re: Tit for tat Seymore4Head <Seymore4Head@Hotmail.invalid> - 2015-04-28 20:03 -0400
                  Re: Tit for tat Rustom Mody <rustompmody@gmail.com> - 2015-04-28 18:33 -0700

#89432 — Tit for tat

https://www.youtube.com/watch?v=48EWLj3gIJ8

Anyone here worked on trying a better strategy?

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#89434

Seymore4Head <Seymore4Head@Hotmail.invalid> writes:

> Anyone here worked on trying a better strategy?

If you want us to spend the time visiting a link, please spend the time
yourself to summarise why it's relevant here. Do so in the initial post
with the link.

-- 
 \     “Some mornings, it's just not worth chewing through the leather |
  `\                                             straps.” —Emo Philips |
_o__)                                                                  |
Ben Finney

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#89435

On Mon, 27 Apr 2015 09:40:04 +1000, Ben Finney
<ben+python@benfinney.id.au> wrote:

>Seymore4Head <Seymore4Head@Hotmail.invalid> writes:
>
>> Anyone here worked on trying a better strategy?
>
>If you want us to spend the time visiting a link, please spend the time
>yourself to summarise why it's relevant here. Do so in the initial post
>with the link.

Richard Dawkins explains with passion the idea of game theory and tit
for tat, or why cooperation with strangers is often a strong strategy.

He talks of a computer program tournament.  I don't know what I could
say that would be more interesting than just watching the video.

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#89436

On Monday, April 27, 2015 at 7:11:08 AM UTC+5:30, Seymore4Head wrote:
> On Mon, 27 Apr 2015 09:40:04 +1000, Ben Finney wrote:
> 
> >Seymore4Head  writes:
> >
> >> Anyone here worked on trying a better strategy?
> >
> >If you want us to spend the time visiting a link, please spend the time
> >yourself to summarise why it's relevant here. Do so in the initial post
> >with the link.
> 
> Richard Dawkins explains with passion the idea of game theory and tit
> for tat, or why cooperation with strangers is often a strong strategy.
> 
> He talks of a computer program tournament.  I don't know what I could
> say that would be more interesting than just watching the video.

That's a good summary.
Many people would not click on any-ol video

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#89437

Seymore4Head <Seymore4Head@Hotmail.invalid> writes:

> Richard Dawkins explains with passion the idea of game theory and tit
> for tat, or why cooperation with strangers is often a strong strategy.
>
> He talks of a computer program tournament.

Thanks! That is what would be great to have when you present the link in
the first message. That way we know *why* we should go visit an
otherwise context-free link.

-- 
 \           “The basic fact about human existence is not that it is a |
  `\                tragedy, but that it is a bore.” —Henry L. Mencken |
_o__)                                                                  |
Ben Finney

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#89445

On Sunday, April 26, 2015 at 6:41:08 PM UTC-7, Seymore4Head wrote:
 
> Richard Dawkins explains with passion the idea of game theory and tit
> for tat, or why cooperation with strangers is often a strong strategy.
> 
> He talks of a computer program tournament.  I don't know what I could
> say that would be more interesting than just watching the video.

Well, I'm not sure sure what any of this has to do with Python -- but since I know something about the subject, I'll reply.

That Richard Dawkins video is quite old -- it would appear to be from the middle 1980's.  Douglas Hofstadter's 1985 book, _Metamagical_Themas_, covered this exact same material.  A game called the "Iterated Prisoner's Dilemma" is played (I'll abbreviate it as IPD).  Humans can play, of course, but in this case it is played by algorithms.  An algorithm called "Tit for Tat" is surprisingly simple and robust.  When meeting a new contestant, Tit for Tat plays nice in round 1; and on every subsequent round, it plays however that opponent played the last time.  

Evolutionary biologists like Dawkins point to the success of Tit for Tat in IPD as a model of how cooperation could emerge in a population of selfish organisms.  Now, in a round-robin IPD game, Tit for Tat wins pretty handily.  But in some other scenarios, as I recall, Tit for Tat is not a runaway winner.

Suppose that instead of each strategy playing EVERY other, each strategy inhabits a "territory" in a space, and each strategy only plays its neighbors.  In "rough neighborhoods", Tit for Tat can lose out to more punitive strategies.  If Tit for Tat is around more cooperative strategies, it thrives.  The boundaries between good neighborhoods and bad are chaotic.  Tit for Tat more or less holds the borders, but usually can't clean out a bad neighborhood.

This finding came out many years after the Hofstadter and Dawkins reports, so it's not covered in the video.  My reference to the idea is a 1997 paper entitled "The Undecidability of the Spatialized Prisoner's Dilemma," by Patrick Grim (http://link.springer.com/article/10.1023%2FA%3A1004959623042).

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#89446

Following up to myself...

Here's a link to Patrick Grim's results that you can actually download (Springer really retains a 1997 research paper behind a paywall?):

http://www.pgrim.org/pgrim/SPATIALP.HTM

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#89475

On Sun, 26 Apr 2015 22:50:03 -0700 (PDT), John Ladasky
<john_ladasky@sbcglobal.net> wrote:

>On Sunday, April 26, 2015 at 6:41:08 PM UTC-7, Seymore4Head wrote:
> 
>> Richard Dawkins explains with passion the idea of game theory and tit
>> for tat, or why cooperation with strangers is often a strong strategy.
>> 
>> He talks of a computer program tournament.  I don't know what I could
>> say that would be more interesting than just watching the video.
>
>Well, I'm not sure sure what any of this has to do with Python -- but since I know something about the subject, I'll reply.
>
>That Richard Dawkins video is quite old -- it would appear to be from the middle 1980's.  Douglas Hofstadter's 1985 book, _Metamagical_Themas_, covered this exact same material.  A game called the "Iterated Prisoner's Dilemma" is played (I'll abbreviate it as IPD).  Humans can play, of course, but in this case it is played by algorithms.  An algorithm called "Tit for Tat" is surprisingly simple and robust.  When meeting a new contestant, Tit for Tat plays nice in round 1; and on every subsequent round, it plays however that opponent played the last time.  
>
>Evolutionary biologists like Dawkins point to the success of Tit for Tat in IPD as a model of how cooperation could emerge in a population of selfish organisms.  Now, in a round-robin IPD game, Tit for Tat wins pretty handily.  But in some other scenarios, as I recall, Tit for Tat is not a runaway winner.
>
>Suppose that instead of each strategy playing EVERY other, each strategy inhabits a "territory" in a space, and each strategy only plays its neighbors.  In "rough neighborhoods", Tit for Tat can lose out to more punitive strategies.  If Tit for Tat is around more cooperative strategies, it thrives.  The boundaries between good neighborhoods and bad are chaotic.  Tit for Tat more or less holds the borders, but usually can't clean out a bad neighborhood.
>
>This finding came out many years after the Hofstadter and Dawkins reports, so it's not covered in the video.  My reference to the idea is a 1997 paper entitled "The Undecidability of the Spatialized Prisoner's Dilemma," by Patrick Grim (http://link.springer.com/article/10.1023%2FA%3A1004959623042).

In the past, I have had some measure of success with the Toot for Tail
strategy.

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#89482

On Tuesday 28 April 2015 13:18, Seymore4Head wrote:

> In the past, I have had some measure of success with the Toot for Tail
> strategy.


I don't believe that is a standard name for an Iterated Prisoner's Dilemma 
strategy. I've googled for it, using two different search engines, and 
neither come up with any references for "Toot For Tail" strategies.



-- 
Steve

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#89503

On 2015-04-28 07:58, Steven D'Aprano wrote:
> On Tuesday 28 April 2015 13:18, Seymore4Head wrote:
>
>> In the past, I have had some measure of success with the Toot for Tail
>> strategy.
>
> I don't believe that is a standard name for an Iterated Prisoner's Dilemma
> strategy. I've googled for it, using two different search engines, and
> neither come up with any references for "Toot For Tail" strategies.

I do believe he is trying to make a crude joke.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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#89504

On Tuesday, April 28, 2015 at 1:10:14 PM UTC-7, Robert Kern wrote:
> On 2015-04-28 07:58, Steven D'Aprano wrote:

> I do believe he is trying to make a crude joke.

I agree, that's what he's doing.  And I find it ironic, since he started this thread, and seemed to invite a serious discussion of the topic.

I thought that Patrick Grim's analysis was very interesting, showing that the Spatialized Iterated Prisoner's Dilemma (SIPD) could emulate the Wireworld cellular automaton, which is a Turing-complete system.  Thus, the SIPD, a seemingly simple system at first glance, includes configurations which are formally undecidable in the Gödelian sense.  I'm not sure whether Grim proved that an SIPD which includes the Tit for Tat strategy could emulate Wireworld, but it seems likely that one could be built.

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#89506

On Tue, 28 Apr 2015 15:16:05 -0700 (PDT), John Ladasky
<john_ladasky@sbcglobal.net> wrote:

>On Tuesday, April 28, 2015 at 1:10:14 PM UTC-7, Robert Kern wrote:
>> On 2015-04-28 07:58, Steven D'Aprano wrote:
>
>> I do believe he is trying to make a crude joke.
>
>I agree, that's what he's doing.  And I find it ironic, since he started this thread, and seemed to invite a serious discussion of the topic.
>
I did start out serious.  I thought I was making a pretty funny joke
too.  I though both were allowed.
I guess not.  Sorry

What I was fishing for were personal stories of programmers that had
tried the tit for tat program challenge.

>I thought that Patrick Grim's analysis was very interesting, showing that the Spatialized Iterated Prisoner's Dilemma (SIPD) could emulate the Wireworld cellular automaton, which is a Turing-complete system.  Thus, the SIPD, a seemingly simple system at first glance, includes configurations which are formally undecidable in the Gödelian sense.  I'm not sure whether Grim proved that an SIPD which includes the Tit for Tat strategy could emulate Wireworld, but it seems likely that one could be built.

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#89507

On Wednesday, April 29, 2015 at 3:46:24 AM UTC+5:30, John Ladasky wrote:

> I thought that Patrick Grim's analysis was very interesting, showing that the 
> Spatialized Iterated Prisoner's Dilemma (SIPD) could emulate the Wireworld 
> cellular automaton, which is a Turing-complete system.  Thus, the SIPD, a 
> seemingly simple system at first glance, includes configurations which are 
> formally undecidable in the Gödelian sense.  I'm not sure whether Grim proved 
> that an SIPD which includes the Tit for Tat strategy could emulate Wireworld, 
> but it seems likely that one could be built.

Thanks John for those pointers -- Ive been looking at it with interest.
This area is of some interest to me -- as my last two blog posts would indicate
http://blog.languager.org/2015/04/poverty-universality-structure-0.html
http://blog.languager.org/2015/03/cs-history-0.html

------------------------
PS Google groups invites to writing longlines which causes trouble to some
people out here (with historical machines?).

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