[extropy-chat] Appeasement

Eugen Leitl eugen at leitl.org
Mon Apr 11 13:50:24 UTC 2005

On Sun, Apr 10, 2005 at 08:57:51PM -0700, The Avantguardian wrote:

> Hmmm well in response to your criticism, I did a
> search and gound an interesting site:
> http://www.prisoners-dilemma.com/results/cec04/ipd_cec04_full_run.html
> This site lists tournament results of repeated games
> of prisoner's-dillemna. Apparently my info was a
> little out for date as FTFT only placed 39 in the last
> tournament (still better than normal TFT) but it
> indicates that there are better strategies out there
> then either. I myself am somewhat curious about the
> details of those strategies. :)

You've seen http://wired-vig.wired.com/news/culture/0,1284,65317,00.html


Teams could submit multiple strategies, or players, and the Southampton team
submitted 60 programs. These, Jennings explained, were all slight variations
on a theme and were designed to execute a known series of five to 10 moves by
which they could recognize each other. Once two Southampton players
recognized each other, they were designed to immediately assume "master and
slave" roles -- one would sacrifice itself so the other could win repeatedly.

If the program recognized that another player was not a Southampton entry, it
would immediately defect to act as a spoiler for the non-Southampton player.
The result is that Southampton had the top three performers -- but also a
load of utter failures at the bottom of the table who sacrificed themselves
for the good of the team.

Another twist to the game was the addition of noise, which allowed some moves
to be deliberately misrepresented. In the original game, the two prisoners
could not communicate. But Southampton's design lets the prisoners do the
equivalent of signaling to each other their intentions by tapping in Morse
code on the prison wall.

Kendall noted that there was nothing in the competition rules to preclude
such a strategy, though he admitted that the ability to submit multiple
players means it's difficult to tell whether this strategy would really beat
Tit for Tat in the original version. But he believes it would be impossible
to prevent collusion between entrants.


Eugen* Leitl <a href="http://leitl.org">leitl</a>
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