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The easiest way into this piece is through its title, cut from the opening
lines of T.S. Eliot’s “The Waste Land:”
April is the cruellest month, breeding
Lilacs out of the dead land, mixing
Memory and desire, strirring
Dull roots with spring rain.
I have lifted the line as Eliot has written it and isolated
it, leaving it hanging. The “stirring” seemingly refers to
“memory and desire,” perhaps as Eliot intended. This type
of editing is a common strategy is in my work, as well as in Eliot’s
epic poem.
There are 4 points the viewer of “Memory and
desire, stirring” may want to know:
- This work posits two clips against each other in a battle for screen
position. Of these two clips, one is memory, the other is desire.
- The clips battle by running the Prisoner’s
Dilemma algorithm over and over.
- The winning images build a composition over 3 rounds of play.
- The winning composition stays on screen for about 10 seconds, then
is gone forever.
The Prisoner's Dilemma
The Prisoner's Dilemma was conceived of in the 1950's as part of
research involving game theory and Cold War military simulations. It is
a way of modeling behavior in individuals in group dynamics. It's a way
of thinking about "confessing" or "keeping silent"
when one's decision effects someone else.
Two suspects, A and B, are arrested by the police.
The police have insufficient evidence for a conviction, and, having
separated both prisoners, visit each of them to offer the same deal:
if one testifies for the prosecution against the other and the other
remains silent, the betrayer goes free and the silent accomplice receives
the full 10-year sentence. If both stay silent, both prisoners are
sentenced to only six months in jail for a minor charge. If each betrays
the other, each receives a two-year sentence. Each prisoner must make
the choice of whether to betray the other or to remain silent. However,
neither prisoner knows for sure what choice the other prisoner will
make. So this dilemma poses the question: How should the prisoners
act?(w)
But it changes when you run it over and over again. If
the players are given even a little bit of memory and are allowed to know
the other player's previous decisions, then a strategy can be developed.
Interestingly, a strategy that involves forgiveness works to the player's
advantage. I have chosen to give the forgiveness advantage to memory.
I feel desire is unforgiving.
In his book The Evolution of Cooperation (1984), Robert
Axelrod explored an extension to the classical PD scenario, which
he called the iterated prisoner's dilemma (IPD). In this, participants
have to choose their mutual strategy again and again, and have memory
of their previous encounters. Axelrod discovered that when these encounters
were repeated over a long period of time with many players, each with
different strategies, "greedy" strategies tended to do very
poorly in the long run while more "altruistic" strategies
did better, as judged purely by self-interest. He used this to show
a possible mechanism for the evolution of altruistic behaviour from
mechanisms that are initially purely selfish, by natural selection.
The best deterministic strategy was found to be "Tit
for Tat", which Anatol Rapoport developed and entered into the
tournament. It was the simplest of any program entered, containing
only four lines of BASIC, and won the contest. The strategy is simply
to cooperate on the first iteration of the game; after that, the player
does what his opponent did on the previous move. A slightly better
strategy is "Tit for Tat with forgiveness". When the opponent
defects, on the next move, the player sometimes cooperates anyway,
with a small probability (around 1%-5%). This allows for occasional
recovery from getting trapped in a cycle of defections. The exact
probability depends on the line-up of opponents. "Tit
for Tat with forgiveness" is best when miscommunication
is introduced to the game — when one's move is incorrectly reported
to the opponent.(w)
Consider this regarding Rapoport's winning algorithm:
According to Peace Magazine author/editor Metta Spencer,
the program "punished the other player for selfish behaviour
and rewarded her for cooperative behaviour -- but the punishment lasted
only as long as the selfish behaviour lasted. This proved to be an
exceptionally effective sanction, quickly showing the other side the
advantages of cooperating. It also set moral philosophers to proposing
this as a workable principle to use in real life interactions. (w)
In this work the Prisoner's Dilemma is encoded with the
Tit for Tat with forgiveness strategy in ActionScript, . The
Desire clip always picks first, randomly, 1 or 0. The Memory clip always
choose Desire's previous choice. If that choice was 0, or false, there
is a 5% chance of forgiveness; Memory will not copy Desire in betrayal,
but instead change to 1, meaning it will co-operate. This gives Memory
the advantage over Desire. Memory forgives Desire. This is one of the
conclusions arrived at via this artwork.
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