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*> From: Chan Dorothy <dwyc195@psy.soton.ac.uk>
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*>
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*> I am reading the commentary for Mealey's article and I don't quite get
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*> the "game of Chicken" by Maynard Smith(which appears in Andre M.
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*> Colman's comm.). The model talks about a mixed-strategy equlibrium
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*> point which the population will evolve into. What is this point
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*> got to do with the probability of choosing to cooperate or to
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*> defect? Is this model different from the Prisoner's Dillema because
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*> it takes into account the no. of people who chosse either to
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*> cooperate or to defect tend to fluctuate? How does this model
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*> determine what is the payoff for choosing to cooperate (or to
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*> defect?)
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The table was garbled and the figure was missing. I've fixed the table

and put a verbal description of the figure into the commentary. (Of

course the published version in the resource room is correct; the error

was only in the email version.)

In both Classical Prisoner's Dilemma and the "Chicken" variant, the

game can be one-time or iterated (repeated many times); it can also be

one against one, or collective, testing what happens if one person

defects and everyone else cooperates, and so on. For the classical

Prisoner's Dilemma, the payoffs are, in decreasing order T(emptation)

(I defect, everyone else cooperates) R(eward) (I cooperate and everyone

else does too) P(unishment) (I defect, and everyone else does too)

S(ucker's punishment) (I cooperate and everyone else defects).

In the "Chicken" variant, the order, instead of T R P S is T R S P.

That means I do worse if everyone defects than if I cooperate and

everyone else defects.

In the classical TRPS version of the game, defecting is always the

stable strategy for everyone. In the "chicken" TRSP version, depending on

how many defectors there are, up to a certain proportion, cooperating

is better; beyond that point, defecting is better. So the stable

strategy converges on a mixture of both types (and exactly what

proportion of each there will be depends on the actual cost/reward

numbers you give to T, R, etc.).

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