MARJORIE CHASOWA (092SIS08)
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Simultaneous actions done through ignoring
the other’s choice
No time to make/change decisions in
response to the discovery of the others’
Be in both shoes (contender & self) and take
the best move for both sides
e.g. Herald & Daily News (eye-catching stories
competition behind closed doors)
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Player has an single way that makes one
above the contender no matter their
response
No need to worry about the contender’s
moves
E.g Indiana Jones & the Last Crusade
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E.g Herald & Daily News (Sanctions & AIDS
cases)
Herald needs to take the sanctions story
because it is the dominant
30
65
S
Herald’s
strategy
25
15
choices
A
S
A
Daily News’
choices
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Dominant strategy is one that makes you
better off than you would be if you used any
other strategy, no matter what strategy your
opponent uses
If you have a dominant strategy, use it
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Eliminate any dominated strategies from
consideration & proceed successively
blitz
E.g. American football game
Offense’s
strategy
Offense is strong at
passing & weak at running
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run
2
4
10
pass
5
8
9
counter
pass
Counter
run
Defense’s
strategy
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Neither side has dominant strategy as shown
by no row with numbers uniformly
smaller/larger than those in the other row
Defense had a dominated strategy i.e. blitz
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Team defensive maneuver in which one/more
defensive backs are instead sent across the
line to the offensive side to try to tackle the
quarterback/ disrupt pass attempt
Advantages
 Proactively disrupt the offenses play before it
develops
 Cause enough pressure on the quarterback to
force him into a turnover
Disadvantages
 Offensive linemen are usually trained to
recognise the blitzing player before & thus
can be picked & stopped prematurely
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If blitz is picked up, the one deep defender
will have a bigger territory to guard
Is pass is caught, the receiver can turn a
minimal gain into a dangerous play
Blitz can be defeated with more aggressive
release moves
So? Blitz should be avoided. Offense will
choose to pass & defense best response i.e.
pass defense
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Need for squaring the circle in order to get
out of the circular reasoning
e.g Herald & Daily News
Daily
News’
response
Herald’s Prices
Herald’s
response
Daily News’ Prices
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None wants to change their move due to
need to have more profits and end up at Nash
equilibrium
Thus, having exhausted simple avenues of
looking for dominant strategies/ avoiding
dominated ones, looking for an equilibrium
becomes important
1. Circular reasoning gets to nowhere and
needs to be avoided
 Equilibrium is stable, makes the players
have consistent expectations & chose best
response
2. Zero-sum games, players interests are
opposed strictly & deception is limited
3. Pragmatic , “pudding’s proof is in the eating”
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When an outcome is an equilibrium, it doesn’t
necessarily translate into being the best for
all as it depends with the circumstances
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Feast implies having much equilibria
Games having many equilibria
e.g. driving to the right/left
E.g. Webby/Pearl calls
Need for common understanding of which
equilibrium to pick to reduce confusion
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Implies having no equilibrium
Determinate behaviour should be avoided
through mixing moves
Mixing strategy pivotal in cooperation
E.g. Webby/Pearl calls (50% chances)
3 rules of action in simultaneous moves games
1. Look & use dominated strategies
2. Look for & avoid dominated strategies
3. Look for & use an equilibrium
Dominant
strategies
Dominated
strategies
Equilibrium
strategies
1.
How can notions of rationality/ irrationality
be explained vs notions of being
humane/ethical be explained in the Indiana
Jones case?
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THANK YOU
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TATENDA