Games as Cybernetic Systems
systems theory + information theory
thinking about feedback
Cybernetics - wikipedia
 Cybernetics is a theory of the
communication and control of regulatory
feedback.
 The term cybernetics stems from the Greek
Κυβερνήτης (meaning steersman, governor,
pilot, or rudder).
 Cybernetics is the discipline that studies
communication and control in living beings
and in the machines built by humans.
COSC 4126 cybernetics
Homeostasis
Homeostasis is the property of an open system
to regulate its internal environment to maintain
a stable condition, not rigidly fixed but
maintained within a bounded acceptable range.
e.g., eating, drinking, breathing enough to sustain
life
- simulated in characters in many games
- Sim games are based on homeostatic models
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Feedback loop
 an activator produces an effect
 feedback allows the effect to
influence future action
acts to produce effect/result
activator
external
effect
result
activates or not
goal
comparator
sensor
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Feedback for homeostatis
cold
 Negative feedback: how a system
reacts to maintain stable condition outside
generate heat
furnace
temperature
of room
activates or not
thermostat
thermometer
temperature
setting
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Temperature control
furnace
operating
goal
temperature
actual
temperature
time
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Negative feedback - stability
 The term cybernetics stems from the
Greek Κυβερνήτης (meaning
steersman, governor, pilot, or
rudder).
 maintains course close to desired
direction
 other examples
 funnel, sloped wings of aircraft
 predator / prey ecologies
 driving a car
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Automation and high level control
higher level (containing system)
set goal
activator
acts to produce effect/result
result
activates or not
goal
comparator
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sensor
Automated control by goal setting
 e.g., thermostat plus air-conditioner
and furnace
 high level control – set goal temperature
 thermostat activates furnace and airconditioner as required to keep
temperature in range
 reacts to external heat and cold
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Negative and positive feedback
 negative feedback modulates an action
 positive feedback catalyzes an action
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LeBlanc,1999:
 Negative feedback basketball
 for every N points of difference in the
score, the losing team can put another
player on the court
 Positive feedback basketball
 for every N points of difference in the
score, the winning teams can put
another player on the court
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Positive feedback
 amplifies effect of action
 threatens a homeostatic system
opposite condition
produces positive
feedback
activator
acts to produce effect/result
result
activates or not
goal
comparator
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sensor
Positive feedback
 e.g., climate change in Arctic
 atmospheric warming melts ice
 bare soil, open water do not reflect as
much radiation
 warming accelerates
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Feedback and control in
homeostatic systems
breakdown stress equilibrium stress breakdown
range
hypothermia shivering normal sweating hyperthermia
example: body temperature
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Cybernetics in games
 many feedback loops are embedded
in games
 comparators decide action
 in some loops, the comparator is the
player
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“Core mechanic”
the basic action cycles of a game
 exclude peripheral actions like set-up
 focus on core activity of game
 can often be analyzed as feedback loops
with player as ‘comparator’
game
dynamics
input
acts to produce effect/result
state
change
activates or not
goal
display
output
player
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“Core mechanic”
 purpose
 low level skill to be mastered and
automatic as quickly as possible
 tool for higher level play – Sims
 “inefficient” activity in the magic circle?
 learning it is key to fun and meaning
 typically real-time
 e.g., driving game
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Analysis of the feedback loop
1. game dynamics
a) state evolves independent of player
game
dynamics
b) game reacts to player
c) only player causes state change
input
acts to produce effect/result
state
change
activates or not
goal
display
output
player
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Analysis of the feedback loop
2. timing of feedback loop - delay
player sees display of state change of
input
game
dynamics
n before deciding action n+k
input
acts to produce effect/result
state
change
activates or not
goal
display
output
player
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Analysis of the feedback loop
3. input is discrete, “continuous”
player explicitly generates each input;
game
dynamics
how difficult is the input action?
input
acts to produce effect/result
state
change
activates or not
goal
display
output
player
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Analysis of the feedback loop
4. effect of input
state change is deterministic, risky or
game
dynamics
uncertain?
input
acts to produce effect/result
state
change
activates or not
goal
display
output
player
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Analysis of the feedback loop
5. discernability
display shows all effect on state of
game
dynamics
player input?
input
acts to produce effect/result
state
change
activates or not
goal
display
output
player
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Analysis of the feedback loop
6. comparator decision complexity
high level control: is goal fixed or
changing?
how many input alternatives?
input
acts to produce effect/result
game
dynamics
state
change
activates or not
goal
display
output
player
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Summary of feedback loop factors
1.
2.
3.
4.
5.
6.
game dynamics
timing of feedback loop – delay
input is discrete, “continuous”
effect of input
discernability
comparator decision complexity
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Example: driving a vehicle
homeostatic system
crash
left
veer or controlled veer or
travel
skid
skid
right
left
focus on
control
focus on
goal
crash
right
focus on
control
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Example: driving a vehicle
feedback loop
1
2
4
3
6
5
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Designing the core mechanic
feedback loop
1
1. game dynamics
2. timing of feedback loop – delay
3. input is discrete, “continuous”
3
2
4
4. effect of input
5. discernability
6. comparator decision complexity
Two ‘tool’ examples
1. SnagIt
2. Office Draw
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6
5
Feedback at higher levels
Adjusting level to match player skill
 Negative feedback
 adjust AI player skills – e.g., racing games
 adjust random probabilities
 “Dynamic Difficulty Adjustment”
–Naughty Dog Entertainment
 dilemma of the magic circle – is
adjustment fair?
 shown to be counterproductive in
educational software
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Feedback at higher levels
Increase action and variety
 Positive feedback
 introduces instability – e.g., oscillation
 Monopoly cash flow
 reinforces differences
 playoff scheduling
 tennis seeding
 homeostatis – produces new equilibrium
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