Information 2

Robin Burke

GAM 224

Spring 2004

Outline

Admin Systems of information Cybernetics

Feedback loops

Admin

Assassinnew rules (see defrag.depaul.edu)deadline to join: Fridaygame starts: Monday

"Rules" paperdue: 10/10 = 12 daysstart to identify thesis / analytic angle

Information

Information theory says that information is a quantitymeasured in bitsbased on the ambiguity of the

situation Says nothing about how messages

are generated or interpreted

Interpretation

Irrelevant to information theory Crucial if we want to understand information in games Example

Game behaviors are more meaningful if• the player can discern success and failure• the behavior has a direct connection to the overall

outcome The game must communicate to the player

• "you did it wrong"• "you're close to winning"

Game must lead player to a correct interpretation

Semiotics 1

Meaning is encoded in signsverbal, gestural, sartorial, etc.

Examplearchitectural configurationthe necktiea yellow ribbon

Semiotics 2

The sign has two parts signifier

• the expression that is made

signified• what the expression represents

The meaning of a signifier is conventional "ya" means "I" in Russian, but "yes" in

German hitchhiker's gesture

Semiotics 3

Decoding a sign is interpretation How the sign is interpreted depends on

the interpreter the context

Games establish a context for signs words, actions, symbols, visual cues the designer creates signifiers for the

important elements of the game the player must learn to extract their

meaning

Semiotics 4

Meaning is created by the interpretation of signifiers in context

A game designer creates a new context with new meanings using particular signifiers

But not in a vacuum signifiers are usually borrowed from the

wider culture the design may rely on aspects of their

conventional meaning

Example: Chess

Signifiers shapes of pieces names for pieces

Cultural Meanings powerful societal roles

In-Game Meanings ability to move ability to control space

Think about the "King"

Example: Almost every FPS

Signifiersred cross

Cultural Meaningsign for hospital

In-Game Meaningan opportunity to recharge "health

meter"

Systems of signs

Signs do not stand alone signs are interpreted in the context of other

signs Consistent semiotic structure

makes your game easier to understand players enjoy decoding clues

• if there is a sensible pattern Example

Mario Bro's Superstar Saga• Enemies that can be attacked with electricity

usually wear or carry something metallic.

From signs to information

The interpretation of signs yields information

Informationabout the state of the gameabout the game environmentabout what just happenedabout what might happen next

Systems of information

Incomplete information makes for interesting gameplaywhy playing cards have a front and

back Types of information

publicprivatehidden

Information economy

Games of information often have an "information economy"a system through which

• hidden information is revealed• private information becomes public

Like all economiesbased on exchange

Example 1

Gin Rummy I don't know what cards my opponent holds If I discard a card and she picks it up

private information is revealed but she is closer to winning

Tradeoff benefit = knowledge of cards held cost = improved opponent position

Example 2

First-person shooter I don't know what opponents are in the next

room or what the layout is

If I walk in I'll learn what the opponents are but I might get killed

Tradeoff benefit = tactical knowledge cost = risk of defeat

Information as reward

Often information is a reward (more about rewards in "Play" unit)

If you are successful in some action the game reveals more information

If you take some extra effort to explore the environment

Could be what to do next

the location of something valuable a map etc.

Example

Information seeking

Players will take action to gain information reduce uncertainty enable preparation / planning

Meaningful choices arise when there are multiple ways to learn when those choices have different costs /

consequences when those choices yield different kinds or

qualities of information

Information revealing

(Especially in multi-player games) Players may need to keep certain

information hiddengain advantage over opponents

Meaningful choices arisewhen exercising an option that might

disclose valuable informationin the possibility of deception

Game Design Issues

What kinds of information are inherent in the design?

What is the status of the information during the game?

How is information communicated? How is hidden information revealed? What are the costs of information? What meaningful choices revolve around

Information Flow

Systems have objects that interactInformation is a quantity that objects in

a system may exchangeWeiner developed cybernetics to

explain this type of system Cybernetics is an attempt to unify the

study of engineered and natural systems

Cybernetic Systems

Cybernetics is about control How is the behavior of a system controlled?

Control implies that there are parameters that should be maintained Example: temperature

• human body• car engine

Control implies information Temperature messages

• "too high"• "too low"• "OK"

Feedback Loops

Basic loop A cybernetic system needs a sensor that

detects its state The information detected by the sensor is

then compared against the desired value If the value is not correct, the system adjusts

its state the sensor detects this new state, etc.

The system maintains stability by feeding the information about its state back

to the process producing the state

Two Types of Feedback Loops Negative Feedback Loop

"inhibition" As the state changes, the loop acts to move it in the

direction of its previous state Example

• thermostat Positive Feedback Loop

"excitation" As the state changes, the loop acts to move it in the

direction that it is moving Example

• automobile turbocharger• home team advantage

Audio example

Feedback Loops in Games

From book

game state scoring function

controllergame mechanical bias

Example

game state state of a fighting game

scoring function player's health

controller near-KO

bias increase chance of critical (high damage) hit

on opponent

Effects?

Example 2

game state state of the chessboard

scoring function the number of pieces taken

controller for each piece taken

bias add a pawn to the taker's side in any position

Effects?

Examples

Multiple Loops

Games may have multiple feedback loops in operation Examples

racing game• a player who falls behind may be better power-ups• AI racers may adjust their ability to keep pace with player

RPG• killing monsters gives experience points for gaining levels• as a player gains levels, they gain better weapons and greater

abilities• more success at killing monsters, etc.• but

• game is designed so advanced areas have tougher monsters• levels get farther and farther apart

In General

Negative feedback loopsincreases system stabilitymakes the game last longermagnifies late successes

Positive feedback loopsdestabilizes the systemmakes the game shortermagnifies early success

The Other Sense

We also use the word "feedback" to mean praise vs criticism "I got some negative feedback on the

proposal, so I'm revising it." This is not the same

psychological sense of feedback• information about the quality of something

• good or bad cybernetic sense of feedback

• a dynamic established by a system's structure that pushes its state in one direction or another

• in response to information

Game Design Issues

Know what feedback is going on in your systemanalyze how game mechanisms

combine to produce feedback Feedback may be undesirable

negative feedback may make a successful player feel punished

positive feedback may magnify ability differences between players

Monday

Quiz #1: Rules Game design exercise