Information / CyberneticsOutlineAdminReaction PapersUncertaintyCertainty vs uncertaintyProbabilitySingle DieTwo diceRole of ChanceRole of Chance 2PsychologyInformation TheoryInformation Theory 2NoiseExampleExample, cont'dInformation FlowCybernetic SystemsFeedback LoopsTwo Types of Feedback LoopsFeedback Loops in GamesExample 1Effects?Example 2Slide 26Example 3Slide 28ExamplesMultiple LoopsIn GeneralThe Other SenseGame Design IssuesExample gamePlayHomework #2Slide 37Homework #2 cont'dMondayInformation /CyberneticsRobin BurkeGAM 224Winter 2007OutlineReaction PapersProbability and Information TheoryCyberneticsFeedback loopsHomework #2Admin1st Reaction paper due MondayReaction PapersGame syllabus Grand Theft Auto 3, Grand Theft Auto: Vice City, Grand Theft Auto: San Andreas, or BullyHalf-Life or Half-Life 2Katamari Damacy or We Love KatamariAge of Mythology, Civilization IV, Lord of the Rings: Battle for Middle Earth (I or II), Total War(any) or WarCraft IIIGuitar Hero, Guitar Hero II, or Dance Dance Revolution (any)Gears of War, Dead Rising, Rainbow Six: Vegas, or Ghost Recon: Advanced Warfighter (XBOX 360)Play one game a weeksubmit a one-page reaction paperDue dates: 1/22, 2/5, 2/14, 2/21, 2/28, 3/7Objectexercise game analysis skillsuse the analytic schemas from the bookUncertaintyMany games are probabilisticroll the diceshuffle the cardsSome games are notChessCheckersDots and BoxesCertainty vs uncertaintyCertaintythe condition when the outcome of an action is known completely in advance.Some games operate this wayChessDots and BoxesBut even thenuncertainty about who will winotherwise what is the point?ProbabilityProbability is the study of chance outcomesoriginated in the study of gamesBasic ideaa random variablea quantity whose value is unknown until it is "sampled"the random variable has a distribution•for each possible value•a probability that the value will occurSingle DieRandom variable# of spots on the side facing upDistribution1...6each value 1/6 of the timeSame event, different random variableodd or even # of dotsTwo diceRandom variablesum of the two die valuesDistribution2, 12 = 1/363, 11 = 1/184, 10, = 1/125, 9 = 1/96, 8 = 5/367 = 1/6Non-uniformnot the same as picking a random # between 2-12dice games use this factRole of ChanceChance can enter into the game in various waysChance generation of resourcesdealing cards for a game of Bridgerolling dice for a turn in BackgammonChance of success of an actionan attack on an RPG opponent may have a probability of succeedingChance degree of successthe attack may do a variable degree of damageRole of Chance 2Chance changes the players' choicesplayer must consider what is likely to happen•rather than knowing what will happenChance allows the designer more latitudethe game can be made harder or easier by adjusting probabilitiesChance preserves outcome uncertainty with reduced strategic inputexample: ThunderstormPsychologyPeople are lousy probabilistic reasonersWe overvalue low probability events of high risk or rewardExample: Otherwise rational people buy lottery ticketsWe assume success is more likely after repeated failureExample: "Gotta keep betting. I'm due."Impacts for game designInformation TheoryThere is a relationship between uncertainty and informationInformation can reduce our uncertaintyExampleThe cards dealt to a player in "Gin Rummy" are private knowledgeBut as players pick up certain discarded cards from the pileIt becomes possible to infer what they are holdingInformation Theory 2Classical Information TheoryShannonInformation as a quantityhow information can a given communication channel convey?•compare radio vs telegraph, for examplemust abstract away from the meaning of the information•only the signifier is communicated•the signified is up to the receiverInformation is measured in bitshow many choices the receiver must choose from in interpreting the messageNoiseNoise interrupts a communication channelby changing bits in the original messageincreases the probability that the wrong message will be receivedRedundancystandard solution for noise•more bits than required, or•multi-channelExampleLegend of Zelda: Minish CapMonsters are not all vulnerable to the same types of weapons10 different weapons(we'll ignore combinations of weapons)Encounter a new monsterwhich weapon to use?4 bits of unknown informationWe could try every weaponbut we could get killedExample, cont'dMessagesthe monster iconography contains messages•rocks and metal won't be damaged by the sword•flying things are vulnerable to the "Gust Jar"•etc.the game design varies the pictorial representations of monsters•knowing that these messages are being conveyedlearning to interpret these messages•is part of the task of the player•once mastered, these conventions make the player more capableOften sound and appearance combinea redundant channel for the informationInformation FlowPeople exchange information with a game systemto figure out options and outcomesBut a game system can use information flow internally as wellNorbert Weiner developed cybernetics to explain this type of systemCybernetics is an attempt to unify the study of engineered and natural systemsCybernetic 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 stateTwo 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•pendulumPositive Feedback Loop"excitation"As the state