Towards a Theory of Narrative for Interactive Fiction - MIT Media Lab
Towards a Theory of Narrative for Interactive Fiction - MIT Media Lab
Towards a Theory of Narrative for Interactive Fiction - MIT Media Lab
Transform your PDFs into Flipbooks and boost your revenue!
Leverage SEO-optimized Flipbooks, powerful backlinks, and multimedia content to professionally showcase your products and significantly increase your reach.
(WWWversion;paginationdiersfromoriginaltext) <strong>Towards</strong>a<strong>Theory</strong><strong>of</strong><strong>Narrative</strong> <strong>for</strong><strong>Interactive</strong><strong>Fiction</strong> SeanSmithJosephBates February20,1989 CMU-CS-89-121<br />
School<strong>of</strong>ComputerScience CarnegieMellonUniversity Pittsburgh,PA15213<br />
Thecurrentparadigm<strong>for</strong>syntheticrealitybasedinteractivectionfeaturesfamiliarkinds<strong>of</strong>worlds androughlysketchasystemarchitecturetosupportenrichedinteractivectionbasedonanalogy realisticallypresented.Thisapproachisunsatisfyinginthatitexcludesseveralinterestingclasses <strong>of</strong>worlds,suchasworldswheretheuserexperiencesthesubjectivereality<strong>of</strong>acharacterwitha worldssuchasthese.Toachievethis,wesurveycinematechniqueanddevelopatheory<strong>of</strong>narrative substantiallydierentpersonality.Wewishtoextendthecurrentparadigmtoincludeclasses<strong>of</strong> Abstract<br />
withlmtechniques.Thisworkissignicantbecauseitbringsusclosertoourgoal<strong>of</strong>making interactivectionintoarich,highqualityartisticmedium. S.SmithwassupportedbyanOce<strong>of</strong>NavalResearchGraduateFellowship. Theviewsexpressedinthispaperarethose<strong>of</strong>theauthorsalone.
1Introduction Intheseventies,researchersat<strong>MIT</strong>,Stan<strong>for</strong>d,andelsewherecreatedcomputer-simulatedDungeons andDragons-stylefantasyworlds,inwhichuserscouldghtmonstersandsearch<strong>for</strong>gold.Ona asZorkandnearlyeverythingelseproducedbyInfocom.Onatheoreticallevel,however,this practicallevel,thishackinggaverisetoawholegenre<strong>of</strong>adventuregames,suchasRogue,aswell (SR's)[8][21]?Whatkind<strong>of</strong>artisticexpressionispossible1throughinteractionwithsuchsynthetic workopenedupsomeinterestingresearchareas.Howcanwecreatehighqualitysyntheticrealities expression[6][7]? realities[9]?Whatdothesystemsbehindthesyntheticrealitieshavetobeliketoachievesuch<br />
<strong>of</strong>whichexistinggamesareprimitiveexamples;currentIFresearchatCMUconsists<strong>of</strong>imagining whatsomenon-primitiveexampleswouldbelike,buildingAI-basedSRsystemsthatmoveinthis direction,andpreparingtorecognizeanduseappropriateAItoolsastheybecomeavailable. usedbytheseexistingprimitivegames."<strong>Interactive</strong><strong>Fiction</strong>"(IF)refers2totheartisticmedium providingmanypowerfultoolswithapplicationsinworldsimulationandinteraction|toolsnot ThomasEdison'spioneeringmotionpictureexperiments).Theeld<strong>of</strong>articialintelligenceis Fromanartisticviewpoint,theseadventuregameswerequiteprimitive(butthensowere<br />
realisticallypresentedsimulatedworld.Suchsystemscanbeinteresting,butnumerousinteresting insidesomeothercharacter'shead|theuserinteractsthroughthisdierentpersonalityandpar- promising,theysuerfromacertainatness:theuserremainstheuser,wanderingaroundina aboutfullsensoryinteraction).Whilethesystems(realandimagined)comingout<strong>of</strong>thisworkare worlds,onplotmanagement,andonimprovingthebasicinteractiontools(whileidlyspeculating systemsliecompletelyoutsidethisparadigm.Considerworldswheretheuseristhehomunculus Todate,IFresearchershaveconcentratedprimarilyonimprovingthequality<strong>of</strong>thesimulated<br />
inspaceortime|theydonotadaptwelltothesimple"wanderinthis"approach. tiallyassumesit,<strong>for</strong>theduration<strong>of</strong>theIFsystem.Considerexperienceswithstorylinesnotlinear <strong>for</strong>world,plotandinteractiontoincludemechanisms<strong>for</strong>inuencingtheuser'smood3and<strong>for</strong> user.Inmanyways,thistask<strong>of</strong>selectingandorderingissimilartothat<strong>of</strong>lm-editing.We theory<strong>of</strong>narrative,atheory<strong>of</strong>howIFsystemsshouldselectandorderdetailspresentedtothe communicatinginwaysthatliebeyondthescope<strong>of</strong>ordinaryworldpresentation.Weneeda 1Chapters11and12<strong>of</strong>[25]presentaninterestingnon-technicaldiscussion<strong>of</strong>theseissues. 2HereatCMUwhenwereferto"interactivection"wemeanSR-basedinteractivection,asopposedtohypertext Inordernottoexcludetheseworlds,ourIFparadigmhastobeextendedbeyondmechanisms<br />
systems. 3Apparentlytherole<strong>of</strong>emotionalreactionisunderestimatedinliteratureaswell|see[23]. 1
cinematechniques.Wethenconsidertheenhancementsandconstraintsnecessary<strong>for</strong>adistributed exploitthissimilaritytoprovideabasicnarrativetheorybyanalyzingandadaptingsomebasic<br />
2.1Motivation toimplementtheseadaptedtechniques. 2Why:theNeed<strong>for</strong>AnotherDimension character-drivensyntheticrealityarchitecture(suchastheOZsystemindevelopmentatCMU[6])<br />
doingwhateveronewants|literallyandtakeitasthesinglesensiblearchitecture<strong>for</strong>IF.4 plotmanagement.Onemightinterpretthismodel|astagebuiltanywayonewants,withactors isLaurel'sthesis[21].DrawingheavilyonAristotle'sPoetics,LaurelanalyzesIFinterms<strong>of</strong>theater principlesandproposesacorrespondingIFsystem,completewithaplaywrightexpertsystem<strong>for</strong> Todate,themostseriousattempttoplaceIFinanartistic(ratherthanagame-playing)framework 2.1.1MagicHelmets<br />
logicitpleases;thechoice<strong>of</strong>whichdetailsarepresentedtotheuser,andhowandwhentheyare more.Rather,theworldinvolvedistheworld<strong>of</strong>thesyntheticreality,whichfollowswhatever presented,neednotbeconstrainedbytherules<strong>of</strong>ouruniverse.Thetheaterapproachexcludes worldswhichincorporatesuchalternatelogicsandpresentationmechanisms. theworldfollowsthelaws<strong>of</strong>physicsandtheviewerseeseverythingthathappensnearby,butno failstoexploitfullythepotential<strong>of</strong>interactivection.IFneednothappenonarealstagewhere Foranumber<strong>of</strong>reasons,wefeelthatthisapproachistoolimiting.Theliteraltheatermodel<br />
theuserneverceasestobehimself,inHamlet'sposition.WhatiftheuserisHamlet(atleast onewantsIFtobeamagichelmetthatwouldtriggertherightneuronssothatthewearerdreams partially)|whatiftheuser'smindismanipulatedbythesystemtotrytomaketheuserthink/feel someinterestingIFsystemsthatliesquarelyamongtheexcludedworlds.Supposeonedoesn't heissomeoneelseinanotherreality.LaurelusesexamplesfromHamlet;yetinthesesituations wanttoseeactorsonastage,orevenbeone<strong>of</strong>them(evenmakingupone'sownlines).Suppose Thelimitationsimposedbythetheaterparadigmareespeciallyranklingwhenoneenvisions<br />
likeHamlet,notjustexperienceHamlet'sobjectiveexperiences? 4Laureldoesnotappeartotakesuchaview,butneitherdoessheaddressparticularwaystobroadentheframework. Tomakethisvaguenotionalittlemoreconcrete,letusconsiderastorylinewithsomesimply 2
Cuckoo'sNest[19],thenarratorChiefBromdenisaninmate<strong>of</strong>amentalhospitalwhoregains stated,explicitgoalsachievablethroughbeingacharacter.InKenKesey'sOneFlewOverthe hissanityasaresult<strong>of</strong>interactingwiththerowdynewpatientMcMurphy.Thethrust<strong>of</strong>the novelisBromden'scure;Keseyillustratesthiscurebyshowingustheincreasingclarity<strong>of</strong>the narrator'sperception.Keseyplaysallsorts<strong>of</strong>trickstotrytoplacethereaderinsideBromden's mind.(Keseycommentedinaletterthat"youneedtotakethereader'smindplaceswhereithas whatreallychangesinBromdenisasupercialworld-lter,thewayexternaleventsandsensory whatbetterwaytoexperiencethestorythantobeBromden?CuckooasIFisaidedbythefactthat impressionsgetprocessedbe<strong>for</strong>ebeingfedtothehomunculus.ThesickBromdensuersfromfog episodes,muteness,hallucinations,andmistakenbeliefthathislarge,strongbodyisinfactfrail neverbeenbe<strong>for</strong>etoconvincehimthatthiscrazyIndian'sworldishisaswell."5)Inthisspirit, andweak.ThesickBromdendescribesthingswithcomparisonstomachinery,thehealthywith nature.6Anotherfeature<strong>of</strong>Cuckoothatmakesitconvenient<strong>for</strong>IFisthebasicirrelevance<strong>of</strong> Bromden'sactionstotheow<strong>of</strong>thestory. butalittlefurtherback.)ThechangesinDedalusarenolongerconnedtosensoryprocessing, [17]Joycesucceeds,byusingtextonly,inplacingthereadernotrightbehindacharacter'seyes, theintellectualdevelopment<strong>of</strong>theyoungStephenDedalus.(Indeed,inbothPortraitandUlysses Portrait<strong>of</strong>theArtistasaYoungMan[16].Writtenasstream-<strong>of</strong>-consciousness,thisnovelreports butdealratherwithdeeperthoughtpatterns.Whatkind<strong>of</strong>interactionmechanismsdoweneed toachievethiseectinIF?Oneimaginesacomputerdual<strong>of</strong>theuser'scharacter;theuserhasto SomethingthatisquiteinfeasibleasIFbutisstillchallengingtothinkaboutisJoyce'sA<br />
actinconsensuswiththisdual.Theremayverywellben<strong>of</strong>easibleanswerstothisquestion,but itisinterestingtothinkabout. 2.1.2IssuesRaised Consideration<strong>of</strong>thisvisionraisesanumber<strong>of</strong>issues,which,whilerelated,aresucientlyor- generality. thogonaltoallowsubstantialindependentresearch.Wepresenttheissuesinorder<strong>of</strong>increasing<br />
6[28],p.28,32.Also[24],pp.14-15 5[28],p.23. Theinnermosthomunculusshouldremainunaltered.InPortraitthereaderseesintoDedalus' mindinordertounderstandandjudgehispoint<strong>of</strong>view([18],p.45).Thevalue<strong>of</strong>this experiencewouldbedestroyediftheuserwerecompletelyDedalus;whilewewantt<strong>of</strong>oster 3
course,ifwe'vesucientlyconvincedtheuserhe'sHamlet,thentheuser(believingheis plotcanbelargelylinear.Amoreactiveusercharactergreatlycomplicatestheseissues.(Of deaf-mute(partiallyfeigned),Bromden'sroleinCuckooislargelypassive,sothemodeled thatitinhibitstheuser'sabilitytojudgeandappreciate. Wemustallowtheuseratleastanillusion<strong>of</strong>freewill,eveninthepresence<strong>of</strong>plot.Asa useridenticationwithacertaincharacter,wedon'twantthatidenticationtobesostrong<br />
aren'tjustabstractworldssucientlyinterestingtomotivateexplorationbytheuser.Rather, wehavespecicemotionalandmentalstateswewanttobringoutintheuser.Thesestates Thesyntheticrealitymusthavesometype<strong>of</strong>signicance.Thealternativeworldssuggested actingfreely)willdoexactlywhatHamletdid,thussimplifyingtheSR'splotspace.) needtobemappedout;therealm<strong>of</strong>ploten<strong>for</strong>cementhastodealnotjustwithhaving<br />
Thispaperpresentsresearchintothelasttwoissues. tal/moral/emotionalworld).(Inessence,weneedtomodelboththephysicalworldandsomeinvisibleunderlyingmen- Weneedmechanismstobringaboutinterestingmentalstatesintheuser. therightphysicaleventsoccurbutalsowithhavingtheusergettotherightmentalstates.<br />
ment."Thetheatermodelstressesrealismtoomuch.Itdoesn'tpersonallyinvolvetheuser.Whenobjectingtothetheaterparadigm<strong>for</strong>IF,itistemptingtouseterms"realism"and"involve- 2.2TheNeed<strong>for</strong>AnotherDimension<br />
immersedintosomeoneelse'ssubjectiverealitystressrealism?Afterall,theinteractionwouldfeel aworldwheretheuserremainshimselffullyinvolvetheuser?Doesn'taworldwheretheuseris morerealthanabe-yourself-in-another-worldsystem. However,itsoonbecomesapparentthatthesetermsbluragreatdeal<strong>of</strong>thepicture.Doesn't<br />
[15]faultanexperimentalcamera-behind-the-eyeslm<strong>for</strong>beingtooreal|theblinksandjostles somecharacter'scompletesubjectivereality?No.HussandSilversteininTheFilmExperience similarlyobscurestherealissuesbybeingoverlysimplistic.Dowereallywanttheusertoexperience recordedbythecameraaredistractingbecausewhilehumaneyesrecordthesethings,thehuman minddoesn'tactuallyseethem.HowBromdeneatshisfoodandwherehekeepshistoothbrush andwhetherheputssocksonbothfeetbe<strong>for</strong>eputtinghisshoesonaredetailsthatareentirely Ourinitialdescription<strong>of</strong>someinterestingbutexcludedworlds(suchasBromden/Cuckoo)<br />
4
sohecanseehowXandYchangewithcertainactions,andcanseethesymbolicaspects<strong>of</strong>the unimportant.Wedon'twanttheusertobeBromdenarbitrarily;wewanttheusertobeBromden hospitalconfrontations. aspects<strong>of</strong>asubjectiveexperience.Inordertodothis,userinteractionneedstooccuronthelevel accordinglytoincludethiscontext.Wethusneedtodevelopatheorytotodealwithinstalling andmanipulatingthiscontext. <strong>of</strong>thissignicance.Syntheticrealities(currently,physicalworldplusplot)mustbedeepened Whatwereallywanttoachieveintheexcludedworldsisthecommunication<strong>of</strong>certainsignicant<br />
patheticallyshort<strong>of</strong>theidealyou-are-theresensoryexchange.Isthisreallyaweakness?Huss modality<strong>of</strong>theuser/systeminteraction.Displayedtext,simplegraphics,andkeyboardinputfall andSilversteinobservethat"theart<strong>of</strong>thelmisbornout<strong>of</strong>thetriumphoverlimitationsinthe medium."7Suchastatementalsoholdstrue<strong>for</strong>theart<strong>of</strong>interactivection|theselimitationsare whatsetsIFapartfromothermedia,andbyfocusingontheselimitationswewillbeabletodiscover thenew<strong>for</strong>ms<strong>of</strong>artisticexpressionthatinteractivectionmakespossible.Inthisspirit,wecan SuchatheorycanconvenientlylltheprimaryweaknessLaurelseesinIFsystems:thelimited<br />
regardthenarrowcommunicationchannelasatool.Controllingthein<strong>for</strong>mationowbetweenthe SRandtheusercanbeapowerfulway<strong>of</strong>inuencingtheuser'smentalstate.("Languageisa Trojanhorsebywhichtheuniversegetsintothemind."8)Hence,thetheoryweneedisatheory <strong>of</strong>narrative:aset<strong>of</strong>valvesonthisnarrowchannelanddevicestoautomaticallycontrolthem. blinksandjostleswe'vealreadymovedawayfromthat|wehavesacricedsome<strong>of</strong>thestrictness inordertolettheuserachievesomegreaterunderstanding<strong>of</strong>thecharacter'ssituation.Inventive experiencesstrictlysubjectivereality(thatis,theuserisBromden).However,byeliminatingthe worldsbutsacriceall<strong>of</strong>thestrictness.Whatgreaterunderstandingswouldbecommunicated? IFresearchersmaywonderwhathappensifweusethenarrativetoolsproposed<strong>for</strong>theBromden Attachingthisaxis<strong>of</strong>narrativetoolstothebasictheaterparadigmcreatesawholenewspace<strong>of</strong> Aswehaveobserved,theexcludedBromden-styleworldswereclassiedasoneswheretheuser<br />
possibleworlds.Bromdenworldsarenallyadmitted;soareawiderange<strong>of</strong>worldswehaven't thought<strong>of</strong>yet. 8[18],pp.34-35. 7[15],p.145.<br />
5
3How:ImportingCinemaTechniques<br />
couldthengrowandbecomeuniquetoIF.(Thisapproachisnotnew|wheninventingcinema, 3.1BorrowingaKernel tionandcommunicationtricksfromothermedia.Althoughtransplanted,thiscoreonceestablishedRatherthantryingtobuildatheoryfromscratch,wedecidedtoexploreimportingmoodmanipula- D.W.GrithstudiedandadaptedliterarytechniquesusedbyDickens.)Theareasconsidered<strong>for</strong> harvestingincludedpoetry,psychology,advertising,lm,andmusic;JoelBloch(aCMUgraduate studentinEnglishwithparticularknowledge<strong>of</strong>lm,andamember<strong>of</strong>theCMUIFgroup)nally suggestedlm-editing.<br />
simultaneouseectivenessandthriftarewhatweneedinournarrativetools.Further,lmisquite adeptatcommunicatingwithinacontext<strong>of</strong>signicance.Thesamesceneeditedvedierentways canactuallybepresented.9Inlm,afewfacialexpressionsthathavenothingtodoreallywith canchangehisspeedandjumpbackand<strong>for</strong>thinthetext)anditisverylimitedinthedatathat presentation<strong>of</strong>dataisboundtorealtime(unlikethepresentationinanovel,wherethereader aperson'scharacterneverthelessmustserveascharacterization|andthey<strong>of</strong>tensucceed.Such Uponreection,cinemaisanappropriateparentmedium.IFissimilartocinemainthatits<br />
willpresentoneset<strong>of</strong>physicalin<strong>for</strong>mationbutvedierentmoodsandsets<strong>of</strong>deeperideas.This approachispromising|weneedtocatalogsomebasictoolsinlm-editingandtotryttingthem toIF. 3.1.1BasicCinemaTechniques Thefollowingcollection<strong>of</strong>standardlmtechniqueswasculledfromHussandSilverstein'sThe FilmExperience,anart-lmtexttakenatrandomfromtheshelvesatCMU'slibrary,andenhanced fromourownexperience,andquicklymentionsomepossibleapplications. throughdiscussionwithJoel.Experiencepresentsthetechniquesalongwithexamples<strong>of</strong>theiruse andtheresultingeectontheviewer.Wesummarizethese,occasionallyaddinganexampleortwo<br />
toconsider<strong>for</strong>presentation. 9Therelativepoverty<strong>of</strong>synthesisedworldsandinteractionmodeslimitstheamount<strong>of</strong>dataIFsystemsevenhave Lapdissolve([15],p.22).ThisisatransitionfromsceneXtosceneYconsisting<strong>of</strong>simultaneouslyfadingoutXandfadinginY.Thelapdissolveestablishesaconceptuallinkbetween thetwoscenes;inFrankensteinaburialisdissolvedintoagraverobbery. 6
Panshots([15],p.22).Inapanshot,thecamerasmoothlyscansthescene.Frankenstein alsousedthese|"whatnewhorrorwillthecameradiscover?"Panshotscouldalsobeused tions. Close-ups(closeshots<strong>of</strong>details)andcross-cuts(paralleldevelopment<strong>of</strong>physicallyseparated rarelyphotographedfromnormallines<strong>of</strong>vision."Unusualviewpointssuggestunusualsitua- topresentmaterial<strong>for</strong>whichsmoothnessisappropriate.<br />
scenes)([15],p.24).(D.W.GrithgotthesefromDickens.)Close-upsgiveasceneasense <strong>of</strong>detail,<strong>of</strong>reductionism.Cross-cutsallowthelmtoestablishlinksbetweenthescenes Strangecameraangles.([15],p.22)InFrankenstein,fearanduneaseareelicitedby"scenes<br />
theseproblems. presentedinparallel.<br />
Quickashbacks([15],pp.25,27).Briefbutimportantscenesfromacharacter'spastare Repetition<strong>of</strong>adevice([15],p.27).InHitchcock'sMarnietheleadcharacterhas<strong>for</strong>various replayedatselectedtimes.InTheLoneliness<strong>of</strong>theLongDistanceRunnertheobsessed theseproblems,suchchildrenshowupinthebackgroundatpointsinthelmsignicantto reasonssomepsychologicalproblemslinkedtoyoungblondfemalechildren.Tounderscore<br />
ousexamples.AsKane'smistresssings,thecamerapullshigher(mimickingthesoaring<strong>of</strong> whichallowsincidentsfromthepasttobepresentedinamannerwhichbetterstressestheir relevance.) Symboliccameramovementandpositioning([15],pp.30,37).CitizenKaneprovidesnumer- runnerkeepsrecallingtheface<strong>of</strong>hisdeadfather.Likerepeateddevices,repeatedashbacks<br />
hervoice)torevealtwostagehandsinthecatwalksshowingtheirdisapproval;thecamera becomeasort<strong>of</strong>"rhymeorrefrain."(Singularashbacksallow<strong>for</strong>non-lineartimesequence,<br />
providesomedeeperaestheticconsistency. linking<strong>of</strong>thingslikeimages,movement,andactionstotime.HussandSilversteinciteseveral examples<strong>of</strong>battleeldsandmarchingsoldiers;thepurpose<strong>of</strong>thetechniqueisapparentlyto shootsdownatSusan,<strong>for</strong>cingtheviewertoconsiderhercondescendingly.<br />
Conictingmovement([15],p.46).Asomewhatpretentiousexample<strong>of</strong>thisoccursinthe conclusion<strong>of</strong>Fellini's812,whereGuidoconfrontsandmakespeacewithhispast,whichconsists Visualrhythm([15],pp.42,43).Experienceusesthistermtodescribetheregular,coordinated<br />
<strong>of</strong>aring<strong>of</strong>people.ThesepeopledanceinacirclewhileGuidodancestheotherway;henally changeshisdirectiontocoincidewiththethat<strong>of</strong>theothers. 7
Distortion<strong>of</strong>naturalrhythms([15],pp.48,107).LindsayAnderson'sThisSportingLife featuresanightmarishrugbymatch.Thatthesceneisinslow-motionandwithoutsound enhancesitsnightmarishaspect. Zoom-freeze([15],p.52).Thecamerazoomsinonsomeimportantfacet<strong>of</strong>thesceneand freezesthere.Thistechniquelendsextraemphasistothatfacetbyarrestingtheviewer's Iris([15],p.59).Irisingtosomeimportantdetail|liketheanguishedmother'shandsina attention. courtroomwherehersonisontrial|meansphysicallymaskingouteverythingelseinthe scene.Thisissimilartotheclose-up(indeed,<strong>for</strong>purposes<strong>of</strong>ouranalysistheclose-upis subsumedbyirising)excepttheexclusion<strong>of</strong>thenon-emphasizeddetailsismoredeliberate. visualrealm<strong>of</strong>IF.However,theeect<strong>of</strong>almcanbegreatlyenhancedbyvisualallusion|Imagery.[15]hasawholechapteronthis,most<strong>of</strong>whichisnaturallyirrelevanttothenon- (Irisinginfactissomewhatarchaic,andisnot<strong>of</strong>tenseenincontemporarycinema.) HussandSilversteinciteechoes<strong>of</strong>Christ'spassagetoCalvaryinOntheWaterfront.Put simply,wecanobtaininterestinginheritancealongthelines<strong>of</strong>reference.Itwouldbeniceto duplicatethiseectinIF. Nearlysubliminal"ashshots"([15],p.108).Inthedevelopment<strong>of</strong>sceneX,thelmquickly<br />
Anderson'sIf...:thebookwormPeanutsallowsthevirileMicktolookthroughhistelescope, Momentaryexcursionsintosubjectivereality.AnexamplecomestomindfromLindsay importantscenessuchasthefuneralpyreviasuchashes.Themostextremeexample<strong>of</strong>this techniqueisprobablyFriedkin'suse<strong>of</strong>actualsubliminalshotstotrytoheightenthehorror <strong>of</strong>TheExorcist.10 ashessomeimageYthatrecallsoremphasizessomeimportantidea.EasyRider<strong>for</strong>eshadows<br />
agirlwithwhomheisinvolvedappearsandwavesathim.Itiscompletelybeyondthe focusedonthestars.Mickinsteadtrainsthetelescopeonawindowacrosstheway,where<br />
andrebellioninanEnglishboardingschool.Theoccasionalsubjectiveintrusions(notfollowinganyhardset<strong>of</strong>rules, like"blackandwhite=fantasy,"butowingorganically)contributetoawholethatstrikessome(suchasone<strong>of</strong>the authors<strong>of</strong>thispaper)aspowerfulvisualpoetrythatachievesseverallevels<strong>of</strong>resonance.Itstrikesothers(suchas 10Whethersubliminalsactuallyworkisanopenscienticquestion;[22]containsagoodsurvey<strong>of</strong>thissubject. 11ItisinterestingtoconsidertheaptlynamedIf...[3][27],asomewhatsurrealdiscussion<strong>of</strong>alienation,repression physicalreality<strong>of</strong>thelm<strong>for</strong>thegirltobeinthatbuilding,letalonetobeabletosee<br />
acertainhousemate<strong>of</strong>thatauthor)asuninterestingnonsense.Thevastdierencebetweenthesereactionsradically Mick;nevertheless,thescenehelpstocharacterizetheboysandisacceptableintheslightly<br />
demonstratestheimportance<strong>of</strong>makingtheusercom<strong>for</strong>tablewiththecontext<strong>of</strong>anon-realisticIFreality. experimentalcontext<strong>of</strong>thelm.11<br />
8
Remindingviewersthattheyarewatchingamovie([15],p.115).Experiencediscussesthe<br />
suggeststhattheconversationisn'tasimportantasitsounds,orthattheparticipantsare aSeriousIntimateDiscussion,exceptthecamerashowsonlythebacks<strong>of</strong>theirheads.This Contrastbetweenshotsandsubjectmatter([15],p.118).Godardpresentsacouplehaving heightensthesense<strong>of</strong>campandallowsdirectcommunication<strong>of</strong>characters'thoughts. inseveralWoodyAllenlms.Theseexamplesallfeatureabit<strong>of</strong>camp;use<strong>of</strong>thisconceit actors'asidestothecamerainTomJones;Joel(inconversation)citesasidesandsubtitles<br />
Presentingascenethroughasequence<strong>of</strong>myopicclose-ups([15],p.119).HussandSilverstein unnaturallydetachedfromorunware<strong>of</strong>itsimport. citealovescenepresentedassuchamosaicandclaimthetechniquerenderedthesceneeven Graduatepresentsone<strong>of</strong>Mrs.Robinson'sattemptstoseduceBeninthisfashionandthus Voiceovers.Joelcitesthetheory<strong>of</strong>narrationinlms|nonarrator,omniscientexternal allowstheviewersomersthandinsightintotheheady,aroused,andconfusedstateinwhich theincidentleavesBen. moreeroticasitprovidednosense<strong>of</strong>gestalt|<strong>for</strong>cingtheviewertousehisimagination.The<br />
3.2AdaptingtheseTechniquestoIF thein<strong>for</strong>mationspokenandindirectlythebeliefsandopinions<strong>of</strong>thespeaker. in<strong>for</strong>mationtotheuser;<strong>for</strong>example,character-as-narratorvoiceoverscommunicatedirectly narrator,characterasnarrator,etc.Each<strong>of</strong>thesehasitsownpurposesincommunicating<br />
Wenowwanttoconsiderhowthesetechniquescouldbeadaptedtoandimplementedininteractive currentlyproposedarchitectures;hence,be<strong>for</strong>ewecansensiblydiscusstheseimplementationswe needtodiscussbrieythebasearchitecture. 3.2.1BasicSyntheticRealityArchitecture ctionsystems.Theseimplementationsmayverywellrequireextensionsandmodicationsto<br />
de-emphasizesthemonolithicplaywrightcontrolinfavor<strong>of</strong>amoredistributedapproach[6][7][8]. distributedworld/charactermodel[21].AtCMUwearebuildingsuchanarchitecture|OZ|that actermodels.Theworldgraphindicatesrough3Darrangement,plusrelationshipsbetweenobjects Laurelproposesasyntheticrealityarchitecturethatcombinesaplaywrightingexpertsystemwitha Currently,anOZsyntheticrealityconsists<strong>of</strong>aphysicalworldgraph,objectmodels,andchar- 9
andtheirconnectivity;thecontents<strong>of</strong>theroomsarelistedwithcontainmentandotherstructures butwithoutexplicitphysicalcoordinates.Charactersarerule-basedentitiesthatoperateinparallel suchascontainment.InaDeadline-styleworld[5][10],thisgraphspeciestheroomsinthemansion chosenacts.Ploten<strong>for</strong>cementiscurrentlyembeddedinthebehavior<strong>of</strong>objectsintheworldand butalsoinlockstep:theyallperceive,thentheyallchooseanact,thenthesystemper<strong>for</strong>msthe principlesincludemaximizingtheliveness<strong>of</strong>theworld;thatis,wewanttominimizetheinclusion intherulesdrivingthecharacters(inthe<strong>for</strong>m<strong>of</strong>scheduledactions,<strong>for</strong>example).Ourguiding <strong>of</strong>author-suppliedtextsothattheworldcanreactproperlytothegreatvariety<strong>of</strong>possibleuser actions. thecharacters,userinteraction,andworldmodel,anddevelopingbettermethodstoexpressand en<strong>for</strong>cetheplot.Ourultimategoalisacomputer-assistedwritingenvironmentwithwhichauthorscaninteractdirectly(ratherthanthroughprogrammers)tocreatehighquality,artistically legitimateinteractivection. RelatedresearchatCMU(besideswhatthispaperpresents)includesexploringwaystoenrich<br />
imaginehowtheimplementedtechniqueshouldaectuserinteractionandthenconsidertheset<strong>of</strong> 3.2.2ImplementingtheTechniquesinIF Howcanweimplementthelmtechniquesininteractivection?Toanswerthis,wemustrst<br />
sampletechnique. tectureextensionsnecessary<strong>for</strong>theentireset.Weintroducethiscorebydiscussingamotivating mechanismsnecessarytobringaboutthisbehavior.(Noticethatthissetshouldincludenotonly mechanismstoproducethisbehavior,butalsomechanismstodecidetoproduceit.) StoryContext Theimplementationexampleswilllargelybedrawnfromthesame(hypothetical)world,loosely Ouranalysis<strong>of</strong>implementingsomelmtechniquespresentedearliersuggestsacore<strong>of</strong>archi-<br />
things.Noteveryoneexposedbecomesinfected.Many<strong>of</strong>theinfectedpeopleappearquitenormal brokenoutintown.Infectedpeoplebecomeinsaneandgoaroundkillingpeopleanddoingbizarre inbetweentheirrandomacts<strong>of</strong>violence. inspiredbyGagne'sdiscussion[13]<strong>of</strong>GeorgeRomero'slmTheCrazies.12Astrangeplaguehas<br />
itispresented. 12Indeed,GagnemakesthepointthatthelmiseectivebecauseRomerouniesthelm'ssubjectwiththeway Thingsareinastate<strong>of</strong>chaos.TheNationalGuardisrunningaroundherdingpeopleintothe 10
mentalstateslabeled"sane"and"insane."Alesserthemeistheineptnessandinecacy<strong>of</strong>the scienticandmilitaryestablishments,thosebastions<strong>of</strong>authorityandorder. asociallevel,theproximity<strong>of</strong>normallifetodisorder;onanindividuallevel,theproximity<strong>of</strong>the result<strong>of</strong>somemishapinthemilitary'shandling<strong>of</strong>abiologicalweapon. gym;soldiersinwhitesuitsandgasmasksareeverywhere.Itisrumoredthattheplagueisthe<br />
defyingmartiallawandscienticestablishmentbysneakingarounddiscoveringtheplague'scause Theusercharacter(UC)isOurHero,ayoungscientistconnectedtoalocaluniversitywhois Theoveralltone<strong>of</strong>thestoryischaos.Oneoverridingthemeisthefragility<strong>of</strong>modernlife:on<br />
andpursuingacure. Supposehe'sgothishandsonsomeclassiedmilitarydocumentandistryingtoextractthe relevantin<strong>for</strong>mationwhilehidingbehindatree.Soldiersareeverywhere;thereareonlyafew minutesbe<strong>for</strong>eOurHerowillbediscoveredandhavethedocumentremovedfromhispossession. ASampleTechnique:ArchitecturalImplications<br />
surroundingareaandthenlettheuserreadthedocumentuntilheiscaught. ImagineascenewhereOurHeroistryingtodosomethingagainstachaoticbackground. OncetheUChashidden,aconventionalIFsystemwouldsummarizewhat'sgoingoninthe presentsascene<strong>of</strong>disorderandchaos.Soldiersaremarchingaround,shoutingorders astheyrounduptheinhabitants.Some<strong>of</strong>thetownspeoplestruggle.SweetoldMrs. herknittingneedles. Buckmansitsknittingonherfrontporch.Asoldierapproachesher;shekillshimwith Youbegintoreadthedocument.Youonlyhaveafewminutes.Thetowngreen<br />
sequence<strong>of</strong>detailswouldhelpconveytheurgency<strong>of</strong>theUC'ssituation;thelack<strong>of</strong>overallcoherence wouldmimicthelack<strong>of</strong>orderinthetownandthefailure<strong>of</strong>theUCtogureoutthecauseand cure<strong>of</strong>theplague. Inasituationlikethis,themyopicclose-uptechniquewouldbeappropriate.Thestaccato Theuserinteractswiththedocument...<br />
"Whatthehell'sgoingon?Youcan'tdothis!" asentenceortw<strong>of</strong>romthedocument Openthedocumentandread. Youareholdingthedocument.Youknowthatyouonlyhaveafewminutes. 11
Mrs.Buckmanknitsonherporchacrosstheway. asentence "MOVESQUAD17OVERBEHINDTHEPOSTOFFICE!" Ayouthiskickedintosubmission. asentence AsoldierapproachesMrs.Buckman. "I'msorrysir;wehaveourorders."Thesoldierclubstheman.<br />
gazebo. TheAmbersonfamilyandsomefriendsscreamwhentheyseethecorpsesinthe<br />
"Mybaby!Howcouldtheyhavedonethis?" "JENKINS|CHECKTHOSETREESOVERTHERE!" asentence Teargasislobbedintothechurchpicnic. asentence "WHEREARETHOSEROUNDSWENEEDED?" Mrs.Buckmanissplatteredwithblood.<br />
thesurroundingenvironment.TheseelementsarechosenandassembledautomaticallybytheIF What'sgoingonhere?Theuser'sperusal<strong>of</strong>thedocumentisinterleavedwithdetailsfrom plantedinthesoldier'schest,ashecrawlsthroughthedaodils. asentence... Astrand<strong>of</strong>yarnfromtheunravelingsweaterisanchoredintheknittingneedles<br />
abletoimplementthistechnique,theEditoralsoneedssomemechanisms<strong>for</strong>choosingtoimplement details.13WhyshouldtheEditorchoosethistechniqueandnotsomeother?Inadditiontobeing it.HowdoestheEditorgetahandleonthesurroundingenvironment?Previouslyweimagined theinterleaving?Weneedsomekind<strong>of</strong>Editorthattakescare<strong>of</strong>selectingandpresentingthese systemsothattheresultingsequenceisgratingandlackscoherence. Eventhisquickanalysissuggestsanumber<strong>of</strong>necessaryarchitecturalconstraints.What'sdoing<br />
theenvironmentmodeledbyaphysicalworldgraph,withcharacterinteractionsarbitratedand astheEditor'sinteractionwiththeSRmaynotbethispassive|thesportscasteranalogymayonlybeappropriate per<strong>for</strong>medbyacentralloop.Thisarchitecture(perhapswithdecentralizedcontrol)isagoodbase screensandselectinginrealtimewhichviewtotransmit.Asweshallsee,thisconceptualizationisslightlyawed, ifthesportissomethinglikerollerderbyorpr<strong>of</strong>essionalwrestling. 13Onemayconceive<strong>of</strong>theEditorasasportscasterdescribingahockeygame,orasaTVdirectorlookingat16 12
scenelocationsaresensorilyaccessiblefromthelocationwheretheUCis.Foranother,what's interactionarbitrationprocedureattachedtoit,responsible<strong>for</strong>theinteractions<strong>of</strong>thecharacters happeninginscenesbeyondtheperception<strong>of</strong>theEditorisessentiallyirrelevant(moreonthat later).Interaction,likecharacterposition,islocalized.Thissuggests14thateachcharactershould betiedtotheparticularnodeintheworldgraphcorrespondingtoitsphysicallocation(theEditor insomesensewouldridepiggy-backontop<strong>of</strong>theUC).Each<strong>of</strong>thesenodeswouldthenhavean <strong>for</strong>implementingmyopicclose-ups.Foronething,theEditorneedstobeabletodiscoverwhat<br />
Editorcycles(selectingandcollatingdataandsendingitontotheuser)wouldrequireasmalllocal traversal<strong>of</strong>thegraphtoseewhat'sgoingonaroundit. attachedtothatnode.Bothinteractioncycles(gatheringandprocessingbasicuserreactions)and<br />
betweenthemallhaveveryphysicalbases.It'sveryintriguingtoconsiderwhatotherkinds<strong>of</strong> ResearchisalreadyunderwayhereatCMUintoenrichingabasicscenegraphtoindicatemore complexphysical(thepostoceisacrossthetownsquarefromthepark)andsensoryrelationships (itispossibletohearveryloudnoisesthroughthewall).15Boththesescenenodesandthelinks in<strong>for</strong>mationcouldbeembeddedhere:edgesbetweennodescontainingparallelcharacters?The graphissupposedtomakelocalthein<strong>for</strong>mationneeded<strong>for</strong>interaction|whatin<strong>for</strong>mationbesides Thisidea<strong>of</strong>alocaltraversalraisestheissue<strong>of</strong>whatrelationsshouldbelocalinthegraph.<br />
sensorydatamightbeneeded<strong>for</strong>interactioninasyntheticreality?<br />
actiondata.Weseethatthisissuewillrequireagreatdeal<strong>of</strong>thought.Inourmotivatingexample, datapiecesarechosen<strong>for</strong>theirshockvalue|weneedtheabilitytoper<strong>for</strong>mroughsemanticanalysis, <strong>for</strong>m.Hence,weneedtoinstallsomecomputer-palatablesystem<strong>of</strong>knowledgerepresentation. Schank'sconceptualdependencymachinery[26]suggestsitself,butthisisonlysuitable<strong>for</strong>basic beabletotalkaboutwhat'sgoingonthere.Sincethisin<strong>for</strong>mationnotonlyiscomputer-generated butalsoneedstobemanipulatedandsemanticallyanalyzedbythesystem,itcannotbeintext WhataretheseelementsthattheEditorischoosing?Each<strong>of</strong>theneighboringscenenodeshasto<br />
whateveradatapieceis.WealsowanttheEditortoselectasetthatisnotquitecoherent|hence weneedanestimate<strong>of</strong>howcompletelyadatapiecerepresentswhat'sgoingoninascenenode. sothattheEditorcancallheuristicevaluationfunctionstoestimatehowshockingorsoothingor Noticethatcoherenceisnotastaticnotion|"what'sgoingon"involveseventsoverawindow<strong>of</strong> time.Noticealsothatonecouldpresentcompletein<strong>for</strong>mationaboutascene,butwithsucient fragmentationitwillstillbeincoherent.Makingtheseevaluationfunctionssimpletocomputewill beamajorissueindesigningourknowledgerepresentationsystem. isanaudiolinkbetweenthetelephoneinJuan'soceandthetelephoneinSu-Yuen'soce.Anaspect<strong>of</strong>aphysical worldgraphthatourscenegraphfailstoinheritispermanenceovertime. 14Infact,theOZarchitectureconvenientlymovedinthisdirection,independent<strong>of</strong>theresearchinthispaper. 15Onechallengeishowtodealwithtelephones,<strong>for</strong>example|that<strong>for</strong>theduration<strong>of</strong>thephoneconversationthere 13
produceisnotaset<strong>of</strong>discretepiecesbutratherasinglehierarchy.Thedeeperapieceinthis <strong>of</strong>allthedata-piecescomingout<strong>of</strong>thatnodesuggeststhatwhatwereallywantthenodeto hierarchy,themoredetailedthein<strong>for</strong>mation:therootmightindicatethecharacterspresent,the theconversation,thenexttheactualsentencesexchanged.Abenet<strong>of</strong>usingsuchhierarchiesis computationaleciency|weimaginethatfrequentlyonlyafewnodesinthishierarchywillneed rstgeneration<strong>of</strong>childrenthattheyarehavingaconversation,thenextgenerationasummary<strong>of</strong> Theneedtodeterminehowoneparticulardata-piecefromagivenscene-nodetsinthecontext<br />
againstpathologicaluserswhowantcuttheawaythecouch'supholsteryandscatterthestung specifyingallinadvanceorcalculatingeverythingateverysimulatedmoment,alsomayprotectus systemsketches.Besidesyieldingcomputationaleciency,thisprincipleallowsgreaterthematic aroundtheroom|theusercandiveridiculouslydeepinthedetailhierarchy,ifhesochooses. tobeexpanded.Thisillustratesaprinciple<strong>of</strong>lazyevaluationwhichwillapply<strong>of</strong>teninourIF redwhenitneedsredobjects.Settingupasystemtogeneratedetailswhenneeded,ratherthan exibility|notspecifyingthecolor<strong>of</strong>thecouchinadvancemeansthattheEditorcancolorobjects<br />
cyclesnow,one<strong>for</strong>UCinteraction(<strong>for</strong>interactionlocaltothescene-graphnodewheretheUC duration<strong>of</strong>atechnique)shouldbequiteabitlongerthantheusertick.TheEditorshouldbe ormakesthetechniqueunnecessary<strong>for</strong>somereason.We'veintroducedatleasttwodierentclock quiteafewsimulatedclockticks.16ThissuggeststhattheEditor'sbasiccyclelength(theexpected preparedtodiscontinuethetechniqueiftheusertakessomeactionthatviolatessomeprecondition suchasmyopicclose-upsalsoraisesthesetimeissues.Thetechniqueaspresentedencompasses Coherenceevaluationraisedtheissue<strong>of</strong>timewindows.TheEditor'sper<strong>for</strong>mance<strong>of</strong>atechnique<br />
extendthearchitecturetodealwithmultipleusers.) muchin<strong>for</strong>mationtheEditorneeds,andnomore.(However,thisapproachwillmakeitdicultto interactioncyclebutquickerthantheEditor-techniquecycle;wewantthesystemtoproduceas is),andone<strong>for</strong>theEditor.Whichoneshouldbeusedintheinteractionmonitors<strong>of</strong>alltheother scene-graphnodes?Theprinciple<strong>of</strong>lazyevaluationwouldsuggestsomethingslowerthantheuser-<br />
actualimplementationwouldbeinfeasible.Quiteafewothersseempossible,however. SomewhatFeasibleTechniques Whenweconsideradaptingthelmtechniquesoutlinedearlier,wendthat<strong>for</strong>some<strong>of</strong>them<br />
seconds<strong>of</strong>simulatedtime. 16A"tick"isabasicuserinteractioncycle,incurrentOZterminology.Itisusuallyintendedtorepresentafew TheDecisionMechanism Earlierwejustglossedoverthemechanism<strong>for</strong>decidingtoper<strong>for</strong>msometechnique.Thebasic 14
approachwehadinmindwasconsideringthetechniquesasaset<strong>of</strong>operators,eachwithitsown set<strong>of</strong>resultsandusermoodtrans<strong>for</strong>mations,andeachwithitsownset<strong>of</strong>necessaryandsuggested preconditions.Editingisthenplanningapaththroughmood/plotspaceusingtheseoperators. Onemightuseclassicalplanningtechniquesormorerecentideasontheories<strong>of</strong>activity([1][2])to butlittleexplorations<strong>of</strong>ar<strong>of</strong>mood.Inkeepingwiththeprinciple<strong>of</strong>makingoursystemcharacter- implementthedecisionmechanism. andwhatitisaboutthemthattheEditorischecking.Therehasbeenresearchonploten<strong>for</strong>cement mood/plotspaceinwhichtheuserwanders.(Wecanachievegreater"liveness"inthesystemand greatercomplexityinmoodspacebyconcentratingonthefunctionsgeneratingthespacerather driven,webelieveitwouldbebettertomaintainaUCmoodmodelratherthanhavealargeexplicit thantheexplicitspacegraph.)Goal/planin<strong>for</strong>mation17couldbeincorporatedintothismodelas Thisapproachraisestheissue<strong>of</strong>howexactlyusermoodandplotareembodiedinthesystem,<br />
whatmoodtheuseroughttobeledto. todate.ItistheseregistersthattheEditorcheckstodeterminewhatmoodtheUCisinandthus acharactermodelthatmonitorstheworldandkeepssomesystem-visibleset<strong>of</strong>moodregistersup systemthentakesthisin<strong>for</strong>mationandbrewsup(usingsomeunspeciedbutwonderfulAIengine) well.Thismodelwouldbeessentiallythesamemodelusedtoimplementothercharacters.18The systemrstgathersin<strong>for</strong>mationfromtheauthorregardingacharacter'sdestinyandpersonality quirks,whatsort<strong>of</strong>moodsandattitudeswouldbetriggeredbywhatsort<strong>of</strong>worldevents.The<br />
explicitplotgraph.PerhapscertainEditoractionsshouldbedemon-triggered|whenfoohappens, maximizelivenesswe'dliketoinstallsomeAIenginethatwatcheswhathappens,ratherthanan beddedinaUCmodel,andsoimaginesomeplotmonitormightbenecessary.Again,though,to analarmintherelevantcharactermodelgoeso,andthemodelinterruptstheEditorandin<strong>for</strong>ms town)thattheEditorshouldknowaboutbutcannotreasonablybeexpectedtodiscoverduringthe it.Thisdevicewouldbeneeded<strong>for</strong>events(suchascriticalplotdevelopmentsontheotherside<strong>of</strong> Wesuspectthatsomedataimportant<strong>for</strong>shapingtheuser'sexperiencewillnotbeeasilyem-<br />
character'sexistenceinithavesomepre-ordainedmeaning.Ascharactersdon'tnecessarilyknoworevenintendtheir limitedlocalsearchitper<strong>for</strong>ms.(Theuse<strong>of</strong>suchdemonsisanalternativetoinstallingnon-physical<br />
goals,wesuggestthat"destiny"besubstituted<strong>for</strong>"goal"insuchdiscussions. cannedplotin<strong>for</strong>mationthatcannotbeeasilyembeddedinthecharacters'destinyboxes.Hence, thematic-linkedgesinthescene-graph.)<br />
charactersonthey. 17Frequently,characters'goalsandplansareartifacts<strong>of</strong>theworld'sauthorandthefactthattheworldanda 18Thisapproachwouldfacilitatemulti-user(orzero-user|see[8])IFandsystemswheretheusercanchange Wesuspectthatdespiteourintentiontomakethesystem"live,"wemayneedtoincludesome<br />
15
werefertoaplotboxaswell|weusethistermtostressthatthisismorearegisterorset<strong>of</strong>ags thananexplicitplotgraph(somethingantitheticaltothespirit<strong>of</strong>liveness).Perhapsmuch<strong>of</strong>the plot-boxcontrolcanbebuiltintothedemon-triggeredEditoractionsmentionedearlier. mented,butnoeasilyimplementedset<strong>of</strong>heuristictriggerscanbespecied.Use<strong>of</strong>eachtechniqueislinkedtodeeperaestheticvisionbeyondthescope<strong>of</strong>themachine.Hence,weseearoughdichotomyarisingbetweenthedirectlyautomatabletechniques(thatwouldbesuppliedaspart<strong>of</strong>a kernelpackage)andtheoneswhosecallingmechanismsrequiresubstantialcreativeinputfromthe world'sauthor(thesewouldbesuppliedascustomizableoptions). Itsoonbecomesapparentthatmany<strong>of</strong>thelmtechniquescanbeeasilyadaptedandimple-<br />
AutomatableTechniques<br />
another.SupposeOurHerowantstowalkfromthetreetoMrs.Buckman'sporch. (fromourcurrentprimitiveperspective)touseitwhentheUCisgoingfromonesceneto Here'sasituationwheretheEditormusttakeintoaccountinteraction|itonlyseemssensible LapDissolve. Myopicclose-ups.Seeearlierdiscussion.<br />
Anaiveapproachistokeepreportingthecontinuouslyvaryingscene. WalktoMrs.Buckman'sporch.<br />
Thisapproachgreatlycomplicatesscene-graphmaintenance|justimagineallthepossibilities Youpassthebleachersandthedeadboyscout. Youcrossthestreet. YouwalkuptoMrs.Buckman'sporch.Shesmilessweetlyandsays"hello." Youhearthepanickingchurchpicniccrowdototheleft. Youwalkthroughthes<strong>of</strong>tballeld.<br />
interaction.Butbynotbeingexplicitlyannounced,thesetransitionswouldappeartothe <strong>for</strong>interactionastheUCwalks.Wecouldgetaroundthisbysometimesdecidingtowhoosh theUCrightfromscene-nodetoanother(asinchutesandladders)andnotallowing<strong>for</strong>any userastroubling"deadspots." Anexplicitwaytoper<strong>for</strong>mthistransitionistoremovethedeadspot|cutfromonescene toanother.(Indeed,thedirectcut,somethingtootrivialtoincludeinthelmtechnique list,shouldprobablybelistedhere.)Explicitcuttingalsoprovidesanicewaytomaskthe granularityinherentintheunderlyingsyntheticreality. 16
signicantwillbecommunicatedbymixingthetwoscenes.Maybeayoungguardhadjust discoveredOurHero,whowas<strong>for</strong>cedtostrugglewiththeguardandknockhimout.The Whywouldwewanttodoalapdissolveratherthanadirectcut?Perhapswhensomething innocentmen.Suggestion:theUC'snoblymotivatedactioninknockingoutathreatening guardisdisturbinglysimilartothemurderjustcommittedbythemadMrs.Buckman. UCthendecidestowalkovertoMrs.Buckman'sporch.Linkandcontrast:violenceagainst peeling. nose. Thewhite-suitedsoldieristwitchinginthedaodils. Theyoungguardliessprawledinthebushes. Theyoungguard'seyesarerolledback.Bloodtricklesout<strong>of</strong>his WalktoMrs.Buckman'sporch.<br />
Thetwistedyarnattachedtotheknittingneedlesiscakedwithblood. Herturn-<strong>of</strong>-the-centuryhouseischarming,butupcloseyoucannoticethepaint<br />
scenehassomedata-piecesthatareverysimilartopiecesintheUC'ssourcescene.To Toimplementsuchalapdissolve,theEditorjusthastorecognizethattheUC'sdestination makethingslessconfusing<strong>for</strong>theuserwecouldsomehowsignalthatallthesedetailsarenot perhapsopeningasecondwindowtocorrespondtothesecondlocationmaybemoreeective). occurringinthesameplace(intheexampleaboveweuseddierentfontstoindicatethis; Mrs.Buckmansmilessweetlyandsays"hello."<br />
Weoncemoreseetheneed<strong>for</strong>ahierarchy<strong>of</strong>data-pieces:similaritycouldthenbedetermined bycomparingsomehigherlevelaspects<strong>of</strong>thishierarchy.Per<strong>for</strong>mingthetransitionjust consists<strong>of</strong>selectingafew<strong>of</strong>thesesimilarpiecesandinterleavingtheirpresentation.<br />
preprogramming("beonthelookout<strong>for</strong>this"). howwecouldhavetheEditorrecognizethesedeeperlinksintheabsence<strong>of</strong>explicitauthor Lapdissolvescouldalsooccur<strong>for</strong>morecomplexreasonsthanjustsimilarity<strong>of</strong>details|<br />
Panshots.Wecancommunicatetheproximitythemesinthissamplestorywhenpresentinga TorecognizesuchlinkstheEditorneedstobeabletoevaluatethescenes,andtoexamine theoverallplotstructureandtheUC'sgoalandpersonalitystructure.Itisdiculttosee perhapstherearethematiclinks(suchastheUC/Mrs.Buckmancomparisonwesuggested).<br />
presentationjarringaswell. descriptionbysmoothlyscanningthetownsquare'sjarringmixture<strong>of</strong>4th<strong>of</strong>JulyAmericana andchaoticviolence.Mixinggenerallysoothingdetailswithoccasionalshockersmakesthe 17
faceburiedinhisapronashestumblesaboutblindly.Thescenebecomeslargely woodenbleachersononeside,withasignsayingtheyweredonatedbythetown's Furtherdownthepathisthepicnicarea.Acharcoalreisburning,andsome hamburgersaresizzlingaway.Amanwithacleric'scollarandachef'shathashis RotaryClub.There'sadarkreddish-brownsmearonthesign,andbelowitliesthe crumpledbody<strong>of</strong>aboyscout.TherearesomeemptyCokecansontheground. Youduckbehindthetree.Beyondthetreeisthes<strong>of</strong>tballeld.Thereare<br />
obscuredbytheclouds<strong>of</strong>teargas.Sneakeredfeetpoundthroughthegrass,among Smilingsweetly,Mrs.Buckmanwipesthebloodfromherface.Asweaterather thespilledpotatosalad,s<strong>of</strong>tballequipment,andyelpingpuppies.Acrossthestreet isoldMrs.Buckman'shouse,withhercarefullytendedgardenandwindchimes. feetisunraveling|astrand<strong>of</strong>yarngoesdowntheporchsteps,aroundthemilkbox,<br />
interruptedatrandommomentsbyhighlyshockingpieces. piecesthataremoderatelycoherentandtthetemplate<strong>of</strong>agenerallysoothingpiecesequence Toimplementsuchpanning,theEditorscansthesensorilyaccessiblenodesinsomenatural order|perhapsleft-to-rightwhenviewedfromtheUClocation.19Fromthesenodesitselects throughthedaodilstoaknittingneedleanchoredinthechest<strong>of</strong>awhite-suited soldierlyingthere.<br />
Cross-cuts(in-body).Basically,cross-cuttingispresentingtwoscenesinparallelbyalternating viewertodigestbothsets<strong>of</strong>images,andtounderstandthattheseareseparatescenesbeing presented. OurIFsystemislooselyboundtotheprinciple<strong>of</strong>presentingthesubjectivereality<strong>of</strong>the imagesfromeach<strong>of</strong>them.Thisalternationisslowanddeliberate|theintentionis<strong>for</strong>the<br />
actuallybeobservedfromthesamephysicallocation.(Laterweexamine"out-<strong>of</strong>-body" cross-cuts.) ConsideroncemorethesituationwheretheUCishidingandtryingtoreadquicklyastolen thisquestion.Hereweconsider"in-body"cross-cutting|presentingtwoscenesthatcould UC.Theidea<strong>of</strong>cross-cuttingpromptsonetoask,inlight<strong>of</strong>thisprinciple,whethertheUC<br />
document.PerhapstheEditorneedstoraiseasense<strong>of</strong>urgencyintheuserwithoutinstilling istobeintwoplacesatonce.Twotypes<strong>of</strong>cross-cuttingarisefromthetwoanswersto<br />
19Thissuggeststhatscenenodesneedtocontainpositionalin<strong>for</strong>mationaswell. scenewithinsight<strong>of</strong>theUC,andinterleavepiecesfromthatscenewithpiecesfromtheUC asmuchpanicasatechniquesuchasmyopicclose-upswould.Asolution?Chooseashocking nodeinsuchamannerthatbothscenescomeacrossinasomewhatcoherentmanner. 18
white-suitedsoldierapproachesher. and,carryingherknitting,walksovertohim. sentencefromdocument<br />
ThesoldierstartstospeaktoMrs.Buckman.Smilingsweetly,shestandsup sentencefromdocument<br />
Mrs.Buckmanplungestheneedlesintothesoldier'schest.Bloodspurtsonto AcrossthegreenMrs.Buckmansitsonherfrontporch,knittingasweater.A<br />
Zoom-freeze.PerhapstheEditorneedstodrawtheuser'sattentiontosomeobjectordetail. thesmilingoldwoman. sentencefromdocument<br />
isimportantenoughtobementionedatallshouldbebuiltintotheSRsomehow).Wecould yogurtintheroom.Normallytheyogurt'spresencewouldbementionedinpassing(thatit Inoursampleworld,maybeitisthepeoplethathavebeeneatingyogurtthathaveremained uninfected.OurHeroistalkingtoyetanotheruninfectedperson,andnoticesthatthereis Thesoldiercrawlsaway,trailingyarnfromtheunravelingsweater.<br />
sentenceinboldface,orsomethinglikethat. Whenactuallyimplementingthistechnique,theEditorcollectsthedatapiecesitisconsidering<strong>for</strong>presentation.ByexaminingtheUC'sdestinyboxandtheoverallplotbox,theEditor drawtheuser'sattentiontototheyogurtsentencebyfreezingtheoutput<strong>of</strong>text<strong>for</strong>several seconds(ifthatwouldn'tbeconfusedwithtimemanipulation),orperhapsbydisplayingthe recognizesthatacertainiteminthiscollectionwouldbeagoodcandidate<strong>for</strong>zoom-freeze emphasis.(Perhapsthatrecognitionwillgivethatpiecehigherpriority<strong>for</strong>presentation.) Whenandifthatpieceispresented,itispresentedemphasized. Iris(<strong>for</strong>emphasis).Likezoom-freezing,irisingisawaytoemphasizeacertaindetail.Irising howeveremphasizesacertainpieceinascenetothedeliberateexclusion<strong>of</strong>theotherpieces.<br />
iris<strong>for</strong>emphasis|here. user'smoodby<strong>for</strong>cinghimintosometype<strong>of</strong>tunnelvision.Wedealwiththe<strong>for</strong>mer|using andtheemphasizedaspect|weonlypresentenough<strong>of</strong>thebigscenetolettheuserknowit's there. Weseetwopurposespossible<strong>for</strong>irising:tostresssomeaspect<strong>of</strong>ascene,ortoinuencethe Conceptually,wecanlookonthisasanunbalancedcross-cutbetweenthebigglobalscene<br />
Returningtooursampleworld,perhapsit'svitallyimportantthattheuserrecognizethe importance<strong>of</strong>theyogurtandgetonwithsolvingthemystery<strong>of</strong>theplague,sowhentheUC 19
walksintohealthyLibby'skitchentheEditorsays"YouhaveenteredLibby'skitchen"and<br />
mayinfacthappenisthatademoninascenenoderecognizesthatthingXisgoingonand per<strong>for</strong>mstheappropriateaction(whichwemodeledasacross-cut).(Weimaginethatwhat overallplotboxandtheUC'sdestinyboxthatthingXneedstobestressed.TheEditorthen andpicksitup. Animplementation<strong>of</strong>irising<strong>for</strong>emphasismighthavetheEditordecidebaseduponthe thenlaunchesintoadiscussion<strong>of</strong>theyogurt,notlettingupuntiltheusernallywalksover<br />
TechniquesRequiringSignicantAuthorCustomization boxdo.) Cross-cuts(out<strong>of</strong>body).Thistechniqueinvolvespresentingtwoscenes|atleastone<strong>of</strong>which thatitmightbeimportant,soeitheritin<strong>for</strong>mstheEditorordemonsinthedestinyandplot<br />
Inoursampleworld,perhapsanotherscientistdiscoversavaluablecluebutismistakenly isbeyondthesensoryreach<strong>of</strong>theUC|totheuserviacross-cuts. communicatethistotheuser|stressingtheblunderingtheme,lettingtheuserknowthatthe Itmustbecleartotheuserthatthissceneishappeningsomewhereelse.Wecanusean newlylatescientist'sworkwasontherighttrack,etc. alternatefont,orperhapshaveanotherwindowopenup.Inthatwindow... killedbe<strong>for</strong>eitcanberevealed.Onecanconceive<strong>of</strong>manyreasonswhyitisimportantto<br />
scribblesdownnotesinhisnotebook. gunshimdown. Jonesputsafewdropsonaslideandexaminesitunderamicroscope. "Thisisit!"saysJonesexcitedly."Thehumancellsremaineduntouched!"He Asoldierturnsthecorner.Jonesapproacheshimwiththetesttube. Thechemistrylab.Pr<strong>of</strong>essorMaitJonesremovesatest-tubefromanincubator. ThenervoussoldierperceivesJones'agitatedtest-tubewavingasathreat,and<br />
expectthiswillbethecase.Hence,the<strong>Lab</strong>nodehastohaveenoughintelligencetorealize "hey,itmightbeimportant<strong>for</strong>theusertoknowwhat'shappeninghere"andgotapthe (oneimagines"importantparallelcharacter"linksinthescene-graph),wecannotreasonably Whileitwouldbeverynice<strong>for</strong>theEditortobeabletoseethe<strong>Lab</strong>nodefromtheUCnode outside. Twoothersoldiersthrowthebody|includingnotebook|intoapyresetup<br />
Editorontheshoulder.Thissuggeststhatweneedscoutingdemonsattachedtoeachscene 20
demonsneedtobehighlycustomized<strong>for</strong>individualworlds. onceithascalledattentiontoitself,inordertopresentthatnode'sdatapiecesinanongeneric fashion.(Onealsowonderswhateectscanbeachievedbylettingtheuser'sactionsinthe NotealsothatthereisnothingtopreventtheEditorfromscanningoutfromthe<strong>Lab</strong>node, important.Wefearthatbuildingcompletelygeneralwatch-demonsistooinfeasible;such node,demonssucientlyaware<strong>of</strong>plotandeventsanddestiniestoknowwhenthingsare<br />
appropriatetimes. PerhapstheUChadagirlfriendwhodied<strong>of</strong>theplague.Sayshehadredhairandadistinctive somemoodordeepidea;wethenbesurethatthisdetailshowsupinthesimulatedworldat lab?) Repetition<strong>of</strong>device.Inthistechniqueweestablishalinkbetweensomephysicaldetailand UCnodeinuencetheeventsintheout-<strong>of</strong>-bodynode.WhatiftheUCrunsovertoMait's<br />
accent.TheUCistraumatizedbythedeath.Duringstressfultimes,we'llhavetheUCnotice thatcertainvictimsaroundhimhaveredhairorasimilaraccent...<br />
importantscenethathasalreadyoccurred|eitherintheSRitsel<strong>for</strong>be<strong>for</strong>ethesimulation ThistechniqueisdierentfromndingandreportingMait'slab.Thegirlfriend'sdeathisan started.Eitherway,itissucientlysignicanttobestoredsomewhere.Perhapsweneeda redhair. readingthedocument<br />
SignicantEventListinthesystem'sUCmodel.Eventsthatoccurpre-simulationwillbe Overbythemonument,asoldierclubsayounggure.Scarletbloodstainsthe<br />
evaluationinworldsimulation,sotheEditorcanimposeoccurrences<strong>of</strong>redhairwhenitneeds atraumaticsceneintheSEListcanbeintroduced.(Hereweseeoncemoreaneed<strong>for</strong>lazy too|"watch<strong>for</strong>thegirlfriend'sdeath...").IftheEditordecidestheUCisfeelingespecially them.) stressed,itcanexaminethedata-piecesit'spresentingtoseeiftheappropriatedetailsfrom hardwiredin;othereventsneedtoberecognizedandadded(perhapstheseneedhardwiring<br />
Quickashbacks.PerhapstheUCsawhisgirlfriendkilledwhen,driveninsanebytheplague, sheattackssomeone.Whenhewitnessesotherviolenceagainstothervictims,thissceneis brieyreplayed. gunshimdown. ThenervoussoldierperceivesJones'agitatedtest-tubewavingasathreat,and 21
SuchaashbackcanbeusedineventssuchasJones'deathtosuggesttheUC'sfearthat thinksthatperhapssomecharacterisinfectedandwillhavetobekilled. perhapshisgirlfriendwasmistakenlykilled.ItcanalsobeusedininstanceswhentheUC Theshotringsoutandshecrumplestotheground.Butthehandyouheldso<strong>of</strong>ten won'treleasetheknifeevenindeath.) (Shebrushesherredhairout<strong>of</strong>hereyes.Smiling,sheraisesthebutcherknife.<br />
PerhapstheUCwastheonewhopulledthetrigger.Theashbackcanbegraduallyextended20 toincludethisin<strong>for</strong>mation.Thegrowth<strong>of</strong>theashbackcanreectthegrowth<strong>of</strong>theUC's anxiety.MaybethediscoverythatitwastheUCthatkilledher,alongwithsomepiece <strong>of</strong>in<strong>for</strong>mationthatprovesinhindsightthatshewasn'tinfected(shewasdefendingherself againstanattackeroutsidetheUC'sview),canparalleltheUC'sdiscovery<strong>of</strong>acure. Toimplementthistechnique,weoncemoreneedtoassumetheEditorhasahandleonthis criticalscene.Wesuspectthatthishandlecanonlybeprovidedbyauthorhardwiring.The<br />
dinatedlinking<strong>of</strong>thingslikeimages,movement,andactionstotime. alsorequiresauthorhardwiring.) Rhythm.Whatisrhythm?HussandSilversteinusethistermtodescribetheregular,coor- theEditorwantstosuggestcertainUCfeelingstotheuser,whencertainkinds<strong>of</strong>scenesare beingpresented,andwhencertainpreselectedeventsoccur.(Thislatteractivationapproach ashbackusesdiscussedabovesuggestseveralwaysthatashbackscanbeinvoked:when<br />
It'sfairlyeasytoseehowtheEditorcouldimplementdeliberaterhythmicbehavior:itwould pickaclass<strong>of</strong>objectsthataregoingtoberhythmical(suchasredthingsorplummeting householdappliances)andanobject-timepatternandthenen<strong>for</strong>ceit.Oncemoreweseea AmorechallengingquestioniswhytheEditorwouldwanttousethistechnique.Itseemstous need<strong>for</strong>lazyevaluation,sotheEditorcanndredthingswhenitneedsthem.<br />
world'sauthor,whowouldembedherbiasesintheserules. It'salittleeasiertoseehowshallowuses<strong>of</strong>rhythmcanbejustiedandautomated.Therst eect<strong>of</strong>thelm|notsomethingeasilyspecied<strong>for</strong>automation.These"deeper"purposes slant<strong>of</strong>rules)intheEditor.ThedeepcreativedecisionswouldbemadebyaparticularIF thatthepurpose<strong>of</strong>thistechniqueinlmistiedwiththosedeepissues<strong>of</strong>theoverallaesthetic shouldeventuallybeincorporatedashigherlevelrules(ormeta-rules|rulesspecifyingthe<br />
20ExtendedashbacksarealreadyusedinacurrentIFsystem|Disch'sAmnesia[11]. thingsaroundhavemeaning:theytellhowtheghostfeelsabouttheUC(alternatively,the status<strong>of</strong>theUCintheachievement<strong>of</strong>hisgoal<strong>of</strong>exorcisingtheghost).Theauthormay examplethatspringstomindisAnderson'sghostworld[4].Theghost'sepisodes<strong>of</strong>throwing 22
amood/timemap(sothatthefrequency<strong>of</strong>thrownobjectsslowsdownwhentheUCsays therightthings,orsothatthefrequency<strong>of</strong>thethrownobjectsisfasternowthanitwasthe lasttimetheghostwasthrowingthingsbecausetheghostisangriernow)anduseit.The Editorreadstheghost'sattitudeintheintheghost'smoodbox,orintheUC'sdestinybox, orintheoverallplotbox. featurestherepetition<strong>of</strong>similaractions(datapieces?),andactivatesarhythmscheme|pick wishtoputsomerulesintheEditorthatrecognizewhentheUCisinasituationwhich<br />
thestream<strong>of</strong>therealityisatechnique(distortion<strong>of</strong>naturalrhythms)discussedlater.Note Intheabovediscussion,thetimestreaminwhichtheseeventsarerhythmicallyembeddedis realtime(thatis,timeastheuserexperiencesit).Changingtherelation<strong>of</strong>thisstreamto howeverthatifthisrelationischanged,thentheuse<strong>of</strong>thisrhythmmethodimpliesthatthe alteredtimestreamwillaecttheworld(theSR),notjusttheuser'sexperience<strong>of</strong>it.(Ifthe userisexperiencingplummetinghouseholdappliancesat0.5Hz,thentheseappliancesneed toplummetat0.5Hzrealtimenomatterhowfastorslowrealtimebecomeswithrespect Symboliccameraposition.InatextualmediumsuchastheIFsystemswe'reconsidering, whatistheequivalent<strong>of</strong>asymboliccameraposition?Wehaveconcludedthatitisacertain totimeinthesimulation.)<br />
ToimplementsuchtonalcontrolinasystemwithcurrentNLprocessingtechnology,wecannot isstentorian,andhestridesratherthanwalks. toneordescriptiveviewpoint.Perhapsacertainocerishighlycharismatic.Almmight communicatehisprowessandleadershipbyshootingupwardsathim|healwaysappearsas<br />
tothecharacterorobjectinvolvedatagspecifyingthecustomizedvocabularyandstyle thisocer.However,iftheauthorcan<strong>for</strong>eseesuchtoneadjustmentsthenshecanattach justadjustsomecontrolvariablesonalterthroughwhichwesenddata-piecesregarding animposinggiant.Intext,wecouldconveythisfeelingbyappropriatewordchoice|hisvoice<br />
acrowd<strong>of</strong>people(thechurchpicnicstampede?)allrushingtheotherway.Besidesbeing somedeeperrelationships.Inourplaguestory,perhapsOurHerohastoghthiswaythrough physicallynecessary,thiscouldbesymbolic<strong>of</strong>OurHero'srelativelyuniquereactionthe appropriatetothatcharacterorobject.Ifthischaracterappearsfrequentlythenthetag needstobesucientlyrichinordertoavoidhavingtheresultingeectseemrathersilly. Conictingmovement.Thepurpose<strong>of</strong>thistechniqueistoconveythroughphysicalopposition plague,orsomethinglikethat. Weimaginethisisanother<strong>of</strong>thedeepertechniquesthattheauthorwouldhavesetexplicit rules<strong>for</strong>,accordingtoherowncreativemind. 23
couldsetuptheinteractionlawsintheSRitselftoseethatthissort<strong>of</strong>thinghappensoccasionally.Perhapswehaveplotmanagers,withngersintotherelevantcharactermodelsand Thereareseverallevelstoimplementthis,andwhichisbestisnotatallclear.Theauthor aglobalplotbox,attachedtoeachscene-node.Alternatively,wecouldtrytodosomething symbolicopposingmotionoccurswhenevertheEditorwantsit. andmakesureitisreported.Conceivablywecouldevenuselazyevaluationtoensurethat withtheEditortorecognizewhenthereisopposingmotiongoingonthatcouldbesymbolic, per<strong>for</strong>medbytheEditor.Anyuse<strong>of</strong>symbolismindeepSReventsraisesthisissue. ThePlotManagerapproachseemsalittlemorereasonable,asusingthistechniquemay requiredeepmanipulation<strong>of</strong>theSR,nottheshallow(ornonexistent)manipulationusually tobeattacked.OurHeroseesthedangerbutCloseFriendisunaware.Forsomereasonthe onlywayOurHerocanwarnCloseFriendistorunacrossthesquaretotheFriend.Butit's SupposeOurHeroseesacrossacrowdedsquaresomecloseassociateorfriendwhoisabout Distortion<strong>of</strong>naturalrhythms. toolate. IntheSR,thishappensinjustafewseconds.Wecouldpresentitthatquickly. footballcoach.Thecoachholdsanax,andseemsreadytoswingitatFriend. AcrossthesquareyouseeCloseFriend.Behindhimstandsthehighschool Hecannothearyou.Coachstartsswingingtheax. Shout"Lookout!"toCloseFriend.<br />
<strong>of</strong>thehorror)byslowingdownthepresentation<strong>of</strong>therun.Maybeevenwe'dwanttocross Wecouldincreasethesuspense<strong>of</strong>thisscene(andtheuser'sfeeling<strong>of</strong>impotenceintheface cutbetweentheUCrunningandthecoachswinging. Yourun. Youreachyourfriendjustasthecoach'saxhasdecapitatedhim. Runacrossthesquare.<br />
footballcoach.Thecoachholdsanax,andseemsreadytoswingitatFriend. Hecannothearyou.Coachstartsswingingtheax. AcrossthesquareyouseeCloseFriend.Behindhimstandsthehighschool Yourun: Step.(thesedetailsarefedoutslowlyandregularly) Shout"Lookout!"toCloseFriend. Runacrossthesquare. 24
Step. Theaxmovescloser. Step. Theaxheadisonlyafootfromyourfriend'sneck. Step.<br />
hierarchy<strong>of</strong>data-pieces<strong>for</strong>thissceneisgrownfardeeperthanusual).PossiblytheEditor You'renearlythere.Theaxbreakstheskin.<br />
needstodosomethingtoblockinteraction(oratleastmakesuretheusercan'tdoanything Toimplementthis,theEditorjustslowsdowntheow<strong>of</strong>timeandmagniesdetails(ie,the Step.<br />
Slowingdownthepresentationwouldfreeupthecomputationpowernormallyusedtomain- thatdoesn'tttheslowmotioncontext). Youarrive.Yourfriend'sfreshlyseveredheadplopsdowninfront<strong>of</strong>you.<br />
tainalltheout-<strong>of</strong>-sightscenes,sowecoulddosomegarbagecollectionnow.Whatifwespeed Subliminals.Thepurpose<strong>of</strong>usingnearlysubliminalashesistosuggestquicklysomemood uptime?Thenit'spossiblethatout-<strong>of</strong>-sightscenemaintenancewillbestarved(iftheUCis justrocketingaroundthenscenesdon'tneedtobemodeledasrichly,true,butadjustment inthatdirectionisstilllimited). orideawithouthavingtoembeditinthelinearprogression<strong>of</strong>theSR. Oncemoreweseetheneed<strong>for</strong>acompletehierarchy<strong>of</strong>clocksandphasesandticks. PerhapsOurHeroisafraidhe'llbecomeinfectedandgoarounddoinghorriblethings.Occasionallyawindowcanpopupbrieyinwhichthisfearisvisualized. scanningtheUCbox<strong>for</strong>traumaticmemories;theitemsandtheiractivationconditionswill It'seasytoseehowrulescanbesetuptoleadtheEditortothistechniqueinordertoexpress andunwieldy.Unlikestandardashbackfodder,theseitemscan'tbeenumeratedbyjust somemoodoridea.Theproblemisthatthedomain<strong>of</strong>thingsthatcanbeashedislarge soakedwithblood. Youstandsmilingholdingthebutcherknife.Thecu<strong>of</strong>yourannelshirtis<br />
needtobehardwired. 25
Wecouldtrytogodirectly<strong>for</strong>subliminalinuencebyashingmessagesonthescreen<strong>for</strong>, say,asixtieth<strong>of</strong>asecond. Shouldsubliminalsactuallywork,thisapproachwouldheightentheuser'stensionandfear Peoplegettingshotrightandleft...<br />
sationbyJoelBloch(WoodyAllen)allfeatureabit<strong>of</strong>camp.Use<strong>of</strong>thisconceitheightens throughdirectsubconscioussuggestion. It'sonlyIF.ThelmexamplesprovidedbyHussandSilverstein(TomJones)andinconver- ash:You'renext.21<br />
out<strong>of</strong>contextandaddressingtheuserdirectly(perhapsbecausetheEditorwastoldbyaplot thesense<strong>of</strong>campandallowsdirectcommunication<strong>of</strong>characters'thoughts. WhatwouldthistechniquelooklikeinIF?Adirectadaptationwouldhavecharactersstepping Canthistechniquebeusedoutside<strong>of</strong>acampcontext?Wedon'tthinkso(butwe'resure<br />
theirrules<strong>of</strong>interaction(thisbehavior<strong>of</strong>coursewouldbeprogrammedintotherules<strong>of</strong> demonthatit'simportant<strong>for</strong>theusertolearnthein<strong>for</strong>mationthischaractercanreveal). Amorecreativeapproachwouldpokefunatthelimitations<strong>of</strong>IF:havingcharactersdiscuss someonewillthink<strong>of</strong>away).<br />
InfeasibleTechniques overusewoulddestroyitseectiveness). Wesuspectthatthistechniquewillonlybeusefulinasmallnumber<strong>of</strong>IFworlds(afterall, fetches(perhapstomasksomelengthysearches). interaction),orhavingthenarratingvoicejokewiththeuserabouthavingtogodosomedisk<br />
imagination. toacceptthesejudgmentsbutrathertoregardthemaschallengestothereader'screativityand tationswouldbetoodicultorunwieldy.Aswithalllimits,however,weencouragethereadernotThesearetechniques<strong>for</strong>whichwecannotconceiveadaptations<strong>for</strong>IF,orwhoseIFimplemen- 21ThisexamplewassuggestedbyPeterWeyhrauch.26<br />
omniscientexternalnarrator,characterasnarrator.Thisisaninterestingissuetoconsiderin Voiceovers.JoelBlochexplainedtousthetheorybehindnarratorsinlms|nonarrator, relationtointeractivection.Narrationiscrucialtosuchtext-basedsystems|whosevoice isitthatkeepsaddressingtheuser?
Thingssuchascommentarybyacharacterwithinthestoryfallundersuchtechniquesas"it's onlyIF."Butsomethingwehavenotconsideredisattachingapersonality,withquirksand Suchanapproachtonarrationrequiresbotheectivenon-narrativecommunicationandpow- thattheuserissucientlycertain<strong>of</strong>theunderlyingtruthtoperceivethesubjectivity. <strong>of</strong>acharacterinthestoryopensupsomeinterestingavenues<strong>for</strong>communication,provided attitudes,tothenarratingvoice.Havingthenarrationoccurfromthesubjectiveviewpoint<br />
asense<strong>of</strong>unease,<strong>of</strong>disorder. Strangecameraangles.Thepurposebehindstrangecameraangles(orviewpoints)toheighten erful"live"personalitysimulationandNLgeneration,all<strong>of</strong>whichmakesuslabelthistechniqueasinterestingbutquitebeyondthescope<strong>of</strong>whatweexpecttoachievewithOZ. Wecouldreportthestampedeatthechurchpicnicfromgroundview:dust,toweringgures, raisesawavytest-tube.Shotsringout. Throughthebeakers,Jones'faceisdistortedandgraybeardtintedyellow.<br />
fallingpotatosaladmeteors. falls. Darkyellowstainsappearontheback<strong>of</strong>Jones'lightyellowlabcoat.Thebody Aripplinggureinatintedyellowsuitappearsbehindhim.Jones'yellowarm<br />
tobuildintoanaturallanguagegenerator)wouldqualifyastheequivalent<strong>of</strong>"strangecamera Thesetwoexamplesareentirelyvisual|whattextualtechniques(thatwouldn'tbetoohard angles?" Howtoimplementthis?WecouldjustgliblysaythattheEditor,knowingthatitneedsto structureprocessorthattakesasinputaset<strong>of</strong>structuresandsomeFooandproducesthe maketheuseruneasyorsomething,decidestopresentthedatapiecesfromanangleFoo. twistedpiecesrequired?That'smoresatisfying,butisitfeasible? Iris(exclusionary).Aswementionedearlier,analternativeuse<strong>of</strong>irisingistointroducea Shouldthescene-nodesberequiredtospitoutdatapiecesnotonlyrelativetosomeincoming edge,butalsotoarbitraryFoo?That'snottoosatisfying.Shouldwerequiresomesemantic WeneedtotwistthesepiecestoreectFoobe<strong>for</strong>egeneratingnaturallanguagefromthem.<br />
feeling<strong>of</strong>tunnelvision.Maybewewanttheusert<strong>of</strong>eellikehe'sstumblingaroundblindin somedangeroussituation,soratherthanhearingaboutthevariousstampedingpeoplesurroundinghim,theuseristoldabouthisshoesandwhatthey'restandingon.Thisdescription isinterruptedfrequentlysotheusercanbetoldhe'sjustbeenbumpedinto. 27
Wedon'tseeatallhowtoautomatetheprocess<strong>of</strong>selectingwhichirrelevantdetailonwhich meaningsattachedthestandardlibraryimage.Userprocessing<strong>of</strong>thisconnectionisfrequently inastandardlibrary<strong>of</strong>images,sothatthemeaning<strong>of</strong>agivensceneisenhancedbythe toiris. Imagery.Thepurpose<strong>of</strong>imageryisclearenough|allude(visuallyorotherwise)tosomething<br />
withthebizarrethingsthathavebeengoingon.WeborrowfromasimilarsituationinDylan lifewithdisaster,wewanttohavehersaysomethingveryproperandordinarytocontrast Theclosestthingwecanthink<strong>of</strong>isliteraryallusion. OurheroisgoingtospeaktoMrs.Buckman.Tohelpcommunicatetheproximity<strong>of</strong>normal onanearlysubconsciouslevel.<br />
Thomas'AChild'sChristmasinWales. Whenwe'redealinganon-visualmediumlikeIFitisverydiculttoper<strong>for</strong>mimageallusion.<br />
andtheEditorcanscanthelibrarytoseeifthere'sastandardimagewhichtsone<strong>of</strong>the decidethatitwantstocommunicatefooanditwantstodothatthroughsomegivenset<strong>of</strong> datapieces.Itistemptingtoproceedbysayingthatalibrary<strong>of</strong>standardimageswillexist Howtoimplementthiskind<strong>of</strong>allusion?Presumably,theEditorhasenoughin<strong>for</strong>mationto youlikesomethingtoread?"Shesaystherightthing,always. YouwalkuptoMrs.Buckman'sporch.Shesmilessweetlyandasks"would<br />
Ulysses).Sadly,wesuspectthatrenderingthisanythingmorethanadreamrequiresgreater thetextstyle(onethinks<strong>of</strong>thepowerthistechniquegivestothe"Oxen<strong>of</strong>theSun"chapterin tobecustomized<strong>for</strong>eachSR|seemsquiteambitious. Anevenmoreambitiousapproachistoembedthereferencenotjustintheimagesbutalsoin onlywaytoautomatethissort<strong>of</strong>thing.Butbuildingupsuchalibrary|whichwouldhave data-piecesandcarriesmeaningthatcontributessignicantlyt<strong>of</strong>oo.Infact,thatseemsthe<br />
howtheUCpicksupabutcherknife,smilessweetly,andkills.Thewindowthenvanishes. beinfected.TheUCwalksintohealthyLibby'skitchen.Anewwindowpopsup,presenting Tocontinuetheexampleused<strong>for</strong>nearlysubliminalashes,theUCfearsthathemighthimself dexteritythancurrentNLprocessingwillprovide.<br />
SuchfantasiesaredeeplytiedtotheSR|they'renotsomethingtheEditorcanjustsupercatefantasiesandemotions<strong>of</strong>theUCbydirectexperience.Momentaryexcursionsintosubjectivereality.Thepurpose<strong>of</strong>thistechniqueistocommuniimpose.Thus,thecriticalquestiontoaskisnot"dotheothercharactersknowthisfantasy 28
ishappening?"butrather"howcanweemploythecharacterandrealitystructuresandinteractiontoolstocreatethisfantasywithoutdestroyingthetheobjectiverealitystateinthe SR?"Therealcharacterscannotbeaware,buttheremustbetwinswhoprovidenotonly awarenessbutthecompletefabric<strong>for</strong>analternatereality. ThisviewsuggeststhatthesealternaterealitiesshouldbemodeledbyalternateSR's|by spawningasub-reality.Theinteractionrulesandoverallplotboxwouldalldependonthe<br />
memories<strong>of</strong>thealternativerealities?Howdowemaintaincontinuity?Whathappensifwe work<strong>for</strong>awideclass<strong>of</strong>alternativerealities|notjustUCfantasies.Butwhatisthescope<strong>of</strong> Thismechanism,wheretheEditorcalls<strong>for</strong>anexcursionintoanalternativereality,would embeddedseamlesslyintotheuser'sexperience|wewouldn'thavetoopenawindowand announce"attentionshoppers:thisisafantasy!" UCcharacterboxinthemainSR.Ifthisisdonewellenough,fantasysequencescouldbe<br />
trytointroducemultipleusers? Implementation<strong>of</strong>subjectiverealitiesisindeeddicult,butwefeelitdeservesmuchex- Contrastbetweenshotandsubjectmatter.Thepurpose<strong>of</strong>thistechniqueistosuggestthat ploration.AsIFisuniqueinitspotential<strong>for</strong>interactivedream-logicepisodes,wefeelthat thingsmaynotbewhattheyseem. Theonlywaywecanseetoimplementthiswouldbetochangelanguagestyleandmood. exploitingthispotentialisessential. Giventheprimitivestate<strong>of</strong>ourcurrentnaturallanguagegenerators,wedon'tthinkthis<br />
includedinthestandardparadigm.Wedidthisbyexaminingsomeelementarylmtechniquesand 4Conclusions Wehavepresentedacollection<strong>of</strong>ideasonnarrative<strong>for</strong>IFsothatBromden-styleworldsmaybe approachisfeasible.<br />
about?Whatdothecharacter-modelsneedtomodel?Whatkind<strong>of</strong>AIarchitecturescanbeused becomearchitecturespecications.Whatexactlyisrequired<strong>for</strong>thedata-piecemachinerywetalk <strong>for</strong>theEditor?Anotherset<strong>of</strong>issuesarethedistributionquestionsraisedbylocalizinginteractions inthescene-graph.Howarewegoingtoworkoutthetime-cyclehierarchy? sketchingpossibilities<strong>for</strong>architecturetoimplementthesetechniques. Muchworkremainstobedone.Foronething,weneedtoreneoursketchessotheyactually<br />
29
thisartifact?Imagineahierarchy<strong>of</strong>intertwinedSR's(similartothetangledlevels<strong>of</strong>realityinthe model<strong>of</strong>aat,realisticsyntheticrealityandaddedadimension<strong>of</strong>(<strong>for</strong>want<strong>of</strong>abetterterm) onesinglerealisticSR,withmaybesomedream-sequencesub-SR'sbuiltin.Whatifweeliminated aectivesignicancetoit.Thismodelstillcarriesanartifact<strong>of</strong>thetheaterparadigm|thereis canweimport?HowcanwediscovertechniquesuniquetoIF?Inthispaperwehavetakenthe lmTheSingingDetective)oranSRthatisitselfaspirituallandscapebasedsolelyonaective Asmentioned,weonlydrewonsomebasiclmtechniques.Whattechniquesfromotherareas<br />
<strong>for</strong>mat.Manyresearchers(suchasLaurel[20]andseveralpeoplehereatCMU)arealsotryingto signicanceandnotonphysicsornarration(asseemstobethecasewiththerealitiesinthenovels <strong>of</strong>WilliamS.Burroughs). yettheideaswe'vesuggestedonlydealwiththetwomostgeneral<strong>of</strong>thefourissueswesawthis desireraise.(Thetechniqueswe'vesuggestedmayallowtheusertobeBromden,butcertainlynot Hamlet.)Soinadditiontoexploringtheterritorywe'vestakedoutinthispaper,weneedtopress furtherintothefrontier. moveawayfromthismodel.Thedesiretobreakawayfromthis<strong>for</strong>matwasourinitialmotivation; Thetheory<strong>of</strong>narrativewe'vedevelopedstillrevolvesaroundauser-drivenadventuregame<br />
Theauthorsaregrateful<strong>for</strong>thediscussionandsuggestionsprovidedbytherest<strong>of</strong>theCMUInter- 5Acknowledgments active<strong>Fiction</strong>group:PennyAnderson,JoelBloch,MerrickFurst,BryanLoyall,MaggieMcCarey, Thisisonlythebeginning.<br />
BalasNatarajan,MarcRinguette,andPeterWeyhrauch. 6References 1.Agre,PhilipandDavidChapman."Pengi:AnImplementation<strong>of</strong>a<strong>Theory</strong><strong>of</strong>Activity." 2.Agre,PhilipandDavidChapman."WhatarePlans<strong>for</strong>?"Cambridge,Massachusetts:<strong>MIT</strong> 3.Anderson,LindsayandDavidSherwin.If...alm.NewYork:SimonandSchuster,1969. ProceedingsAAAI-87SixthNationalConferenceonAI. ArticialIntelligence<strong>Lab</strong>oratoryAIMemo1050,September1988. 30
6.Bates,Joseph."TheOZCharacterSimulator."Pittsburgh:CMUIFSeminarNotes,Spring 5.Bates,Joseph."AnAnalysis<strong>of</strong>Deadline."Pittsburgh:CMUIFSeminarNotes,Spring1988. 4.Anderson,Penny."ExercisingtheOZCharacterMechanism."Pittsburgh:CMUCSD(internal),2November1988. 9.Bates,Joseph."WorldsasanExpressiveForm."Pittsburgh:CMUIFSeminarNotes,Spring 8.Bates,Joseph."SyntheticRealities."Pittsburgh:CMUCSD(draft),1987. 7.Bates,Joseph."SomeSimpleMindsinOZ."Pittsburgh:CMUIFSeminarNotes,Spring 1988.<br />
12.Eisenstein,Sergei.(tr.JayLeyda.)FilmFormandTheFilmSense.Cleveland:Meridian 11.Disch,Thomas.Amnesia.SanMateo,Cali<strong>for</strong>nia:ElectronicArts,1986. 10.Deadline.Cambridge,Massachusetts:Infocom,1982. Books,1967. 1988.<br />
15.Huss,RoyandNormanSilverstein.TheFilmExperience.NewYork:DellPublishing,1968. 16.Joyce,James.APortrait<strong>of</strong>theArtistasaYoungMan.NewYork:TheVikingPress,1976. 14.Hobbs,JerryR."CoherenceandCo-Reference."CognitiveScience,1(1979),67-82. 13.Gagne,PaulR.TheZombiesthatAtePittsburgh.NewYork:Dodd,Mead,andCompany, 1987.<br />
18.Kenner,Hugh."ThePortraitinPerspective."inT.E.Connolly(ed.)Joyce'sPortrait: 17.Joyce,James.Ulysses.NewYork:VintageBooks,1961. 20.Laurel,BrendaK."ReassessingInteractivity."TheJournal<strong>of</strong>ComputerGameDesign,1:13, 19.Kesey,Ken.OneFlewOvertheCuckoo'sNest.NewYork:Signet,1962. 21.Laurel,BrendaK.<strong>Towards</strong>theDesign<strong>of</strong>aComputer-Based<strong>Interactive</strong>FantasySystem.Ann CriticismandCritiques.NewYork:Appleton-Century-Cr<strong>of</strong>ts,1962. pp.7-10. Arbor:UniversityMicrolms,1986. 31
22.McIver,Tom."BackwardMasking,andOtherBackwardThoughtsaboutMusic."TheSkep- 23.Miall,DavidS."Aectand<strong>Narrative</strong>:AModel<strong>of</strong>ResponsetoStories."Poetics,17,pp. ticalInquirer,13:1,pp.50-63.<br />
25.Rheingold,Howard.Tools<strong>for</strong>Thought:ThePeopleandIdeasbehindtheNextComputer 24.Porter,M.Gilbert.TheArt<strong>of</strong>Grit:KenKesey's<strong>Fiction</strong>.Columbia:University<strong>of</strong>Missouri Press,1982. 259-272.<br />
28.Tanner,Stephen.KenKesey.Boston:TwaynePublishers,1983. 27.Sussex,Elizabeth.LindsayAnderson.London:StudioVista,1969. 26.Schank,R.C."ConceptualDependency<strong>Theory</strong>"inR.C.Schank(ed.)ConceptualIn<strong>for</strong>mation Processing.North-Holland,1975. Revolution.NewYork:SimonandSchuster,1985.<br />
32
Change language