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    ARTIFICIALCREATIVITY:

    ASyntheticApproachtotheStudyofCreativeBehaviour

    ROBSAUNDERS,JOHNS.GERO

    TheKeyCentreofDesignComputingandCognition

    DepartmentofArchitecturalandDesignScience

    UniversityofSydney,NSW,2006,Australia

    e-mail:{rob,john}@arch.usyd.edu.au

    Abstract.Wepresentanovelapproachtothecomputationalstudyofcreativity, called Artificial Creativity. Artificial Creativity promotesthe study of the creative behaviour of individuals and societies inartificialsocietiesofagents.Itissimilartotheapproachtothattakenby Artificial Life researchers involved in developing computational

    models.We presenta frameworkfor developingArtificialCreativitysystems as an adaptation of Lius dual generate-and-test model ofcreativity. An example implementation of an Artificial Creativitysystem is presented to illustrate the potential benefits of our newapproachasawayofinvestigatingtheemergentnatureofcreativityinsocieties of communicating agents. Finally, we discuss some futureresearch directions that are possible by extending the abilities ofindividualsandstudyingtheemergentbehaviourofsocieties.

    1.Introduction

    The aim of Artificial Creativity is to gain a better understanding of

    creativity-as-it-isinthecontextofcreativity-as-it-could-be.Inotherwords,

    itisthestudyofcreativityas foundinhumansocietieswithcreativityas it

    maybefoundinartificialsocietiesofagentsthatmayfollowquitedifferent

    socialconventions.Inthisway,thestudyofArtificialCreativityissimilarto

    thestudyArtificialLife; both aresynthetic approachesto understanding a

    complex, and ill-defined behavioural phenomenon, i.e. creativity and life

    respectively.

    The Artificial Creativity approach provides an opportunity for

    researchers to study the emergence of creative behaviour in controllable

    environments,affordinganumberofpossiblestudiesnotpossibleinthereal

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    2 A.AUTHOR,B.AUTHORANDC.AUTHOR

    world. The parameters that control the behaviour of individuals can be

    experimentedwithto study theaffectthat they haveon theemergence of

    socialstructures.Theenvironmentthatthesocietyofagentsissituatedin

    can be adjusted to study the affects that external factors have on the

    creativityofindividualsandsocieties.

    As with Artificial Life, one of the most interesting possibilities of

    Artificial Creativity is to be able to re-run history with different starting

    conditions to find out how products of creative individuals and the

    structures of creative societies might have differed. For example, by re-

    running an Artificial Creativity simulation with different communicationpolicies we can simulate the affect that different communication

    technologiesmighthaveonthe developmentanddisseminationofcreative

    ideas.

    Artificial Creativity is compatible with previous approaches that have

    developedcomputationalmodelsofcreativethinkingbyallowingthemtobe

    deployed within the context of artificial societies as long as they can be

    embedded within agents that conform to the requirements of Artificial

    Creativity.The study ofthebehaviourof creativethinkingwithinartificial

    societiesprovidestheopportunitytodevelopabetterunderstandingofthe

    situatednessofcreativeprocesseswithinsocio-culturalsituations.AsSimon

    (1981)notes,muchofthecomplexityof humanbehaviourmaycomefrom

    thecomplexnatureoftheenvironmentthattheyinteractwith.

    2.Creativity

    Theneedtodefinethenatureofcreativityhashauntedattemptstodevelop

    theoriesoftheprocessesinvolvedincreativethinking.Thedifficultyofthis

    task is apparent from the number of definitions that can be foundin the

    literature:Taylor(1988),forexample,givessome50definitions.Expressed

    in the definitions of creativity are some widely different opinions about

    what it means for a person to be creative. From reading the literature, it

    seemsthatnoagreementmaybereachedondetailsofthecreativeprocess;

    however,thedefinitionsprovidedcanbedividedintotwobroadcategories.

    Firstly,therearedefinitionsofcreativitythatemphasisecreativethinking

    and promote the view that creativity can be studied solely as a mental

    phenomenon.Thesedefinitionshavebeena popularin variousapproaches

    tostudyingcreativitythatdealwithindividuals,forexample,inpsychology,

    cognitive science and artificial intelligence. The models of creativity

    proposedbyKoestler(1964),Newelletal.(1962),andHofstadter(1979)go

    intogreatdetailaboutthecognitiveprocessesinvolvedincreativethinking,

    particularly theprocessesinvolvedinthegenerationofpotentiallycreative

    ideas. Many of the computational models of creativity are either based

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    PAPERTITLE 3

    directlyonthesemodels(e.g.Langleyet al.,1987;Hofstadteret al.,1995)

    orarebasedonsimilarmodelsofcreativethinkingfrompsychology(e.g.

    PartridgeandRowe,1994).

    Definitionsof creativityinthe secondcategoryrecognisethatcreativity

    goesbeyondthegenerationofnovelideasandthatsociety,astheaudience

    of the creative individual, plays an important role in defining what is

    creative.Creativityisthereforedefinedwithastronghonorificsensethatis

    as much the result of an audiences appreciation of a work as it is the

    creatorsproduction.Proponentsofthesedefinitionscontendthatcreativity

    cannotoccurinavacuumandmustbestudiedinthecontextofthesocio-culturalenvironmentofthecreator(Csikszentmihalyi,1999).Thisdefinition

    hasbeenpopularinfieldsthatconsiderthecreativityofmultipleindividuals

    over extended periods of time, for example, in history, sociology and

    anthropology(e.g.Martindale,1990).

    Some researchers have attempted to combine these two views of

    creativity into unified theoretical frameworks. However, the resulting

    frameworks often maintain the distinction between personal and socio-

    cultural notions of creativity, as in Bodens P-creativity and H-creativity

    (Boden,1990)andGardnerssmall-candbig-ccreativity(Gardner,1993).

    2.1.ASYSTEMSVIEWOFCREATIVITY

    WhenCsikszentmihalyidevelopedhissystemsviewofcreativity,heturned

    his attention away from the question What is creativity? and focussed

    upontheissuessurroundingthequestionWhereiscreativity?Importantly,

    Csikszentmihalyi questioned the mentalistic assumption that creative

    processesareonlytobefoundinthemindofthecreativeindividual.Instead

    heproposedthatprocessesessentialtocreativity,whetherpersonalorsocio-

    culturallydefined, are to be found in theinteractions betweenindividuals

    andthesocietythattheyaresituatedwithin.

    Thesystemsviewof creativitywasdevelopedbyCsikszentmihalyias a

    model of the dynamic behaviour of creative systems that include

    interactions between the major components of a creative society

    (Csikszentmihalyi, 1988). Csikszentmihalyi identified three importantcomponents of a creative system; firstly there is the individual, secondly

    thereisacultural,orsymbolic,componentcalledthedomain,andthirdly

    thereis a social, orinteractive,component called the field.A map ofthe

    systemsviewofcreativityispresentedinFigure1.

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    4 A.AUTHOR,B.AUTHORANDC.AUTHOR

    SOCIETY

    Field Individual

    CULTURE

    Domain

    PERSONAL

    BACKGROUND

    Stimulates

    Novelty

    ProducesNovelty

    Transmits

    Information

    Selects

    Novelty

    Figure1:Csikszentmihalyissystemsviewofcreativity(afterCsikszentmihalyi,1999).An individuals role in the systems view is to bring about some

    transformation ofthe knowledge heldin the domain. The fieldis a setof

    social institutions thatselects from thevariations producedby individuals

    thosethatareworthpreserving.Thedomainisarepositoryofknowledgeheldbytheculturethatpreservesideasorformsselectedbythefield.

    Inatypicalcycle,anindividualtakessomeinformationprovidedbythe

    culture and transforms it, if the transformation is deemed valuable by

    society,itwillbeincludedinthedomainofknowledgeheldbytheculture,

    thusprovidinganewstartingpointforthenextcycleoftransformationand

    evaluation.In Csikszentmihalyisview,creativityis nottobe foundinany

    oneoftheseelements,butintheinteractionsbetweenthem.

    2.1.1.LiusDualGenerate-and-TestModelofCreativity

    Recognisingtheneedforaunifiedmodelofcreativityindesigncomputing,

    Liu(2000)presentedasynthesisofthepersonalandsocio-culturalviewsof

    creativityinasinglemodel.Liurealisedthattheexistingmodelsofpersonalcreativity complemented the socio-cultural models by providing details

    abouttheinnerworkingsofthecreativeindividualmissingfromthemodels

    ofthelargercreativesystem.

    Liuproposeda dualgenerate-and-testmodelofcreativityasasynthesis

    ofSimonetalsmodelofcreativethinkingandCsikszentmihalyissystems

    view. Asits name suggests, thedual generate-and-test model of creativity

    encapsulatestwo generate-and-testloops:oneat theleveloftheindividual

    and the other at the level of society. The generate-and-test loop at the

    individual level, illustrated in Figure 2(a), provides a model of creative

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    PAPERTITLE 5

    thinking, incorporatingproblemfinding, solutiongeneration andcreativity

    evaluation.Thesocio-culturalgenerate-and-testloopmodelstheinteractions

    among the elements of Csikszentmihalyis systems view of creativity, as

    illustrated in Figure 2(b). In particular, it captures the role that the field

    playsasasocio-culturalcreativitytest.Thecombineddualgenerate-and-test

    modelofcreativityisillustratedinFigure2(c).

    GenerateProblem

    Finding

    no

    yes

    yes

    no

    Field

    Individual

    Domain

    Personalcreativesolution

    generationandrecognition

    Social-culturalrecognitionofcreativeideasbyagroupofauthorisedpeople

    Sourceof

    initialdataand

    knowledgein

    thedomain

    Creativity

    Test

    GenerateProblem

    Finding

    no

    Individual

    Personalgenerate-and-test

    Test

    Domain

    Knowledge

    Creative

    Product

    yes

    no

    yesField

    Individual

    Domain

    Socio-culturaltest

    Problems&

    SolutionsSocio-culturalgenerate

    (a)

    (b)

    (c)

    Figure2:Liu'sDualGenerate-and-TestModelofCreativeDesign:(a)thepersonalgenerate-and-testmodel,(b)thesocio-culturalgenerate-and-testmodel,(c)thecombineddual

    generate-and-testmodel.

    Lius model unifies Simon et als and Csikszentmihalyis models of

    creativity to form a computational model of creativity that shows how

    personalandsocio-culturalviewsofcreativitycanbemodelledinasingle

    system.ComparedtoBodensmodelofcreativity,thedualgenerate-and-test

    model of creativity models both the P-creativity and H-creativity of

    individuals using the generate-and-test loops at different levels.Using the

    languageofGardnerwe may say thatwhatdistinguishessmall-c creativity

    frombig-ccreativityisthatbig-ccreativityaffectschangestothedomain

    whereassmall-ccreativitydoesnot.Lius dual generate-and-test model shows that it is possible to cast

    Csikszentmihalyis systems model in computational terms and thereby

    providesuswithausefulbasisforaframeworkfordevelopingmodelsof

    Artificial Creativity. Before developing Lius model further, we will

    examinetherequirementsofacomputationalmodelofArtificialCreativity.

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    6 A.AUTHOR,B.AUTHORANDC.AUTHOR

    3.ArtificialCreativity

    The Artificial Creativity approach that we propose here is based on

    Langtons approach todevelopingcomputational modelsof ArtificialLife

    (Langton, 1989). The essential requirements of a computational model of

    ArtificialCreativityare:

    Themodelcontainsasocietyofagentssituatedinaculturalenvironment.

    Thereisnoagentthatcandirectthebehaviourofalloftheotheragents.

    Therearenorulesthatdictateglobalbehaviour.

    Agentsinteractwithotheragentstoexchangeartefactsandevaluations.

    Agentsinteractwiththeenvironmenttoaccessculturalsymbols.

    Agentsevaluatethecreativityofartefactsandotheragents.

    Many of the requirements of a computational model of Artificial

    Creativity are similar to the requirements of a computational model of

    Artificial Life. Although some of the details are different, both types of

    modelsconsistofa populationofagents,andbothrequirethatthereareno

    rulesoragentsthatcandictateglobalbehaviour.

    AnadditionalrequirementofArtificialCreativityagentsnotfoundinthe

    requirementsofArtificialLifeisthattheagentsinanArtificialCreativitymodelmustbeabletomakeindependentvaluejudgementsandadapttheir

    behaviour accordingly.Morespecifically,agentsinan ArtificialCreativity

    systemmustbe abletomakeevaluativejudgementsaboutthe creativityof

    agentsandproductsinordertoimplementthepersonalandsocio-cultural

    creativitytestsfoundinLiusmodel.

    Toillustratetheapproach,considerhowonewouldmodelasocietyof

    artists.First,wewoulddefinearepertoireofbehavioursfordifferentartistic

    agentsandcreatelotsoftheseagents.Wewouldthenstartasimulationrun

    by specifying some initial social configuration of the agents within a

    simulatedculturalenvironment.Fromthispoint onwardsthe behaviour of

    the system would depend entirely on the interactions between different

    agents and the interactions between the agents and their culturalenvironment.Importantly,therewouldbenosingleagentthatcouldenforce

    a definition of creativity by controlling the behaviour of all of the other

    agents. In addition, there would be no rules in the agents or in the

    environmentthatwoulddefineaglobaldefinitionofcreativity.Thenotions

    ofwhomandwhatarecreativeheldbythesocietywouldemergefromthe

    multiplenotionsofcreativityheldbytheindividualagents.

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    PAPERTITLE 7

    3.1. THEIMPORTANCEOFEMERGENCE

    The requirements of Artificial Creativity are designed to model the

    emergenceofphenomenainsocietiesofagentsconsistentwithcreativityin

    human society. Emergence is an important feature of Artificial Creativity

    systems,wherephenomenaatacertainlevelarisefrominteractionsatlower

    levels.

    Inphysicalsystems,temperatureandpressureareexamplesofemergent

    phenomena. Temperature and pressure are emergent properties of large

    ensemblesof molecules andare dueto interactionsat themolecularlevel.Anindividualmoleculepossessesneithertemperaturenorpressure;theyare

    propertiesthatonlyemergewhenmany moleculesarebrought together.In

    Artificial Life, the stable patterns in cellular automata, and the flocking

    behaviourofsimulatedbirdsareexamplesofemergentphenomena.

    InArtificialCreativity,thesocio-culturalevaluationsofwhomandwhat

    are creative are emergent phenomena; no individual can dictate the

    collectiveevaluationsofwhomandwhatarecreative,theycanonlytryto

    influence other individuals by exposing them to their products and their

    personal evaluations. The emergence of macro-level creativity from the

    interactionsofindividualsatthemicro-levelisillustratedinFigure3.

    Figure3:Abehaviour-basedapproachtothestudyemergenceofcreativebehaviouratthe

    levelofsocietybymodellingthebehaviourofindividuals(afterLangton,1989).

    In Bodens terms we might be tempted to say that H-creativity is

    emergent whereas P-creativityis notbecausetheprocessesthatimplementP-creativity test are fixed. However, in the Artificial Creativity system

    describedlatertheinteractionbetweenagentsandthecontinuallearningof

    the agents through exposure to new artefacts mean that what an agent

    considerstobeP-creativeisanemergentpropertyofthewholesystem.An

    individualembeddedwithinanArtificialCreativitysystemisaffectedbyits

    socio-cultural context such that it will not produce the same P-creative

    productsas itwouldin isolation.Hence,bothH-creativityandP-creativity

    mustbeconsideredemergentpropertiesofcreativesystems.

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    8 A.AUTHOR,B.AUTHORANDC.AUTHOR

    4. AFrameworkforArtificialCreativity

    Thissectionpresentsaframeworkfordevelopingcomputationalmodelsof

    Artificial Creativity. The framework is presented by adapting Lius dual

    generate-and-test model to meet the requirements of Artificial Creativity

    listedabove.

    4.1. ADAPTINGLIUSMODELTOARTIFICIALCREATIVITY

    A critical aspect of Lius model that must be addressed to developcomputational models ofartificial creativityis the definition of thesocio-

    cultural creativity test. A literal implementation of Lius model would

    produce a separate process that would model the socio-cultural creativity

    test.This is a viable solutionformodelling some aspects ofcreativity,as

    demonstratedbythecomputationalmodeldevelopedbyGaboratostudythe

    memeticspreadof innovationsthrough asimulatedcultureGabora(1997).

    Colton (2000) applied a similar socio-culturalcreativity test to assess the

    increaseincreativityduetotheco-operationofagentssearchingaspaceof

    mathematical possibilities using different search heuristics. However,

    implementing a single function, or agent, that model a socio-cultural

    creativitytestwouldviolateoneoftherequirementsforArtificialCreativity

    outlinedpreviously,i.e.thatnoruleoragentshoulddirectglobalbehaviour.Liudoesnotgointodetailsaboutthedefinitionofthisfunctionbutit

    appears that he considers this function to be outside the scope of

    computationalmodelsandsomethingthatcanonlybeimplementedbysome

    form of interaction with human society. Many computational models

    developed reinforce this view by concentrating on the constrained

    generationofnovelideasintheircomputationalmodelsandrelyingonusers

    toevaluatethecreativeworthofideas.Forexample,seeClancey(1997)for

    adiscussionofthesocialsituatednessofHaroldCohensAARON.

    To computationally model the behaviour of creative societies, it is

    necessary to define a socio-cultural creativity test without violating the

    requirementsofArtificialCreativity.Thekeytosolvingthisproblemisto

    realisethatthepersonalcreativitytestinsideeachindividualcanbeusedto

    developasocio-culturaltestforcreativity.Thesocio-culturalcreativitytest

    can be modelled by permitting the communication of artefacts and

    evaluations of personal creativity between individuals. An illustration of

    twoindividualscommunicatingcreativityevaluationsisillustratedinFigure

    4.

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    PAPERTITLE 9

    IndividualB

    IndividualA

    Problem

    Finding

    Creativity

    TestGenerate

    Creativity

    TestGenerateProblem

    Finding

    no

    no

    yes

    To

    Domainyes

    yes

    Figure4:Thecommunicationofevaluationsbetweenindividualsanditsintegrationintothe

    individualgenerate-and-testcycle.

    In the interaction illustrated in Figure 4, Agent A communicates an

    artefactthatitconsiderstobecreative,i.e.thatpassesitpersonalcreativity

    test, to Agent B. Agent B evaluates the artefact according to its own

    personal creativity test and sendsits evaluation back to Agent A. In thisway,Agent Bcan affectthe generationof future artefactsbyAgentA by

    rewardingAgentAwhenitgeneratesartefactsthatAgentBconsiderstobe

    creative. More subtly, Agent A can affect the personal creativity test of

    AgentBbyexposingittoartefactsthatAgentAconsiderstobecreative,

    becausetheevaluationofcreativityinvolvesanevaluationofnovelty,Agent

    AaffectsachangeinAgentBsnotionofcreativitybyreducingthenovelty

    of the type of artefacts that it communicates. By exposing Agent B to

    artefactsthatAgentAconsiderstobecreative,becausetheyarenoveland

    yetunderstandable,itcanaltertheevaluationofcreativitymadebyAgent

    B.

    Agent-centric evaluations of creativity permit the emergence of socio-

    cultural definitions of creativity as the collective function of many

    individualevaluations.Withoutagent-centricevaluationsofinterestingness

    thecollectionofagentswouldsimplyrepresentparallelsearchesofthesame

    designspace.Toimplementthesocio-culturalcreativitytestasacollective

    functionofindividualcreativitytestsa communicationpolicyisneeded.A

    simplecommunicationpolicywouldbeforagentstocommunicateaproduct

    whentheirevaluationofthatproductisgreaterthansomefixedthreshold.

    More complex communication policies might incorporate more strategic

    knowledgeaboutwhentocommunicateandwhotocommunicatewith.

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    10 A.AUTHOR,B.AUTHORANDC.AUTHOR

    To complete the implementation of the field as a collection of

    individuals, the individuals must be given the ability to interact with the

    domain according to some domain interaction policy. A simple domain

    interactionpolicywouldfollowthecommunicationpolicyaboveandallow

    agents to addproductsof thegenerative process if thepersonalcreativity

    evaluationisgreaterthanadomaininteractionthreshold.Thisapproachis

    illustratedinFigure4.However,toensuresomelevelofsocialagreement

    before the addition of products to the domain, a slightly more complex

    domain interaction policy ensures thatno individual is allowed to submit

    theirownworktothedomain.Thus,atleastoneotheragentmustfindanindividualsworkcreativebeforeitisenteredintothedomain.

    Makingtheseamendmentsto Lius dualgenerate-and-testresultsin the

    modelofsocio-culturalcreativityillustratedinFigure5.

    Field Domain

    Individual

    Individual Individual

    Individual

    Individual

    Individual

    Individual Individual

    Figure5:TheArtificialCreativitymodelofsocio-culturalcreativity.

    5. TheDigitalClockworkMuseProject

    In The Clockwork Muse Martindale (1990) presented an extensive

    investigation into the role that an individuals search for noveltyplays inliterature,music,visualartsandarchitecture.He concludedthatthesearch

    fornoveltyexertsasignificantforceonthedevelopmentofstyles.

    Martindale illustrated the influence of the search for novelty by

    individuals in a thought experiment where he introduced The Law of

    Novelty.TheLawofNoveltyforbidstherepetitionofwordordeedand

    punishesoffendersbyostracisingthem.MartindalearguedthatTheLawof

    Noveltywasmerelyamagnificationoftherealityincreativefields.

    Someof theconsequencesof thesearchfornoveltyare thatindividuals

    thatdonotinnovateappropriatelywillbeignoredinthelongrunandthat

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    PAPERTITLE 11

    the complexity of any one style will increase over time to support the

    increasing need for novelty. In this section, we present a computational

    model of the Law of Novelty developed using our Artificial Creativity

    approachusingcuriousdesignagentsthatsearchfornovelty(Saunders&

    Gero,2001b).

    Ourmodelconsistsof multiplecuriousdesign agentswithina single

    field conducting searches for interesting and potentially creative genetic

    artworks.Eachagentisequippedwithanevolutionaryartsystemtoallow

    itto generategeneticartworksandcancommunicatewithoneotheragent,

    chosenatrandom,oneachtimestep.Individualsthatproduceartworksthatare considered creative by other agents are rewarded with creativity

    credit.

    5.1. THEINDIVIDUAL:ACURIOUSDESIGNAGENT

    This subsection describes the important components of a curious design

    agent and the interactive evolutionary system that it interacts with. The

    agentsintheDigitalClockworkMuseProjecthavebeendevelopedusinga

    model of curiosity that wehaveappliedto several domainscan befound

    elsewhere (Gero and Saunders, 2000; Saunders and Gero, 2001a; 2001b;

    2001c).Themodelofcuriosityprovidestheessentialabilityforagentsto

    evaluate thecreativity of artefacts andtakeappropriate action, i.e.evolvenew artefacts, communicate with otherindividuals in the field,or add an

    artefacttothedomain.

    5.1.1. InteractiveEvolution

    Every agent in The Digital Clockwork Muse uses an interactive

    evolutionaryartsystem,similartotheonesdevisedbyDawkins,Sims,Todd

    and Latham, and others (Dawkins, 1987; Sims, 1991; Todd and Latham,

    1992) to generate genetic artworks. Interactive evolutionary art systems

    useastandardevolutionarysystem,e.g.ageneticalgorithm,toevolvesmall

    populationsofartworksthatarepresentedtoahumanuserforevaluation.In

    our system, agents take the place of human users and interact with the

    evolutionaryartsystemstosearchfornovelgeneticartworks.Theflowofinformationbetweenanagentanditsevolutionaryartsystemisillustratedin

    Figure6.

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    12 A.AUTHOR,B.AUTHORANDC.AUTHOR

    IndividualB

    Creativity

    TestGenerateProblem

    Finding

    no yes

    img img img

    EvolutionarySystem

    img img img

    img img img

    SelectsInteresting

    Images

    EvolvesPopulation

    ofImages

    Figure6:Acuriousdesignagentandaninteractiveevolutionaryartsystem.

    5.1.2. GeneticArtworksKarlSimsisbestknownforhisworkdevelopingoneofthefirstinteractive

    evolutionaryartsystemsforcomplextwo-dimensionalbitmapimages(Sims,

    1991). Using a process similar to Genetic Programming, Sims devised an

    evolutionary art system that produced artworks by evolving symbolic

    functiontrees.

    An example genetic artwork of the type evolved by the agents in this

    project is shown in Figure 3. This genetic artwork was evolved over the

    InternetaspartoftheInternationalInteractiveGeneticArt(IIGA)project

    (WitbrockandReilly,1999). Theevolutionarysystemsusedinthisproject

    weredevelopedusingsourcecodefromtheIIGAproject.

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    PAPERTITLE 13

    Figure3:Anexampleofageneticartworkinteractivelyevolvedbyahumanuser.(Fromthe

    archiveofevolvedgeneticartworksinInteractiveGeneticArtIII.)

    5.1.3. Sensing

    A 32x32-pixel image of each genetic artwork is analysed by a curiousdesign agent to determine its novelty. Although this is a low-resolution

    imageitisstilllargeenoughtoallowcomplexartworkstobeevolved.To

    sense the image, a relatively simple combination of a Laplacian edge-

    detectorandafixedintensitythresholdfunctionwereusedtotransforma

    geneticartworkintoabinaryimage,asshowninFigure7.

    (a) (b)

    Figure7:Theimageprocessingappliedtogeneticartworkstoextracttheedgestructureof

    theimages,(a)theoriginalimage,and(b)thebinaryimageproducedbytheimageprocessing

    tofindthemostprominentedges.

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    14 A.AUTHOR,B.AUTHORANDC.AUTHOR

    5.1.4. Novelty

    Each agent is equipped with a neural network to learn the categories of

    images as it explores the space of possible genetic artworks. A self-

    organising map, or SOM, (Kohonen, 1995) is used to categorise each

    artworkthatanagentencountersintoacategoryrepresentedbyoneofthe

    networksneurons.Ateachpresentationofanartworktheprocessedbinary

    image is converted into a vector consisting of 1024 values. As an agent

    exploresthespaceofpossibilitiesitlearnsamapoftypicalartworksforthe

    region of the genetic art space it currently occupies. By comparing new

    artworks against this map, the agent can detect novel, and potentiallyinteresting,artworks.

    Themapthattheneuralnetworkproducesprovidesaformofshort-term

    memory for the agent to compare new artworks with previously created

    ones.Thelargerthenetwork,themoreneuronstheagenthas,andthemore

    categoriesofartworksitcanrememberandrecallforcomparison.

    Figure 8 shows the neighbourhoods thathave formed for similar input

    patterns,e.g.aroundE2andA6,aswellasthemixingofthesepatternsin

    theintermediateareas,e.g.aroundD4.Themixingofrepresentationsinthis

    wayprovidesanagentwiththeabilitytogeneralisefrompastexperiences

    andhencepredictaspectsofunseenartefacts.Thisisanimportantability

    forcuriousdesignagentsbecauseitallowsthemtodeterminethenoveltyof

    newartefactswithoutsamplingallofthedesignspace.

    A B C D E F

    1

    2

    3

    4

    5

    6

    Figure8:Theprototypesrepresentedbythe36neuronsofaself-organisingmaphavingjust

    categorisedtheinputshowninFigure4batlocationE2.

    Novelty(N)iscalculatedasthecategorisationerrorofanagentsSOM

    asitattemptstoidentifyasuitablecategoryforanartwork.Noveltyvalues,

    i.e.thevaluesofoutputbythebestmatchingneuronoftheneuralnetwork

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    PAPERTITLE 15

    dependonthesizeof image,inthiscasethesevaluesareintherangeN=0

    and N=32, with N=0 being an exact match and N=32 being a complete

    mismatch. Effectively this measures the distance of the closest category

    prototypetotheinputpattern.

    TheEuclideandistancebetweentheclosestcategoryprototypeandanew

    inputpatternisarathercrudemeasureofnovelty,andmoresophisticated

    measureshavebeendevelopedbyseveralresearchersincludingtheauthors

    (Kohonen, 1993; Marsland et al., 2000; Saunders and Gero, 2001c),

    however, for the purposes of this demonstration system the measure of

    novelty provided by the categorisation error is sufficient andcomputationallyinexpensive.

    Novelty is used as the sole criterion to evaluate evolved artworks for

    interestingness.Assuchwedefinetheinterestingnessofanartworkbased

    on the degree to which it could not have been predicted from previous

    experience. Thisis similar to BodensnotionofP-novelty(Boden,1990).

    Ourdefinition of interestingnessbasedonnoveltyalonelackstheexplicit

    requirement for usefulness needed to model P-creativity as defined by

    Boden but,we argue that because interesting artworks are actionable,i.e.

    theypromotecuriousaction,theusefulnessofanartworkisitspotentialto

    leadtootherinterestingartworksandistherefore,withintheconfinesofthis

    simplesystem,relatedtoitsnovelty.

    5.1.5. Interestingness

    Interest in an artwork is calculated using an approximationto the Wundt

    curve, a well-known arousal response curve developed from studies of

    animals and humans to exposed to arousal producing stimuli, including

    novelty(Berlyne,1971).TheWundtcurveissketchedinFigure9.Berlyne

    (1971) refers to the Wundt curve as a hedonic function, to indicate its

    relationship to the pleasure/pain response that is often associated with

    arousingstimuli.

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    16 A.AUTHOR,B.AUTHORANDC.AUTHOR

    HEDO

    NIC

    VALUE

    NOVELTYNx

    Hx

    Reward

    Punish

    0

    1

    -1

    n1 n2

    Figure9.Thehedonicfunctionusedtocalculateinterest.Thehedonicfunctionisshownasa

    solidline,therewardandpunishmentcurvesareshowndashed.

    In our model the hedonic function is calculated as the sum of two

    sigmoidal functions whereas the Wundt curve is calculatedas the sum of

    cumulative-Gaussianfunctions. Themost important feature ofthe hedonic

    function used in this research that it shares in common with the Wundt

    curveis that it is the sum of two non-linear functions. Ineither case the

    functionsaresummedtoproduceaninvertedUshapedcurve,assketched

    in Figure 9. The sigmoidal function labelled Reward represents the

    intrinsicrewardgiventotheagentforfindinganarousal-inducingstimulus

    over a fairly lowthreshold, n1.The second function, labelled Punish,is

    the amount of punishment that the agent receives for finding an arousal-

    inducingstimulusoverahigherthreshold,n2.Byalteringthethresholdsfor

    the reward and punishment sigmoid curves this peak can be positioned

    anywherealongthenoveltyaxis.

    The agents in the Digital Clockwork Muse use the above hedonic

    function to calculate the level of interest that they have in a particular

    artworkbaseduponthenoveltydetectedbytheself-organisingmap.Figure9illustratestheuseof thehedoniccurvewithanexamplenoveltyvalueNx

    thatismappedtoitscorrespondinghedonicvalueHx.

    5.1.6. Curiosity

    Throughacombinationoftheneuralnetworkandthehedonicfunctionthe

    agentsdisplayaformofcuriousbehaviour.Givenasetofnewartworks

    an agent will favour those that are imperfectly represented by the self-

    organisingmap,indicatingtheneedforsomelearning,butarenotsonovel

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    PAPERTITLE 17

    as to fall beyond the peak of the hedonic function. Thus the agent is

    motivated to choose artworks it has a good chance of improving its

    representation of by favouring similar-yet-different artworks at each time

    step (Berlyne, 1971). In other words, the agent shows little interest in

    artworks that are either too similar or too different to its previous

    experiences(Schmidhuber,1991)

    Anagentsinterestinanartworkdeterminestheartworksactionability.

    If an artwork is the most interesting at a given moment without being

    interestingenoughtobeconsideredcreativethentheartworkisselectedas

    thestartingpointforfurthersearchbutnotsenttoanyotheragents.

    5.2. THEFIELD:ACOMMUNITYOFINTEREST

    Todefine a fieldin anArtificial Creativitysystemwe need todefine the

    communication mechanisms and policies used by agents to exchange

    artworks and evaluations. For this project we have chosen to use the

    simplestimplementationspossible.

    5.2.1. Communication

    Iftheinterestingnessofanartworkbreachesathresholdvaluethatmarksthe

    lowerboundoftherangeofpotentiallycreativeartworksthentheartworkis

    senttootheragentsforpeerreview.Artworksareexchangedasmessagesthatencodethesymbolicdescriptions

    of the artworks. Receiving agents must then express the genetic

    representationtorecovertheartworkandthenevaluateit.Havingexpressed

    areceivedartworkanagentevaluatesitaccordingto itspersonalcreativity

    testbasedonitsownexperiences.Theexperiencesofareceivingagentare

    likely to be different than those of the sender and this can lead to very

    different evaluationsof thesame artwork.An artwork thatwasinteresting

    foritscreatormaybeboringtoasecondagentbecauseitistoofamiliaror

    uninterestingtoathirdbecauseitisnotfamiliarenough.

    Anagentmayfindareceivedartworkmoreinterestingthanitsowncurrent

    artworks,inwhichcaseitcanusethereceivedartworkasthestartingpoint

    foranewsearchofthegeneticartspace.An advantage of passing the genetic representations of artworks between

    agents,ratherthantheartworksthemselves,isthatifareceivingagentfinds

    an artwork interesting it can usethegenetic representationto evolvenew

    artworks without having to reverse engineer an artwork first. This is a

    computationally efficient approach to distributing artworksbut it removes

    thepossibilityofmemeticevolutionofartworksthroughtheintroductionof

    errorsduringthe imitationprocess(Dawkins, 1976).Tosafeguard against

    plagiarismandtherebystopapopularartworkbeingcopiedbyallmembers

    of a population unaltered, an agent is not allowed to pass on a received

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    18 A.AUTHOR,B.AUTHORANDC.AUTHOR

    artwork as its own in the same cycle; it must perform at least one

    evolutionarygenerationfirst.

    Before using an artwork received from elsewhere an agent must pay the

    creatoroftheinterestingartworksomecredit,proportionaltotheinterestthe

    receiving agent has in the artwork. The amount of credit accumulated

    throughoutalifetimeisusedtoassesshowcreativeaparticularindividual

    is.

    5.3. THEDOMAIN:AREPOSITORYFORCREATIVEARTWORKS

    Adomainismaintainedbythecollectiveactionsofagentsinitsassociated

    field. We have implemented the minimal domain interaction policy that

    ensuressomeformofsocialagreementwithinafieldbeforeanartworkcan

    beaddedtoadomain.Agentscannotaddtheirownartworkstothedomain;

    they can only add artworks that they receive from others. Toqualifyfor

    addition to the domain an artwork must be of particularly high

    interestingnessforthereceivingagent,mostlikelyhigherthanthatrequired

    for an artwork to be considered worthy of communicating to another

    memberof isfield.If so, the artworkis addedtothe domainwith alabel

    indicatingtheagentthatcreatedit.

    Futuregenerationsofgeneticartistsbegintheirsearchwithartworksthat

    havebeenaddedtothedomain,however,thedynamicnatureofthesocio-cultural evaluation process means that artworks that were considered

    creativearelikelytobe nolongerconsideredcreativebecausetheyaretoo

    familiarto thefield.Therefore,thedomaindoesnotprovideinstantaccess

    tocreativeworks,butratherastoreoffamiliarstartingpointsfromwhich

    newcreativeartworkscanbeproduced.Therealadvantageofstartingwith

    artworks stored in the domain is that they are already familiar to other

    membersofthefield.Theresultofashortsearchfornovelartworksstarting

    withexamplesfromthedomainislikelytobenewartworksthataresimilar-

    yet-differentwithrespecttothedomain,makingthemidealcandidatesfor

    beingcreative.

    ResearchersofArtificialCreativitycanalsousetherecordskeptinthe

    domain as a means to trace the development of artistic stylesconsideredcreativeovertime.

    6. ExperimentsinArtificialCreativity

    The following experiments were conducted with the aim of confirming

    Martindales predictionsfor Artificial Creative systemsand to investigate

    otherinterestingemergentbehaviour.

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    PAPERTITLE 19

    6.1. THELAWOFNOVELTY

    Weinvestigatedthe effectsof thesearchfor novelty, byproducingagents

    withdifferenthedonicfunctions.Theaimwastoshowthatagentsarenot

    recognised as creative when they fail to innovateinappropriately. Agents

    can innovateinappropriately either byproducing boringimagesthat are

    too similar to images previously experienced by other agents, or by

    producing radical images that are too different for other agents to

    appreciate.

    We have simulated both types of inappropriate innovation in a singlesimulation.Forthisexperimentwecreatedagroupofagentsmostofwhom,

    agents0-9,sharedthesamehedonicfunction,i.e.thesamepreferencefor

    average novelty (N=11). Two of the agents have quite different novelty

    preferences. One, agent 10, has a preference for low amounts of novelty

    (N=3)andtheother,agent11,hasapreferenceforhighamountsofnovelty

    (N=19).Agentswithalowernoveltypreferencetendtoinnovateataslower

    rate than those with a higher hedonic preference. The results of the

    simulationarepresentedinTable1.

    TABLE1.Theattributedcreativityforagroupofagentswithdifferentpreferencesfor

    novelty.

    Agent

    ID

    Preferred

    Novelty

    Attributed

    Creativity

    0 N=11 5.43

    1 N=11 4.49

    2 N=11 4.50

    3 N=11 3.60

    4 N=11 4.48

    5 N=11 1.82

    6 N=11 6.32

    7 N=11 8.93

    8 N=11 10.72

    9 N=11 5.39

    10 N=3 0.0

    11 N=19 0.0

    Theresultsshowtheagentswiththesamepreferencefornoveltytobe

    somewhat creative according to their peers, with an average attributed

    creativity of 5.57. However, neither agent 10 nor agent 11 received any

    credit for their artworks.Consequently noneof the artworksproducedby

    theseagentsweresavedinthedomainforfuturegenerations.Whenthese

    agentsexpirednothingremainedinthesystemoftheirefforts.

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    20 A.AUTHOR,B.AUTHORANDC.AUTHOR

    The results show that while an agent must innovate to be considered

    creative, it must do so at a pace that matches other agents to achieve

    recognition. The agent with a preference for high levels of novelty and

    hence rapid innovation was justas unsuccessful in gainingrecognition as

    theagentwithalownoveltythresholdthatinnovatedtooslowly.

    6.2. THEEMERGENCEOFCLIQUES

    Wehavealsoinvestigatedthebehaviourofgroupsof agentswithdifferent

    hedonicfunctions.Todothiswecreatedagroupof10agents,halfofthemhadahedonicfunctionthatfavourednoveltyN=6andtheotherfiveagents

    favoured novelty values close to N=15. Figure 9 shows the payments of

    creativity credit between the agents in recognition of interesting artworks

    sentbytheagents.

    2 8 2

    21 3 4 5 6 7 8 9

    1

    2 1 1 3

    4 5 2 5

    2 23 3

    1 16 3 5

    3 4 5 1

    3 5 1 4

    4 3 2 4

    1 4 4 4

    0

    0

    1

    2

    3

    4

    56

    7

    8

    9

    Sender

    Rec

    eiver

    Figure9:Amatrixshowingthetotalnumberofmessagescarryingcreditforbeingcreative

    betweentheagentsofthesimulation.

    Two areas of frequent communication can be seen in the matrix of

    payment messages shown inFigure 9. The agents with the same hedonic

    functionfrequentlysendcreditforinterestingartworksamongstthemselves

    butrarelysendthemtoagentswithadifferenthedonicfunction.Therearea

    largenumberofcreditmessagesbetweenagents0-4andagents5-9,butonly

    onepaymentbetweenthetwogroupsagent4creditsagent5forasingle

    interestingartwork.

    The result of putting collections of agents with different hedonic

    functionsinthesamegroupappearstobetheformationofcliques:groups

    ofagentsthatcommunicatecreditfrequentlyamongstthemselvesbutrarely

    acknowledgethecreativityofagentsoutsidetheclique.Asaconsequenceof

    the lack of communication between the groups the style of artworks

    producedbythetwocliquesalsoremainsdistinct.

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    PAPERTITLE 21

    Communicationbetweencliquesisrarebutitisanimportantaspectof

    creativesocialbehaviour.Communicationbetweencliquesoccurswhentwo

    individuals in the different cliques explore design subspaces that are

    perceptuallysimilar.Eachoftheindividualsisthenabletoappreciatethe

    others work because they have constructed appropriate perceptual

    categories. The transfer of artworksfroma sourceto a destinationclique

    will introducenew variablesinto thecreativeprocessesof thedestination

    clique,thetwocliquescanthenexploreindifferentdirections,justastwo

    individuals do when they share artworks. Cliques can therefore act as

    super-artists,exploringadesignspaceasacollectiveandcommunicatinginterestingartworksbetweencliques.

    Figure10is ascreenshotoftherunningsimulationthathasformedtwo

    cliques. To help visualise the emergent cliques, the distances between

    agentsare shortenedforagentsthatcommunicatefrequently.Thedifferent

    stylesofthetwogroupscanalsobeseen,withagents0-4producingsmooth

    radialimageswithlowafractaldimension(~1.4)andagents5-9producing

    fracturedimageswith clearlydefinededgesandahigherfractaldimension

    (~1.7).

    Figure10:Ascreenshotofthesimulationclearlyshowingthetwocliques.Thesquares

    representagents.Theimagesshowthecurrentlyselectedgeneticartworkforeachagent.The

    numberaboveeachsquareshowstheagentsattributedcreativity.Thedarklinesbetween

    agentsindicatethecommunicationofcredit.

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    22 A.AUTHOR,B.AUTHORANDC.AUTHOR

    7. FutureResearch

    ArtificialCreativitysimulationspermittheinvestigationofmanyinteresting

    aspectsofcreativityincomputationalmodels.Thissubsectionwillexplore

    someoftheseaspectsandhowcomputationalmodelscanbedevelopedto

    gainabetterunderstandingofthem.

    7.1. COMPUTATIONALLYSTUDYINGHISTORICALCREATIVITY

    One of the most interesting possibilities supported by the currentlyimplemented system is the possibility to study H-creativity in artificial

    societies.Runningsimilarsimulationsto thosedocumentedaboveforlong

    periodsoftimeprovidesanopportunitytostudytherevisionofcreativity

    over many generations. As noted by Boden (1990) the attribution of H-

    creativityto individuals andtheir productsis oftenrevisedover time. We

    canexpecttofindsimilarrevisionsinArtificialCreativitysimulations:we

    would expect to observesimilarre-evaluations,e.g.the recognitionof the

    creativityofindividualsbylatergenerationsthatwasnotrecognisedbytheir

    peers.

    7.2. THESITUATEDNESSOFARTIFICIALCREATIVITY

    Thestudyofsituatednesshasbecomeapopulartopicofresearchinrecent

    years in design computing (Gero& Reffat, 1997; Gero, 1998) anddesign

    cognition(Suwa&Tversky,1997;Suwa,GeroandPurcell,1999).Artificial

    Creativityprovidesnewopportunitiestostudysituatednesscomputationally.

    Importantly, the computational modelling of the individual, field and

    domainina singlesystempermitsthestudyofboththeinteractivenotions

    of situatedness, and the cultural notions of situatedness. Interactive

    situatedness has been studied computationally before, e.g. in models of

    reflection-in-action(GeroandSaunders,2000).

    The cultural situatedness of individuals is crucial to design as a

    profession concerned with the socio-cultural change, yet it has been

    neglectedincomputationalstudiesbecauseofthe difficultiesof situatinga

    computational model in real world cultures. Some examples of programsthathaveinteractedwithcreativefieldsintherealworldareprogramsthat

    havebeeninvolvedintheinventionofnewproducts,mostnotablediscovery

    systemslikeEURISKO(Boden,1990).However,allofthesesystemshave

    requiredhumaninterventionwhentomediateinteractionswiththerelevant

    fields and domains. Artificial Creativity allows us to study socio-cultural

    situatedness as an emergent property of communicating agents that are

    individuallysituatedintheirhistoryofexperiences.

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    PAPERTITLE 23

    7.3. CREATIVEINDIVIDUALS

    ArtificialCreativityprovidesuswithopportunitytostudythecharacteristics

    ofcreativeindividuals.Severalimportantcharacteristicsof eachindividual

    can be identified and adjusted by altering parameters. We have already

    investigatedthebehaviourofagentswithdifferenthedonicfunctionsandwe

    could extend these studies by adjusting different parameters or using

    functions other than the Wundt curve. Other parameters that we could

    experiment with include those that control the learning and the sensors,

    effectors and interaction policies ofagents.For example,by changingtheparametersthatcontrolthesizeoftheSOMscurrentlyusedintheagentswe

    can effectively experiment with individuals with longer and shorter

    memories.

    7.3.1. TheLifecycleofCreativeIndividuals

    Thereissomedebateoverwhethercreativeindividualsdotheirbestwork

    whentheyareyoungorwhethertheycontinuetobejustascreativeinlater

    life (Simonton). The study of Artificial Creativity provides us with

    opportunity to study the lifecycles of creative individuals and the

    mechanismsbywhichthecreativepotentialofindividuals,withrespectto

    society, increases or decreases as the agent develops. Adjusting the

    parameters discussed above we can experiment with agents that havedifferent abilities and observe how their creative potential changes over

    theirlifespan.Forexample,byusinganeuralnetworkthatlearnsquickest

    whenyoungwecanstudyhowthecreativityofanagentisaffectedasthe

    abilitytolearnistradedoffagainsttheknowledgegained.

    7.3.2. TheEvolutionofCreativeIndividuals

    18th Century theories of creativity suggested that it was an inherited

    characteristic based on the observation that creative ability often ran in

    families,implyingthatthegeneticmakeupofanindividualdeterminedtheir

    creative ability. These theories have been superseded by more balanced

    explanations of the roles of nature and nurture in the development of

    creativeindividuals,butthisdoesnotmeanthatwecannotinvestigatetheevolutionof creativeindividualsthroughtheacquisitionofgenetictraitsin

    Artificial Creativity simulations. To do so, we simply need to define a

    genotypethat determines the values for the characteristics of individuals,

    e.g.sizeandtypeofneuralnetwork,andselectindividualsforreproduction

    based on their creative status. Interesting observations would include

    whether or notthe genetic make-up ofcreativeindividualsconvergeupon

    certainparametersoverseveralruns.Ifconvergencesofthissortcouldbe

    found then we should be able to identify something like creative

    personalitytraitsinindividuals.

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    24 A.AUTHOR,B.AUTHORANDC.AUTHOR

    7.3.3. TheDiversificationofCreativeIndividuals

    ArtificialCreativityisaboutmodellingcreativesocietiesandwhilewehave

    restrictedourselvestomodellingproducersthereareseveralotherimportant

    players in these societies that do not directly produce artefacts but are

    involvedinthedistributionandevaluationofthem.

    Tomodelmorecomplexsocialrelationsweshouldimplementmodelsof

    otherindividuals,e.g.consumers,distributors,critics,etc.Eachwouldhave

    their own role to play in simulations of creative societies and would

    influence each others behaviour; consumers would evaluate interesting

    works and pay credits to producers of interesting works, distributorscommunicatetheworksofproducerswidely,andcriticscommunicatetheir

    evaluationsofworkswidely.TheserelationshipsareillustratedinFigure11.

    Usingdifferenttypesofindividuals,wecanbegintomodelsomemore

    of the complexity discussed by Csikszentmihalyi (1999). We could also

    model more complexrelationshipsbetweenagents,such as those between

    designerandclient,byallowingcommunicationofrequirements.Asavery

    simpleexample,aclientcouldcommunicateanexampleworkandinstructa

    producer tomake something like itandexpect the new workto still be

    interesting, i.e. similar-yet-different to the example. Importantly, the

    personalcreativitytestsplayacriticalroleindeterminingthebehaviourof

    allofthedifferenttypesofindividualsandthesocio-culturalcreativitytest

    isstillandemergentpropertyofthewholesociety.

    ProducerandConsumer

    Producer,CriticandConsumers

    Producer,DistributorandConsumers

    Producer

    Consumer

    Distributor

    Critic

    Design

    Evaluation

    Figure11:Threedifferenttypesofindividualswithdifferentabilitiesandtheirrolesinthecommunicationofdesignsandevaluationsincreativedesignsocieties.

    7.4. DOMAINSOFCREATIVITY

    Domainsplayacrucialroleincreativesocietiesbydefiningofthetypesof

    interactions that can take place between individuals within a field and

    betweendifferentfields.Therearemanypossiblescenariosforstudyingthe

    relationship between domainsandthe creativityof individuals and fields.

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    PAPERTITLE 25

    The following discussion provides only a very brief outline of the

    possibilities.

    7.4.1. MultipleDomains

    People that move from one field to another, or contribute to multiple

    domains,are often considered some of the most creative participants.We

    can investigate the mechanisms involved in the creativity of these

    individuals by modelling multiple fields and their associated domains.

    Fields are defined by the communications of the individuals within them,

    creating separate fields means creating groups of individuals that arespecialised in the type of information that they communicate. Effectively

    thiscreatesabarriertoentryfornon-membersofafield.Individualsthat

    transferfromonedomaintoanothermustfindsomewaytoovercomethis

    barrier. One possible isfor agent toapproach the design space ofa field

    whilewithinanotherfield,in asimilarwaythathasalreadybeenobserved

    incliques.Theagentmaythenbeallowedentrancetoafieldbecausethe

    agent producesartefacts thatare appreciatedby themembers of thefield.

    ThisprocessisillustratedinFigure12(a).

    (a) (b)

    Figure12:Bridgingfieldsanddomains.In(a)anagenttraversesadesignspacegetsclose

    enoughtoanotherthedesignspaceofanotherfieldthatitcansuccessfullycommunicatewith

    itsmembersandberewarded.In(b)anagentstraddlestwofieldsandreceivescreditfrom

    membersofbothasittransfersartefactsbetweendomains.Solidarrowsrepresentthetransfer

    ofartefacts,dashedlinesrepresentthetransferofevaluationsorcredit.

    7.4.2. StaticDomains

    Wecandefinestaticfieldsbydefiningthedesignspacetobeexploredbya

    field as a fixed property of its domain. Communication between fields

    exploring different domains will be limited to products that lie in the

    intersection ofdomaindesign spaces.Bysettingup suchenvironmentswe

    can study the spread of ideas through related fields as a consequence of

    interests shared by individualsdifferent domains. Agents that are able to

    locatethemselvesattheintersectionofmultipledomainshavethepotential

    to benefit by addressing a larger audience and by transferring creative

    artefacts from one domain to another. An individual situated at the

    intersectionoftwodomainsisillustratedinFigure12(b).

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    26 A.AUTHOR,B.AUTHORANDC.AUTHOR

    7.4.3. DynamicDomains

    We can alsodefine dynamicfields byallowingindividuals to modify the

    designspaceofthedomain,orbybasingthedesignspaceofadomainon

    the products of another field. Allowing individuals to modify the design

    spaceof a domain wouldallow a designspacetoshiftinthe directionof

    interesting works communicated from other fields. We would be able to

    study a sort of social curiosity as the field moved collectively in the

    directionofnewandinterestingpossibilities.

    D3

    D1 D2

    Figure13:Themovementofdesignspacesasaconsequenceof'collectivecuriosity'.

    7.4.4. HierarchiesofDomains

    Basingthedomainofonefieldonthedomainofanother,wouldallowthe

    investigation of the effects of technological innovation in one domainopeningupnewcreativepossibilitiesinanother.Theexpansionofdesign

    spaces in this way is illustrated in Figure 14 wherethe expansion of the

    design space for domain D2 opens up new possibilities and expands the

    designspaceofdomainD1.

    D2

    D1 D1

    D2

    Figure14:Theexpansionofadesignspaceasaconsequenceofchangesinasubordinate

    domainsdesignspace.

    7.4.5. EmergentDomains

    Oneway to study theemergence of newdomains would betoimplement

    permit the subdivision of a domain when subgroups of its field are

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    PAPERTITLE 27

    sufficiently different that they no longer share a common understanding.

    This process of domain subdivision is reminiscent of speciation in the

    naturalworld.Speciationisaprocesswherebyagroupoforganismsbecome

    differentiatedastheyadapttotheirenvironment.Thedefinitionofaspecies

    isagroupoforganismsthathavebecomesowelladaptedtoeachotherthat

    theycanonlyreproducewithothermembersofthesamegroup.

    Similarly, a field can be defined as a group of individuals that have

    becomesospecialisedthattheyarelimitedtocommunicatingcreativeideas

    toothermembersofthefield.Thedivisionofafieldintotwonewfieldsis

    illustratedinFigure16.Thenewfieldsemergeasthecommunicationlinksbetween two subgroups weaken until they constitute two separate fields.

    Thealreadyobservedformationofcliquescanbeseenasaprecursorofthe

    emergenceofnewfieldsanddomains.

    (a) (b) (c) (d)

    Figure15:Thedivisionofafieldintotwonewfields.

    Speciation is an important topic of research in Artificial Life and by

    adapting some of the mechanisms studied there to model the splitting of

    domainswemaybeabletostudytheemergenceofnewdesignschoolsand

    possiblydesigndisciplinesinartificialsocieties.

    7.5. CREATIVESOCIETIES

    Primarily,ArtificialCreativityisconcernedwiththestudyof theemergent

    behaviour of creative societies. The followingstudies are concernedwith

    the possibilities for experimenting with social conventions, e.g.

    communicationprotocols,toinvestigatetheiraffectsoncreativity.

    7.5.1. CommunicationModels

    ArtificialCreativitysimulationsprovidethenecessarymechanismsforbothdirect and indirect communication. Direct communication is supported by

    thetransmission ofproductsandevaluationsas messages betweenagents.

    Indirect communication is supported by the storage and retrieval of

    symbolic representationsin a domain.Usingthis framework wecan study

    the affects that different communication mechanisms have on the

    developmentofcreativesocieties.

    Oneinterestingpossibilitywouldbetosimulatetheintroductionofnew

    communication technologies and see their affect on the creativity of

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    28 A.AUTHOR,B.AUTHORANDC.AUTHOR

    individualsandsocieties.Forexample,wecanaskthequestion:Whatare

    affects of the introduction of global communication technologies like the

    telephone,e-mailandtheWorldWideWeboncreativefieldslikedesign?

    Eachtechnologyopensupnewpossibilitiesforthecommunicationofideas

    orthecommunicationofdifferenttypesofartefacts.Wewouldanswerthis

    questionbysimulatingsometypicalcommunicationanddomaininteraction

    policiesofindividualsbeforeandaftertheintroductionofglobaldirectand

    indirect communication and observe the behavioural changes of the

    simulatedsociety.

    7.5.2. TheEconomicsofCreativity

    Creativefieldsareconstructedthroughthesocialinteractionsofindividuals

    determined by their communication policies. The communication policy

    implementedin allof thecreativeagentsin thecurrentsystemimplements

    communication of creditfor producing interesting artworks but the credit

    hasnoworthinsidethesimulation,itisimportantonlytoobserverswhocan

    monitorthe creativityof individualsbywatching theircreditratings.This

    doesntreflectthestatusofbeingconsideredcreativeintherealworld.For

    instance, being considered creative imbues a status that can be used to

    attract financial resources. Also, being creative costs, in both time and

    money,andthisforcesanindividualtoconsiderthebenefitsofsearchingfor

    radicallycreativesolutionsagainstthecostincurred.

    7.5.3. ThePoliticsofCreativity

    Givingdifferentcommunicationabilitiestodifferenttypesofagentsmakes

    theselectionofwhichagentstocommunicatedwithanimportantfactorin

    self-promotion of creative individuals. As Csikszentmihalyi (1999) points

    out,convincingotherpeoplethatyouvehadacreativeideaisoftenharder

    thanhavingtheideainthefirstplace.Insocietieswithinunequalstatusof

    individuals,thequestionofwhichindividualstocommunicatewithbecomes

    importantforindividualsseekingtherecognitionfrompeers.

    Agentsinfluencethe behaviour ofotheragentsbycommunicatingtheir

    artworks and their evaluations of those artworks. The current simulation

    modelsaperfectegalitariansocietywherealloftheagentsarecreatedequalandnoagenthasmoreinfluencethananyoftheothers.Wearenotlimited

    to modelling such utopian societies inArtificial Creativity andwith some

    smalladjustmentswecanmodelsocietieswheresomearemoreequalthan

    others.

    By weighting evaluations according to the creativity of the individual

    sendingit,alreadycreativeagentscanpromotethecreativestatureofother

    agentsmore quicklythanuncreative agents.Recognitionbyan established

    creative agent would have a significant impact on the status of young

    agentstryingtogainrecognition.

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    PAPERTITLE 29

    8. Conclusions

    ThecomputationalworkpresentedinthispaperhasillustratedtheArtificial

    Creativityapproachtodevelopingmodelsofcreativesocieties.Byadapting

    Liusdualgenerate-and-testmodelofcreativitywehaveproducedamodel

    of creative societies that can be used to study socio-cultural creative

    behaviour as an emergent propertyarising fromthe creative behaviour of

    individuals. The implemented system models the evolution of notions of

    creativitywithinanartificialsocietyovertimeasindividualscomeandgo,

    thefieldchangesincomposition,andthedomainisaltered.The emergence of social behaviour, e.g. The Law of Novelty, and

    dynamicsocialstructures,e.g.cliques;suggestthattheArtificialCreativity

    approach to developing models of creative societies may contribute new

    insightsintothenatureofcreativedesigninsocio-culturalsituations.Figure

    14 illustrates the different levels at which creativity may be studied as a

    pyramid ofemergentproperties.Eachlevelrepresentsa differentaspectof

    creativity that is emergent from the ones below it. Layers that represent

    processes are coloured darker than those that represent products, process

    andproductlayersalternateupthepyramid;propertiesofcreativeproducts

    are a consequence of the processes that created them and the behaviour

    higher-levelprocessesareaffectedbytheproductsthattheyoperateupon.

    Eachlevelinfluencesthelayersbelowthembyprovidingasituationfortheproducts andprocesses. Forexample, emergent social structures influence

    the communication of products and the products communicated influence

    thebehaviourofindividualsthatsendandreceivethem.

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    30 A.AUTHOR,B.AUTHORANDC.AUTHOR

    Individual

    Processes

    Individual

    Products

    Individual

    Behaviours

    Communicated

    Products

    Social

    Behaviour

    CulturalProducts

    Emergence Influence

    Figure16:Apyramidofcreativity.

    Thefoundationsofthecreativepyramidaretheprocessesinternaltothecreative agent that allows it to generate-and-test ideas. The result of

    executing these processes is the creative products. Traditionally,

    computational research has concentrated on thesetwo levels byencoding

    processesthoughtto be important increativityina pieceof software and

    getting experts to examine the results of running those processes to

    determine whether the processesare creative. Intraditionalcomputational

    models,thehigherlevelsofthepyramidarenotmodelledinthesoftware

    andareprovidedbypeople.

    ArtificialCreativitysuggestsa differentapproach;insteadofevaluating

    the products of a piece of software to determine its creativity, it focuses

    uponthebehavioursofagentsandartificialsocieties.ArtificialCreativityis

    concerned with modelling the creative behaviours of individuals, e.g.curiosity,andstudyingtheemergentsocialbehaviourswhenindividualsare

    puttogether.BecauseindividualsinanArtificialCreativitysimulationmust

    beabletoevaluatethecreativityofcommunicatedproductsandhenceother

    individuals,thedetailsoftheproductsofindividualsbecomelessimportant.

    More important in the study of Artificial Creativity are the socio-cultural

    structuresthatemergeasaconsequenceof thecommunicationofproducts

    andevaluations.

    The Artificial Creativity approach permits the computational study of

    highestlevelsofcreativityillustratedinFigure14withouthavingtodevelop

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    PAPERTITLE 31

    agents that can integrate, and achieve creative status, in human society.

    ArtificialCreativity simulations permit theexperimentationwith creativity

    in artificial societies thatwouldbeimpossible in therealworld,allowing

    thestudyofcreativity-as-it-isinthecontextofcreativity-as-it-could-be.

    Acknowledgements

    Tocome

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