Untangling the Social Network of Musicians StefanJänicke stjaenicke@informatik.uni-leipzig.deLeipzigUniversity,GermanyJosefFochtjosef.focht@uni-leipzig.deLeipzigUniversity,Germany

Introduction As opposed to the former idea of creative auton-

omy,inrecentyears,humanitiesresearchtendstoin-vestigateculturalcontextsandcircumstances,inspira-tionalmodels, and theways that knowledge, experi-enceandexpertisehavebeen transferredover time.Weaddressthequestionof"creativetransfer"withinthefieldofmusic.Duetotheeverlastingsignificanceofmusicalworks,relationshipsbetweenmusicians–theentrypointforsuchaninvestigation–arewelldoc-umentedinarchives,librariesandmuseums.Inprintmedia,usuallyonlyasinglerelationbetweentwomu-siciansisnarrated.Furthermore,itiscommonforthebiographyofonlyoneofthetwomusicianstoreporton the relationship. Larger overviews of social net-works between several musicians seldom exist. Alt-houghsomedigitalresourcesexist,theseareoftenre-ducedtothemilieuxofpopularmusicianslikeMozartandBeethoven.

Since2005,musicologists of theprojectBavarianMusiciansEncyclopediaOnline(BayerischesMusikerLexikonOnline,BMLO)havesystematicallycollectedbiographicaldata(anexampleisgiveninFigure1)andexaminedrelationshipsbetweenmusiciansfromprintmedia–atediousworkthatresultsinauniquedata-baseofgreatvalueformusicology.TheBMLOcontainsmusicians fromallkindsofmusicalprofessions(e.g.,composers, singers, musicologists, instrument mak-ers,...),mostofwhomhadanactivelifetimeperiodliv-inginBavariaoraconsiderableinfluenceonBavaria.Nowprovidinginformationaboutaround28,000mu-sicians,theBMLOhasachievedglobalscope,onethatisunderpinnedbythemanymusicologistsworldwidewhousetheBMLOfortheirdailywork.

Figure 1: Biographical information about Robert Schumann in the BMLO. Alongside information about a musician’s life-time, denomination, professions or places of activity, the da-tabase provides a number of relationships by type. Next to his partner Clara Schumann, further relations are listed to Robert Schumann’s father in law, to his students, colleagues, and other acquainted musicians in his social network

Inearlierworks,wedevelopedvisualinterfacesonthebasisoftheBMLOdataforprofilingmusicians(Jä-nickeetal,2016),andforthedistantreadingofmusi-cians'biographies(Khulusietal,2016).However,thesocialnetworkinherentintheBMLOhasremainedun-touched so far.Using theBMLO, only the social net-work of singlemusicians can be observed, as is thecasewhenusingprintmedia.Inordertofacilitateanextensive analysis of the entire social network con-cealedintheBMLO,wedesignedavisualizationthatbringstogetheralloftherelationshipsintheformofaninteractivesocialnetworkgraph.Incontrasttopre-viousmeans of investigating the transfer ofmusicalknowledge,we allow for the dynamic exploration ofrelationshipsamongmusiciansovergenerations.

Graph Topology Informationregardingrelationshipstoothermusi-

ciansinthedatabaseisprovidedfor9,805musiciansof the BMLO. Only one relation exists for around46,5%ofthesemusicians,andjust261musicianshaveten or more relations. Adolf Wilhelm August Sand-berger is themusicianwithmost relations (97).Theaveragenumberofrelationsformusiciansis2.6.Theresultant graph structure of the social network con-sistsof1,420connectedcomponents,thelargestcom-ponentconnects5,539musicians, thesecond largestonly56musicians–1,385connectedcomponentscon-tainlessthantenmusicians.

Duetotheabovementionedtopologicalfeaturesofthe graph, the typical, straightforward visualizationusinga force-directed layoutapproach,e.g.,byusingtoolssuchasGephi(Bastian,2009), leadstoaglobal

overviewof the socialnetwork (seeFigure2).How-ever, local structures are hardly readable, whichmakes an interactive exploration nearly impossible.Theobjectiveofthisworkwastodevelopagraphde-signthatmakesthesocialnetworkofmusiciansvisu-allyaccessibleforthefirsttime,and,moreover,capa-bleofbeingexploredinaccordancewiththeresearchquestions of the collaborating musicologists. We fo-cusedonthelargestconnectedcomponentthatcausesthegreatestchallengesforthistask.

Figure 2: The largest connected component with 5,539 musi-cians visualized using Gephi.

Graph & Interface Design to Analyze Teacher-Student Relationships

The preliminary step when generating the socialnetworkgraphisfilteringaccordingtotheunderlyingresearchquestion.At first,a filteringcanbedonebyrelationshiptype(s).Second,itispossibletofocusex-clusivelyonmusicianswithspecificprofessions(e.g.,instrumentalists). In the followingdiscussion,we fo-cusonthemotivatingexampleforthiswork:theanal-ysis of teacher-student relationships to investigatehow musical knowledge, experience and expertisehavebeen transferredover time.The correspondingfilter keeps 3,994 musicians, the largest connectedcomponentofthissub-network–theresearchobjectofthemusicologists–contains2,769teachersandstu-dents.TheGephioutputforthisgraphisgiveninFig-ure3.

Figure 3: The largest connected component of the teacher-student network with 2,769 musicians visualized using Gephi.

Althoughthestructuresareslightlyfinerduetothere-duced number of nodes and edges, the highly con-nectedpartintheinteriorofthegraphremainsclut-tered.Here,welistourdesigndecisionsappliedinor-dertogenerateareadablegraph(seeFigure4)andanavigableinterface.

Figure 4: The largest connected component of the teacher-student network with 2,769 musicians (608 nodes) visualized with our method.

• Temporallyalignedgraph:Itwasparticu-larlyimportantforthemusicologiststhatthegraphlayoutincludesatemporaldimension,sothatrelationscanbechronologicallyana-lyzed from left-to-right. Therefore, we ap-pliedaforce-directedgraphlayoutandusedfixed x-values that represent a time-stamp,whichreflectsthemiddleofamusician’scre-ative lifetime(seeJänicke2016),onahori-zontaltimeaxis.Asaresult,thenodesonlyspread vertically and the chronological or-derremainsintact.

• Nodegrouping:Becausetheunderlyingre-search question investigates transfer pathsofmusicalknowledge,wehidethenodesofmusicians who never had the role of ateacher.Still,thesemusiciansaregroupedtotheirteachers,andcanbeaccessedintheex-ploration process. This design decision re-duces thenumberofnodes tobedisplayedfrom2,769to608.

• Node layout: To illustrate the significanceand the influenceofpersonalities, thesizesof nodes reflect the number of students ofthe corresponding teachers, which makesteacherswithmanystudentssalient.Perde-fault,nodelabelsarehidden,butfornaviga-tion purposes, a user-defined number ofnode labels with the corresponding musi-cians names can be shown on demand. Ei-ther the most popular musicians or theteachers with most students can be high-lighted.

• Interactivity:Hoveringoveranodeshowsthecorrespondingmusicianandtwolistsofstudents (those who became teachers andthosewhodidnot)inapopupbox.Clickinganodehighlightsallconnectionstoateacher’sstudentswhobecame themselves teachers.This way, transfer paths of musicalknowledgecanbeassembledinteractively.

• Musicalprofessionanalysis:Fortheselected(via mouse click) musicians in the graph, theevolution of musical professions can be ana-lyzed.Therefore,allmusicalprofessionsoftheteachers’studentsarelistedbydecreasingfre-quency. For each profession, a bar chart illus-trateswhentheyhavebeenpursued.

Analysis of Teacher-Student Relationships

This section outlines a usage scenario of theteacher-studentnetworktakingtheexampleofAdolfWilhelmAugustSandbergerwhoestablishedmusicol-ogyasasubjectofstudyinMunich.

First,wecompareSandbergertooneofhisteach-ers,JosephRheinberger,bothbeingtheteacherswiththe highest numbers of students (the BMLO lists 97students for Sandberger and 87 students for Rhein-berger).Ofspecialinterestwasthecomparativeanal-ysisofthemusicalprofessionsoftheirstudentsinor-der toassess thesimilarityofboth teachers’ studen-tries.Figure5showsthetwoselectedteachersinthesocialnetwork,andaviewatthesummarizedmusicalprofessionsoftheirstudentsisgiven.Whilecomposi-tionwasthemajormusicalprofessionofRheinbergersstudents (70x), this number drops for Sandbergersstudents(52x).Ontheotherhand,thenumberofmu-sicologists increase (10x → 65x). Other significantchangescanbeseen for theprofessionschoirmaster(29x→9x),organist(19x→8x),musicwriter(12x→29x)andmusiceditor(5x→26x).Thus,thevisualiza-tionreflectsachangeofthemusicalprofileofbothstu-dentriesfromcompositiontocompositionscience–ahypothesisthatcouldbeverifiedwithoursystem.

Second,weexaminedthechangeofteachingsinceSandbergerestablishedmusicologyinMunich.There-fore,weobservedthemusicalprofessionsofthestu-dentsofSandbergerandhissuccessorsinMunich,Ru-dolfvonFicker,ThrasybulosGeorgiosGeorgiadesandTheodorGöllner(seeFig.6).Whilethemusicologististhemostfrequenttaughtmusicalprofession,thecom-poser gets less and less important. The last teacherTheodorGöllner evenhadno studentwith the com-poser as musical profession. Thus, the change fromcomposition to composition science that alreadystarted with Sandberger compared to Rheinberger,steadilycontinuedwithSandberger’ssuccessors.

Figure 5: Comparing the students of Joseph Rheinberger

and Adolf Wilhelm August Sandberger.

Figure 6: Temporal change of teaching in Munich.

Conclusion Throughclosecollaborationwithcomputerscien-

tistsandmusicologistsimplementingauser-centereddesignapproach,wedevelopedavisualizationthatal-lowsforthedynamic,interactiveexplorationoftheso-cial network of musicians, focusing primarily onteacher-student relationships. In contrast to out-of-the-box tools likeGephi,we took the researchques-tions of the collaboratingmusicologists into accountwhendesigningthegraphandtheuserinterface.Alt-houghdetailed informationabout individualrelationperiodsbetweenmusiciansaswellasthetaughtmusi-calprofessionsarenotincludedintheunderlyingda-tabase,theprovidedinterfacefacilitatesanovelviewon the social network ofmusicians,which allows todraw conclusions on the question of the transfer ofmusicalknowledge.

ThevalueofoursystemforusersoftheBMLOisnotonly that social networks are visualized for the first

time,butalsothatthegraphmaybefilteredinaccord-ancewiththewaythatspecificresearchquestionscanbeinvestigated.Nexttoteacher-studentrelationships,familialorlaborrelationshipsalsocreatevaluablenet-workstobeexplored.Furthermore,itispossibletoan-alyze sub-networks concerning musical professions,and tocombinerelationship typeswithmusicalpro-fessions. For example, when combining teacher-stu-dentrelationshipswiththemusicalprofessioninstru-mentalist (see Fig. 7), Wolfgang Amadeus Mozartshowsupat thebeginningof the instrumentplayingknowledgetransfer.

Figure 7: Teaching instrumentalists.

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