Auguste Rodin Draws Blind:Tchalenko, John; Miall, Rowland

DOI:10.1162/LEON_a_01553

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Citation for published version (Harvard):Tchalenko, J & Miall, R 2017, 'Auguste Rodin Draws Blind: An Art and Psychology Study' Leonardo, pp. 1-17.https://doi.org/10.1162/LEON_a_01553

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AugusteRodinDrawsBlind:AnArtandPsychologyStudyJohnTchalenkoandR.ChrisMiallJohnTchalenko(researcher),UniversityoftheArtsLondon.Address:272HighHolborn,LondonWC1V7EY,UK.john@tchalenko.comR.ChrisMiall(neuroscientist),SchoolofPsychology,UniversityofBirmingham,Birmingham,B152TT,UK.r.c.miall@bham.ac.ukABSTRACTLateinhislifeRodinproducedmanythousand‘instantdrawings’.Heaskedmodelstomakenaturalenergeticmovements,andwouldsuddenlydrawthemathighspeedwithoutlookingathishandorpaper.Tohelpunderstandhis‘blinddrawing’process,eyeandhandmovementsofartstudentsweretrackedwhiletheydrewblind,copyingcomplexlinespresentedtothemasstaticimages.Thelineshapewascorrectlyreproduced,butscalingcouldshowmajordeficienciesnotseeninRodin’ssketches.WeproposethatRodin’sdirectvision-to-motorstrategy,coupledwithhishighexpertise,allowedhimtoaccuratelydepictinonesweeptheentiremodel,without“thoughtsarrestingtheflowofsensations.”

INTRODUCTIONDuringthelast20yearsofhislife,thesculptorAugusteRodin(1840--1917)abandonedsomewhatsculpturetoproduceseveralthousandwonderfuldrawingsofaspecialkindwhichhereferredtoashis‘instantdrawings’(dessinsinstantanés).Hewouldaskhismodelstomovenaturally,inanywaytheywanted,butwithenergeticandrapid–evenacrobatic–movements.Hewouldthensuddenlydrawthematgreatspeedandwithouteverlookingathishandorthepaper.Theresultingpictureswereamazingeventhoughtheycontainedtheoccasionalmisplacedlines.NadineLehni[1],formerchiefcuratorattheMuséeRodinParis,explainedtoTchalenkoin2011whatadrawingsessionwithRodinwouldhavelookedlike:“Hehadalwaysbeendrawingfromimagination,butfromabout1900onwards,hecreatedacompletelynewwayofdrawing.Everyday,professionalmodelswouldcometohisstudio,andRodinwouldaskthemtobeasnaturalaspossible.Heneveraskedthemtoposeortotakeattitudestoconveyfeelings–--hewasnotinterestedinthat.Hewantedthemtoactnaturalandtohavevividmovements:torun,todance,tocombtheirhair,tokneelonthefloor,etc.Rodinwasseatedinachair,asheetofpaperonacardboardheldonhiskneesandapencilinhishand.Buthewasonlyfollowingthemodel’smovementswithhiseyes–sometimesonemodel,sometimestwo–andhewaslookingatthemveryattentively.Suddenly,amazedbysomemovementthatseemednewtohim,oracrobaticorfullofvitality,hewouldseizehispenciland,withoutremovinghiseyesasingleinstantfromthemodel,hewouldtraceatanextraordinaryspeedtheoutlineofwhathesawinfrontofhim.Andthatwasunique,anewprocess,averydifficultone-inaway,theexplanationoftheextraordinary

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vitalityofhisdrawings;hewasdrawingwhathewasseeing,notseeingwhathewasdrawing”.RODIN’SINSTANTDRAWINGSRodinseemstobetheonlyartisttohavesystematicallyusedblinddrawinginthiswayalthoughteachersofdrawinghavesometimesadvocatedasimilar‘blindcontour’methodasausefultrainingexercises[2,3].Theinstantdrawings,firstcreatedasstartingpointsforfurtherwork,werealsoamazingasfinishedsketchesdepictingextremelycomplexmovementsofthehumanbody.Attimes,however,thedrawnlinewouldgooutofthepaper’sboundaries,atwhichstagetheartistwouldredrawthemissingelement--stillwithoutlooking--elsewhereonthepaper.Figure1showsthistakingplacewiththemodel’sleftarmandhand.Therightarmandhand,possiblythelastlinesdrawnonthepaper,arealsoremarkablebutforadifferentreason:thehandisseeninaclutchingattitude,mostprobablymeantfortheanklebutmissingitbyaboutonecentimeteronthepaper.Thissuggeststhat,havingdrawnthewholefigureessentiallyinonesweepwithoutlookingatthepaper,theartistlandedtherighthandwithinacentimeterofitsintendedposition.Inacommenttohissecretary,Ludovici,Rodinexplainsin1906:“NotoncewhiledrawingthecontourofthisformdidItakemyeyesoffthemodel.Why?BecauseIwantedtobesurethatnothingwoulddistractmefrommyunderstandingofthemodel.Thusnotathoughtaboutthetechnicalproblemofrepresentingitonpaperwasallowedtoarresttheflowofsensationsfrommyeyestomyhand.HadIlookedatmyhandthisflowwouldhaveceased”[4].AlthoughRodinhadbeendrawingsincehisyouth,theoriginsofhisblinddrawingmethodweresituatedinhissculpturalwork.In1880hereceivedacommissionfortheGatesofHell,amonumentalthree-dimensionalpanel6mhigh,4mwideand1mdeep,comprising180figuresdepictingascenefromDante’sDivineComedy.Rodinworkedforawholeyearonpreparatorydrawingsfromimaginationforthisworkbeforeabandoningtheapproach,consideringthatalthoughhisdrawingsdidrenderhisvisionofDante,they“werenotsufficientlyclosetoreality”.Hedecidedtostarteverythingagain,workingfromnaturewithmovingmodelsandmodelingeachfiguredirectlyinclayfromlife.Pinet,2006[5]mentionsthathemodeledtheclaywithextraordinaryease,nevertakinghiseyesoffthemodelandforgettingthepresenceofhisvisitorswhowerefascinatedtoseeafaceortorsoemergefromhishandswithinjustafewminutes.In1896hisfriend,R.Marx,mentionedseeing“aseriesofdrawingsnolongerdonefrommemory,butusingamodel”[6].ThefirstofficialmentionthatthismethodwasalsocenteredonthepracticeofworkingblindwithouteverlookingatthepaperappearedinanarticlebytheartcriticClément-Janinin1903[7].Thesculptorhadsuccessfullytransferredtodrawingaworkingmethodthathehadhithertoreservedformodelingfigures,withtheaimofcapturingthemovementofhismodelswithoutimposingonthemtheconstraintsofaclassicalpose.

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Figure1.Modelstandingonherrightfootwhilebendingherleftlegbehindher.Themodel’sleftarmandhandareoutofframebutredrawnfurtherdown.Inreallife,themodel’srighthandwasprobablyclutchingherleftankle,butRodin’sblinddrawingcausedthehandtomisstheanklebyaboutonecentimeter.Therighthand’sstrength-clutchattitude,thelefthand’scounterbalancingposition,thehead’stiltandthediagonalshouldersexpressthebody’smovementatthevergeofinstability.Contrasthasbeendigitallyenhancedtoincreasevisibilityoftheinitiallines.{D.518_Lores.JPEG}Ludovicialsocommentsonthepossiblemishapswhendrawingwithoutlooking.Referringtotheupperlegasitappearsinaparticulardrawing--possiblytheoneshownhereinFigure2--hewrote:“Inoticedthathekepthiseyesfixedonthemodel,andneverlookeddownathispencilorthepaperonwhichhewasdrawing.(…)Thiswaywouldproducefrequenterrors:forinstance,thefinalstrokeof,say,therightsideofaleg,wouldbebroughtdownsoveryfarwideofthestrokerepresentingtheleftsidethatthecreaturedrawnlookedasthoughshehadelephantiasis”[8].Theoppositeeffectisperceptiblebelowtheknee,withathinningofthelowerlegwellbeyondrealisticproportions.Inbothcases,theerrorstemsfromaninaccuratepositioningofalineonthepicture,thelineitselfbeingcorrectinshapeandsize.Forconvenienceofdescriptionweshalltermsuchinstances‘misplacement’errors(seeGlossary).ItisnotknowwhatLudovicimeantwhenreferringtosucherrorsasbeingfrequent,butinthecontextoftheseveralthousanddrawingswhicharestillavailabletoday,theseerrorsconstitutelessthanafewpercent.Nevertheless,weshallseethattheyareimportantfortheunderstandingofRodin’swayofdrawing.

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Figure2.Theoutlineofthemodel’sshoulderandback,firstdrawnblindusingawavyline,islaterdrawnsightedasadarker‘rightline’.Therighthandwhichhasgoneoutofthepictureisrepeatedlowerdown.Theleftarmandhandareshownintwoconsecutivepositions,revealingthespeedofRodin’sdrawingaction.Theoutercontourlineoftherightlegismisplaced:forreasonsunknowntous,theartistseemstohaveliftedhishandfromthepaperwhiledrawingthethigh,subsequentlystartingagaintoolowinthepicture.Contrasthasbeenenhanced.{D.5523_Lores.JPEC}

Whenaninstantdrawingwasfinished,Rodinwouldthrowitonthefloorandimmediatelystartonthenextone.Attheendofasessionhewouldpickupthesheetshelikedbestand,nowlookingatthedrawing,hewouldreinforceanexistingline,oraddadarkerone,whichhereferredtoas‘therightline’(letraitjuste).Figure2showsthisforthemodel’sback.Somedrawingswouldthenberetracedandsubmittedtofurtherchangessuchascropping,toning,tintingandcollageassembly.Someoftheresultingpictureswereeventuallyshowninexhibitions,althoughtheoriginalinstantdrawingsremainedprivateandwereonlyeverseenbyafewofRodin’sfriendsandartcritics.BLINDDRAWINGOBSERVEDWITHTHEEYETRACKERPreviousobservationsWehavepreviouslyreportedtwotypesofblinddrawingincontemporaryartstudents,whichwetermeddirectblindcopyinganddirectcopying[9].Inthepresentstudywerefertotheentitybeingcopied(thepsychologist’s“stimulus”)astheoriginalandtotheproduceddrawingasthecopy.Indirectblindcopyingtheoriginalwasitselfalinedrawing

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placedonaverticaleasel,andthesubjectwasgivenasketchpadtoholdonhis/herlap.Thesubjectwastheninstructedtocopytheoriginalwithoutlookingatthesketchpad.Ourtwoprincipalobservationswerethatperceptionoftheoriginalanddrawingofthecopycouldtakeplaceconcurrentlyandthatshapewascorrectlyrenderedbutspatialpositionandscaleweredefective.WebelievethatdirectblindcopyingiswhatRodinwasdoing,althoughatthetimewedidnotrealizethisconnection.Incontrast,fordirectcopyinganoriginalsketchofacartoonfacewascopiedontoanadjacentpaperwiththehelpofgazeshiftmovementsbetweentheoriginalandthecopy.Inthisexerciseweobservedrepeatedepisodesofblinddrawing.Astheeyeshiftedbackandforthbetweenoriginalandcopyshortperiodsofblinddrawingwereincorporatedintothenormalgaze-shiftrhythm.Forexample,thehandwouldstartdrawingthecopywhiletheeyewasstillontheoriginal,ortheeyewouldmovebacktotheoriginalwhilethehandcontinueddrawingthecopy.Oursubjectsintheseeyetrackertestswerefirstyearart-schoolstudentsandtheydifferedintheamountofblinddrawingtheywereusing.However,whenaskedtodraw100%blind,i.e.keepingtheireyesonlyontheoriginal,likeRodin,eventhemostexperiencedwerepronetoseveredrawingerrors.Typically,havingstartedablinddrawingexerciseatoneparticularscale-say1to1p-subjectswouldsubconsciouslychangescalesduringdrawing,sometimesmorethanonce.Theresultwouldthenbeabiggerorsmallercopycontainingfurtherinternalsizeinconsistencies.Thepresenteye-handinteractionstudyInordertogainabetterunderstandingofthesedrawingerrors,andinparticulartoexaminewhethertheyrelatedtoRodin’smisplacementerrors,wereporthereaprogramofeye-trackingtestswithagroupof7art-schoolstudents.Eachstudentwasaskedtoperformthreedirectblindcopyingtestsandthreedirectcopyingtests,thelatterchosenatthreedifferentoriginal-to-copyseparationsinordertoassesswhethergreaterseparationsintroducedmoredrawingerrors.TheresultsoftheseriesofcopieddrawingswerequantitativelycomparedwiththeoriginalsusingProcrustesanalysis[10]-arigidshapeanalysistechniquethatallowsseparatecalculationofshape,scaleandrotationaccuracies.Followingabriefsurveyoftheexperimentalmethodsusedwedescribebelowthemainfeaturesseenduringdirecttracingofanoriginalline,blindcopyingoflineswithoutvisionofthedrawncopy,andthemorenaturaldirectcopyinginwhichthegazeshiftsperiodicallybetweentheoriginalandthecopy.TestingmethodExperimentalsetupSubjectswearingahead-mountedeyetrackerwereseatedabout55cmawayfromaverticalgraphicstabletscreen.Forthatdistance,1degreeofvisualanglecoversascreenareameasuringapproximately1cmindiameter.Forright-handedsubjects,thescreen’slefthalfactedasdisplaymonitorcontainingtheoriginalimagetobecopiedandtheright

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halfactedasgraphicstabletonwhichthecopywasdrawnwithastylus.Ascanconverterrecordedtheentirescreencontinuouslyasanaudiovisualvideofile(avi)withtheeye’spositionasprovidedbytheeyetrackersuperimposedasacursor(thatwasnotseenbythesubject)andprovidingadetailedrecordoftheprogressofthelinebeingdrawn.Simultaneously,thecombinedeyetrackerandstyluspositionparameterswererecordedasdigitaldatafilestobeusedinthetestanalysis.Theeye-trackerapparatususedwasthehead-mountedASL501(AppliedScienceLaboratories,Bedford,MA)runningat50Hz.HeadpositionwasmonitoredwithanAscensionFlockofBirdsmagnetictracker,andtheintegratedsystemprovidedfixationaccuraciesbetterthan1degree.Thegraphicstablet/monitorwastheCintiq21UX(Wacom)withascreensizeof432x324mmandadisplayandrecordingresolutionsetat1024x768pixels.Drawingtookplacewithastylusdirectlyonthescreen.Thestyluspositionwassampledevery40msataresolutionof1pixel(betterthan0.5mm).Foranalysispurposesaverticallineplacedmid-waybetweentheoriginalandthecopywasusedtoseparateoriginalandcopyareasofinterest.Originalandcopygazeonsetsandterminationswerethenrecordedastheeyecrossedthiscentraldividinglinefromwhichgazedurationscouldbededucedfortheoriginalandthecopysidesofthescreen.Similarly,thestartandendofactualdrawingwererecordedandblindandsighteddrawingdurationsmeasuredforperiodsofactivedrawingwhengazewasdirectedtoeithersideofthedivide.BlindtestsetupFortheblinddrawingsituations,subjectsweretested3times,eachtimewithadifferentoriginalstimulus.Intheblind/occludedtestsB1andB3,respectivelythefirstandlastoftheseries,theoriginalandthecopywere15oapartandseparatedbyaphysicalvisualoccludermakingitimpossibletoseethecopy,eitherfoveally(incentralretinalvision)orperipherally,duringdrawing.Theblind/instructedtestB2wasperformedwithouttheoccluder,thesubjectbeinginstructednottolookatthecopy.Thelargestseparation(30o)wasselectedforthistestinordertomakeperipheralvisionasdifficultaspossiblegiventhegeometryofourexperimentalsetup.Post-testchecksoffixationlocationsfromtheeye-trackingrecordverifiedthattheseinstructionshadbeenfollowed.OriginalsTheoriginalforeachtestwasacomplexverticalline20cmlongmadeofasuccessionof20simplelineseachuniformlycurvedorstraight.Changesindirectionfromonesimplelinetothenextwerealwayslessthan±90o,whichmeantthatalineneverwentbackonitself.Eachcopyingtestwasassociatedwithadifferentoriginalline.Alldrawingwasinstructedtoproceedfromtoptobottomofthepaper,startingatapre-markeddotonthecopysideofthedigitizingscreen.OrderoftestingTheorderoftestingwasasindicatedinTable1.Theserieswasstartedwiththesimplesttask–tracing-inordertointroducethesubjecttotheexperimentalsituation.ThiswasfollowedbythefirstblindtestB1(withoccluder)inwhatwasthesubject’sveryfirstencounterwiththenotionorpracticeofblinddrawing.Withthistestandwithitsrepeat

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B3,theactualoriginaltocopydistanceistheoreticallyarbitraryasthesubjectcannotseethecopy.Thethreedirectcopyingtestsatdifferentangularseparationsweregroupedtogetherinordertokeeptheexperimentalconditionssimilarthroughout.Theangleswereselectedas30o(maximumofthepresentsetup),8o(assumedlimitofparafovealvision)and15o(halfwaybetweenthetwoextremes).ThelasttwotestswereB2(blindwithinstructions)andB3(blindwithoccluder),thelatterrepeatingB1toassessthepossibilityofskilllearningduringtheearliertests.SubjectsThe7testsubjectswere2ndyearstudentsatCamberwellCollegeofArts,UniversityoftheArtsLondon.Fivewerestudentsinthepaintingorfineartscourseandhadexperienceindrawingfromlife.Forexample,subjectSShadbeendrawingquiteregularlyinsecondaryschoolandartcollegefoundationyearandwasfamiliarwithportraiture,landscapeandexactcopying.Intheanalysiswhichfollows,testresultswillbefrequentlycomparedtoresultsfromSSwhoseblinddrawingbehaviorwasparticularlyclear.Howeverthissubjectwasatoneextremeofthespectrumintermsofthemetricsoftheeyeandhand.Allsubjectsgavewritteninformedconsenttothetests,whichhadtheapprovalofthelocalethicalcommittee.AccuracyanalysisTocomparetheaccuracywithwhichthecopiedlinewasreproducedfromtheoriginalweusedProcrustesanalysisunderMatlab(v7.5,TheMathWorksInc.).Procrustesisarigidshapeanalysisusingasetoflineartransformations(isomorphicscaling,translation,androtation)tofindthebestfitbetweentwosetsofspatialdatapoints.Thedigitalrecordofeachdrawnline,andeachoriginalstimulusline,wasfirstresampledto100equallyspacedlocations.Thetwosetsof100datapointswerethensubjectedtoProcrustesanalysis,tofindthelineartransformationsnecessarytobestmatchthecopywiththeoriginal.Weinvestigated3typesoferrorinordertoquantifyobjectivelythedrawnsize,itsorientationandaccuracyofshape.Wedefinedsizeasthescaleerrorbeingtheabsolutedeparturefromperfect(1.0),asquantifiedbythescalingcomponent.Hencealinedrawnscaledby0.9or1.1comparedtotheoriginalsizewouldbegivenascaleerrorof0.1,andeachwouldrepresentadrawing10%toosmallortoobig.Wedefinedrotationerrorasabsolutedeviationfromperfect(0o),asquantifiedbytherotationalcomponent(maximum=90o),withpositivevaluesindicatingacounter-clockwiserotationofthecopiedshape.Theshapeerrorwasthendefinedasthedeparturefromperfect(0),asquantifiedbytheinverseofthegoodness-of-fitcriterion,thesumofthesquarederrorsbetweenthetwooptimallytransformedlines,normalizedtoamaximumof1.0.Allerrorswerethenexpressedinpercentages.Eye-handmetricsWecomparedgazeanddrawingratiosbydefiningthegazeratio(G)astheratiooforiginalgazetocopygazedurations,anddrawingratio(D)astheratioofdrawingtimeoccurringduringgazeontheoriginaltodrawingtimeoccurringduringgazeonthecopy[11].AzerovalueforDindicatednoblinddrawing,andavalueofgreaterthan1indicatedmoretimespentblinddrawingthansighteddrawing.Theamountofblinddrawingmayalsobeexpressedintermsofa‘blind-to-total’ratio(B)varyingbetween0%and100%.

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Tracing:Eye-handinteractiontestsandaccuracyTracingoveranoriginallineisanentirelysightedtaskthatprovidesausefulbasisforcomparingeye-handinteractionsanddrawingaccuraciesduringblindandgaze-shifttestsAllsubjectswereobservedtotraceovertheoriginallineinshortstrokesbroadlymatchingthesimplelinestructureoftheoriginal(Figure3leftpanel,thegreyline).Fixationswereoftheposition-locktype(seeGlossary)andtheirtimingwassystematicallyaheadofthehandbyaboutonesegment.Forexample,onFigure3weseethatdrawingstartedwiththegazelockedonpoint1whilethefirstline1(madeupoftwosegments)wasdrawn.Thegazethenmovedtopoint2whiletheshortverticalline2wasdrawn.Thiswasfollowedbythegazelockingontopoint3whilethecurvedline3wasdrawn,etc.Asexpected,errorsintracingwerenegligible(Table1):taking0%asrepresentingperfectaccuracy,shapeerrorwas0.2%,scaleerror1.2%(i.e.aslightmagnification)androtationerror0.1%(amodestanti-clockwiserotation).PARAMETER TRACE B1 8o 15o 30o B2 B3

shape% 0.2(0.3) 1.1(0.8) 1.1(0.6) 0.7(0.4) 1.7(1.1) 1.7(0.7) 1.1(0.5)

scale% 1.2(0.6) 25.4(11.4) 1.7(1.3) 3.5(0.3) 7(4.9) 14.7(8.8) 15.7(9.3)

rotate% 0.1(0.2) 6.3(5.0) 5.1(4.8) 4.2(1.7) 3.9(3.1) 6.3(3.3) 6.9(3.6)

Table1.MeanProcrusteserrorsofshape,scaleandrotationfor7subjectstracingordrawingcomplexlines.TestsB1andB3wereblindcopyingwiththedrawingareaoccludedfromview,whileB2wasblindbyinstructiontolookonlyattheoriginal(seetext).The8o,15oand30ocopyingtestsallowedthegazetoshiftbackandforthasthevisualanglebetweenoriginalandcopywasincreased.Alldataarethemeans(n=7)withstandarddeviationsshowninparenthesis.Blindcopying:Eye-handinteractiontestsandaccuracyInourearlierexploratorystudyusingcartoonfaces[13],wehadfoundthattheeyegenerallyprecededthehandattheface’smainfeatures:nose,lips,chin,etc..Thepresenttests,usingmoreabstractandcomplexoriginals,confirmedthattheeyewassystematicallyaheadofthehandbyonetofoursimplelinesegments,dependingonthesubject.Intheblind/occludedtestperformedbySSillustratedhereinFigure3(centreandright),fixationsadvanceddownwardalongapathroughlybisectingtheoriginallineandwiththeeyeaheadbyabouttwosimplelines.Thevisualinformationrequiredtodrawthelinethusseemedtobeencodedsystematicallyaheadoftherenderinghand.Fixationseitherlandedontheoriginalline(e.g.4,8,10,13)oronpointsrelatedgeometricallytotheoriginalline(e.g.5,7,12).Inthelattercasefixationsappearedtobelocatedneartheoriginofthecorrespondingarcs.Thispatternwascommontoallsubjectswithoneexception,subjectCAwho,inthisasinallothertests,proceededveryslowly,simplelinebysimpleline,withmanyrepetitions.Theblind/instructedtests(B2)thatpotentiallyallowedsomeperipheral

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visionproducedresultsinallrespectssimilartothefullyblind/occludedtests,suggestingthatperipheralvisionwasnotplayinganimportantpartinthedrawingstrategy.

Figure3.ComparisonofsubjectSStracing(leftpanel)andblind/occludedcopyingB1(centreandrightpanels).Theoriginal‘to-be-copied’lineisshowninblack,thecopiedline,ingrey.Thenumberedblackdotsindicatethesequenceanddurationofgazefixations.Thedashedlinesindicate,attheirintersectionswiththegreyline,thecorrespondingpencillocations.Intheleftpanel,comparisonofthefixationdotswiththeircorrespondingpencillocationsshowstheeyeleadingthehandasthedrawingprogressesfromtoptobottomofthepage.Intherightpaneldashedlinesalsoindicatesegmentlimitswheredrawingwaspaused;inthisexamplethefulldrawnlinecontinuesbelowtheleveloftheoriginalandisnotshowninitsentirety–notethepositionofsegment13onthecopywhichcorrespondsapproximatelytothelocationoffixation11inthecentralpanel.Thedashedcircleontherightpanelgivesascaleforbothgazefixationlocations(diameter=2degrees)andfixationdurations(diameter=2seconds).Meandrawingtimefortheentirelinewas14.5sfortracingand8.0sforblindcopying.{Figure5.JPEG}Avisualcomparisonofthecopylinewiththeoriginallineshowsthatscaleand,toalesserextent,rotationoftheoverallimageonthepaperweremanifestlyincorrect.InthecaseofsubjectSS,thecopysizewassignificantlylarger,andtheoverallrotationwasoutbyafewdegreesanti-clockwise(Figure3right).TheProcrustesanalysissummarizedinTable1confirmstheseimpressionsforthewholegroup:scalingerrorswerelarge(mean18.6%)androtationerrorswerealsosubstantial(mean6.9%).Incontrast,shapeerrorswereverysmall(mean1.3%).Thescalingerrorsweresignificantlydifferentbetweenthesixcopyingtasks(testedwithaonewayrepeatedmeasureANOVAthatexcludedthetracingtask,F(2,25)=10.02,p<0.001)andscalingerrorsincreasedsystematicallyasoriginal-pictureseparationincreasedfrom8to15to30degrees(linearcontrastF(1,6)=6.55,p=0.043;Figure5)untiltheyreachedthehighestlevelintheblindtasks.Thescalingerrorsdidnotdifferacrossthe3blindconditions(F(2,10)=1.69,p=0.23).

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Largerthan1-to-1scalingerrorsdidinfactcharacterizeallblindcopyingtestsperformedhere:ofthe21blindexperimentsrecorded,16resultedinoverallbiggercopiesand5insmallerones.Inthefirstblind/occludedtest(B1)themeanscalingerrorforallsubjectswas25.4%andinthelastblind/occludedtest(B3)itwas15.7%.Thedropinscalingerrorbetweenthefirstlastblindtestcouldsuggestthatalearningprocesswastakingplace,althoughfurtherdedicatedtestswouldbeneededtoconfirmthisresult.Withthecurrentsample,thedifferencewasnotstatisticallysignificant(pairedsamplest-test,t(6)=1.42,p=0.21).However,inthecontextoftheblindandgaze-shifttestsdescribedinthepresentpaper,theimportantobservationconcernsthemagnitudeandsystematicnatureofthescalingerrorsthataccompaniedblinddrawingamongstourstudents.Incontrasttothesescalingerrors,rotationerrorsdidnotvarysignificantlyacrossthetasks(F(5,25)=1.17,p=0.3)whileshapeerrorswereverylowandalsodidnotvaryacrossall6tasks(F(5,25)=2.33,p=0.07).Directcopying(gaze-shiftcopying):Eye-handinteractiontestsandaccuracyIntheblindtestssubjectsdirectedtheirgazeonlytotheoriginal.Inthedirectcopyingtests,gazedirectionwasnotrestricted;allsubjectsadoptednaturallythegaze-shiftmodeofdrawingforwhichgazealternatedbetweentheoriginalandthecopy.Gaze-shiftingisbyfarthemostcommonstrategyusedwheneithercopyingordrawingfromlife.Asexplainedinaprevioussection,weusedtestswithdifferentoriginal-to-copyvisualangleseparationsof8o,15oand30o.EyehandinteractionpatternWithallsubjects,butinvaryingdegrees,drawingtookplaceduringbothoriginalandcopygazes,i.e.drawingwasalternatelyblindandsighted.TheblinddrawingratioB(thetimespentdrawingblindasaproportionofalldrawingtime)variedsubstantiallybetweensubjects.Forexample,inthe15otest,Bvariedfrom80%forsubjectSSto10%forCA,withameanvalueof46%overthe7subjects.Inotherwords,during46%ofthedrawingtimedrawingproceededblind.FixationsconstitutingeachgazewereorganizedintopatternsvaryingbetweenthetwoextremesshownbySSandCA(Figure4).SS’sgazecyclestartedwiththeidentificationofanoriginalsegment(heremadeupoftwosimplelinesatrightanglestoeachother)withthehelpofafixationsequence1-2-3duringwhichmostofthesegmentwasdrawnblind.Thecycleterminatedasgazeshiftedtofixation4onthecopyactingasposition-lockjustintimeforthehandtofinishthesegment1-3.Thenextcyclethenstartedwiththeoriginalfixationon5.Theentireeye-handinteractionwasbasedonaquasi-synchronizedpatternofeyemovementsandhandmovementspunctuatedbyasuccessionoffixationsontheoriginalfollowedbyaposition-lockfixationonthecopy.Ourassumptionisthatthefixationslocatedalongtheoriginallinewerepartofthevisualencodingandspatialreferencingofasimplesegmentofthatline;andthattheensuingposition-lockfixationonthecopyprovidedspatialreferencefortheendingofthatsegmentandthestartofthenextsegment.

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Figure4.Detailedfixationpathsforgaze-shiftcopyingat15ooriginaltocopyseparation.Theoriginallinesareontheleft,andthecopieddrawingontheright.Thenumberedcirclesizesindicatefixationlocationsanddurations–forclaritythesearenotfilledinthebottomrightpanel.Thedashedcircleontheupperpanelgivesascaleforgazefixationseparation(diameter=2degrees)andduration(2seconds).DrawingsfromsubjectsSSandCAareshown,representingthetwoextremesofbehaviourweobserved.Meandrawingtimefortheentirelinewas14.1sforSSand178.6sforCA.{Figure6.JPEG}

CAspentmuchmoretimelookingattheemergingcopythantheoriginal.Sheworkedalmostentirelysighted,notsegmentingbutusingtheoriginal’ssimpleline-by-simplelinestructure,oftensaccadingbackandforthseveraltimesforeachsimpleline.Consequently,hergazecount(thetotalnumberofgazeshiftsbetweenoriginalandcopy)wasfourtofivetimesthatofSS.Typically,aftergazeshiftedtothecopy,CA’shandpausedbeforestartingtodraw,contributingthustosomeverylongcopygazedurations.CApresentedtheextremecaseofeye-handinteractionthatweencounteredinalloureyetrackingteststodate.AmountofblinddrawingInapreviousstudyonthegaze-shiftstrategywehaveshownthatblinddrawingepisodesarebuiltintomostgaze-shiftdrawingsituationsinvariableamountsdependingonindividualsubjectsanddrawingtypes[14].BlindepisodesweresimilarlyobservedinthepresenttestswithblindratioBvaryingbetweenlowestvalues(12%subjectCA)tohighestvalues(80%subjectSS)(Table1).Inotherwords,intestsperformedwithusingthesameoriginals,CA’sdrawingswereessentiallysightedandSS’swerenotfarfromblind.DirectcopyingerrorsTable1showsthatthemeanerrorvaluesforallsubjectscalculatedoverthethreeoriginal-copyseparationswereinsignificantforshape(mean1.2%),smallforscale(mean4.0%)andsmallforrotation(mean4.4%).Changingoriginal–copyseparationsdidnotsignificantlyaltertheseresults.Thecorrespondingvaluesfortheblindtestshadbeen1.3%,18.6%and6.5%.Inotherwords,allowingasubjectvisionofthecopyavoidedmostofthescalingerrorswhichhadbeenintroducedwhilethesubjectwasdrawingblind.Incontrast,shapeerrorsremainedverylow,androtationerrorswereonlyslightlyhigher.

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Figure5.Comparingmeandrawingerrorsfor7subjectstracing,drawingblind(B1,B2,B3)andgaze-shiftdrawingatdifferentseparations(8o,15o,30o).Shapeerror=grey(leftbars);rotationerror-lightgrey;scaleerror=darkgrey(rightbars);errorbarsarestandarddeviations(1SD).{FigureB2_amended.eps}CONCLUSION:ABOUTRODIN’SBLINDSTRATEGYBytheendofthelastdecadeofthe19thcRodinhaddevelopedadrawingfromlifetechniquewherebyhedidnotlookatthepictureashewasdrawingit.Heproducedseveralthousanddrawingsinthisway,manyofexceptionaldynamicandpictorialqualityalthoughafewalsoexhibitedinstancesofmisplacedlines.Wefoundthatartstudentscouldalsocopyblind,withonlyinsignificant-to-smallshapeandrotationerrorsbutwithseverescalingerrors.Thesescalingerrorswouldnotappear,however,whenstudentsweretesteddrawinginthegaze-shiftmodewhichallowedvisionofthecopy.Basedontheresultsofaseriesofeyetrackerinvestigations[15],weproposedadrawinghypothesiswherebythedrawingofshapewastheresultofavisualtomotortransformationthatcouldbeexecuteddirectlywhileperceivingtheoriginal,andwithoutvisionofthehandorcopy;incontrast,correctspatialpositioningofthedrawnshapeonthecopy,includingthestartandendpositionsoflinesegments,requiredvisionofthedrawingsurfaceandemergingdrawing.Correctscalingbeingadirectconsequenceofspatialpositioningwasthereforenotpossiblewhendrawingblind.WithhisinstantdrawingsRodinhadevidentlydevelopedapersonaldrawingstrategytominimizeoreliminatealtogetherthescalingerrorfactor.FurtherinsightintowhatRodinwasattemptingcomesfromourpreviousfunctionalbrainimaging

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work,inwhichbrainactivationlevelsweremeasuredinnormal,non-expertdrawerswhowerechallengedwithvariousdrawingtasks.Inonestudy[16],thepatternofbrainactivationconfirmedprevioussuggestionsthatthevisualidentificationandextractionoffeaturesintheoriginalimageisguidedbytop-downdecisionsthatdependonfrontalcorticalareas,stronglyinfluencedbytheparticipant’spriorknowledgeoftheobjectbeingdrawn,forinstancewhendrawingafacecomparedtoanabstractshape.Rodin’scommentary[17]suggestshedeliberatelysoughttoavoidthis“technicalproblemofrepresentingonpaper”byusinghisinstantblinddrawingstrategy.Asecondbrainimagingstudy[18]showedthatwhenvisuallyencodingandsubsequentlydrawingaline-drawnface,wherethenon-expertswerepresentedwithfewifanydecisionsaboutwhattodraw,therewasapatternofbrainactivationconsistentwithadirectvisuomotormappingduringtheencodingphase,andnoevidenceforretentionandrecallofamentalimage.Thusevennon-expertartistshavethecapacitytodirectlytranslatevisualinputintomotoractions,butthisisnormallyoverlaidbytheirpriorknowledgeandjudgment,andasthispapershows,isliabletoleadtosubstantialerrorsinlocatingthedrawnsegmentsonthepaper.Rodinwasthereforeexceptionalinbothhisskillfulvisuomotoraccuracy,andhisdeliberateeliminationoftop-downjudgment. Rodin’scaseisuniqueinthesensethatwhendrawingblindhenotonlymasteredshapebutalsoscaling.Astudyofhisinstantdrawingsshowsthat,althoughheoccasionallymisplacedlines,asseenforFigures1and2,sucherrorswerequitedifferenttothesystematicscaledistortionsoccurringwithoursubjects.WesuggestthatRodin’smisplacementswereessentially‘one-off’consequencesoftheexceptionalspeedatwhichhewasdrawinghisfastmovingmodels.Acontemporaryartcriticwhoobservedhimatworknoted:“Inlessthanaminute,hehascapturedthissnapshotofmovement”[19].Asforthefrequentout-of-framehandsorfeet,wesuggestthattheysimplyindicatedhispreferenceforsmaller,easiertomanage,hand-helddrawingboardsevenifthismeantre-sketchingthemissingelementelsewhereonthepaper.AsmentionedbyN.Lehni,2009[20],forRodin,theimportancewasnottorenderaperfectstaticshapebuttorecordhisimmediateperceptionofadevelopingmovement,howeverimpetuousorephemeralthatmovementmightbe,andtosuccessfullycaptureagestureandattitudehithertounknowntothehistoryofart.ApartfromdrawingveryfastwealsoknowthatRodinwasdrawingwithoutinterruption.Ludoviciobserved:“ThenextthingInoticedisthatheseemedundersomeobligationnottolifthispencilfromthepaper,afterhavingoncebeguntodraw”[21].Seenindetail,Figure2suggeststhatthemisplacedlinespreviouslynotedwereconsequenttoanunscheduledliftingofthepencilwhiledrawingthemodel’sthigh.Whereasmostartistsslowdownorstopaltogetherbetweenconsecutivesegments[22],abehaviorwealsoobservedinthestudents’copyingtasks,Rodinmovedhishandvirtuallywithoutinterruptionfromthebeginningtotheendofadrawing.Inthiswaytheentirehumanfigurewasdrawninonerapidsweep,thusreducingtheopportunityofscalechangesoccurringbetweenthedifferentpartsofadrawing.Anotherrecurringfeatureconsistedoftheartistusingawavyline,asseen,forexample,withthemodel’sleftleginFigure6(seealsothemodel’sbackinFigure2).Thedarkerline,drawninasubsequentsightedsession,wasquiteobviously

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derivedfromthisinitialwavyline.WecanonlyguessatRodin’sintentions:wasthewavylineaquickwayofindicatingtheapproximatebandwithinwhichthetruelinewouldbedefinedduringthesubsequentredrawingstage?Whatappearstimeandagainwhenviewingtheinstantdrawingsisthattheartistwasdrawingthemovementofthebodyasopposedtodrawingtheindividualelementscomposingthatmovement.Forexample,inFigure1,thecontourlinesofthemodel’srightarmgreatlysimplifytheindividualelementsoftheshoulder,upperarm,lowerarmandhand,yetthebody'sflowingmovementfromnecktofingertipsisperfectlycaptured.Wemayspeculatethattheimpressionoffast-movingactionwouldhavebeenlosthadtheartistinterruptedhisvisionofthemodelinordertovisuallycontrolthedepictionofindividualshapes.Insteadofsegmentingthevisualsceneinfrontofhim,Rodinunifiesitintothecontinuousmovementofhishand.AsDominiqueViéville,scholarofRodin’sworktechniques,remarks“…Rodinbasedhispracticeontheintuitiveimpetustransmittedfromtheeyetothehand,excluding,apriori,allpreoccupationwiththeexecution”[23].Intheartist’sownwords:“Jesaispourquoimesdéssinsontcetteintensité.(…)C’estquejen’intervienspas.Entrelanatureetlepapier,j’aisuppriméletalent.Jeneraisonnepas,jemelaissefaire...”(“Iknowwhymydrawingshavesuchintensity…ItisbecauseIdon’tintervene.Betweennatureandthepaper,Ihaveeliminatedtalent.Idonotreason,Iletithappen”)[24].

Figure6.Thewavyinstantouterlineofthemodel’sleftleg,atthebottomofthedrawing,andthesubsequentlydrawndarkerright/correctline,illustrateRodin’sprocedure:heismoreinterestedintheoverallmovementthatcreatestheshapethanintheindividualbodyelement.Contrasthasbeenenhanced.{D.638_Lores.JPEG}

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Insummary,ouranalysisofRodin’stechnique,supplementedbyhisownwordsandthereportsofwitnessestohis“instantdrawing”isconsistentwiththeneuralprocesseswehaveinferredaboutvisuomotorbehavioursinsimplerdrawingandcopyingtasks.Theeyecancapturesegmentsofanobservedscene,ordrawing,ormodel,anddetailedcognitivedecisionscanbeimplementedtoallowcarefulselectionofhowtorepresenttheseonpaper[25].WhatstandsoutforRodinistheextraordinaryaccuracyofhisblinddrawingsintermsoftheirscaleandpositionofthedrawnshape.Inbothuntrainedparticipantsandtheartstudentswehavetested,scaleandpositionoftheunseendrawingarepronetosubstantialerrors.However,allsubjects,eventhosewithoutanyformaltrainingindrawingarecapableofcapturingandreproducingshapeaccurately.Thisdirectvisual-to-motortransformationmayinvolveminimalpriorknowledgeofwhatisbeingdrawn,andmayhaveallowedRodintoensurethat“nothingwoulddistractmefrommy…visual…understandingofthemodel”-aquotefromLudoviciinwhichwehaveinsertedthewordvisual[26].

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REFERENCES[1]N.Lehni,UneOeuvredansl’OeuvredeRodininRodin:LaSaisieduModèle(Paris:MuséeRodin,2011)p.21-35.[2]K.Nicolaides,TheNaturalWaytoDraw(London:SouvenirPressLtd.,2008,initialcopyright1941)p.9-20.[3]B.Edwards,DrawingontheRightSideoftheBrain(London:HarperCollins,1993,initialcopyright1979)p.84-86.[4]A.M.Ludovici,PersonalReminiscensesofAugusteRodin(Philadelphia:Lippincott,1926)p.138-139.[5]H.Pinet,“ComedyorCurtain-up:RodinandhisModels”inRodin,theFigureofEros(ParisMuséeRodin,2006)p.14.[6]]D.Viéville,“‘Eyes-off’Drawings”inRodin,TheFigureofEros(Paris:MuséeRodin,2006)p.31-55[7]Clément-Janin,“LesdessinsdeRodin,”LesMaitresdudessin(Paris,1903)p.285-287.[8]A.M.Ludovici(4)p.136.[9]J.TchalenkoandR.C.Miall,“Eye-handStrategiesinCopyingComplexLines,”CortexVol.45,368-376(2009).[10]D.G.Kendall,D.G.,1989.“Asurveyofthestatisticaltheoryofshape”,StatisticalScience,Vol.4(2),87–99(1989).[11]J.Tchalenko,Se-HoNam,M.LadangaandR.C.Miall,“TheGaze-ShiftStrategyinDrawing,”PsychologyofAesthetics,Creativity,andtheArtsVol.8,No3,330-339(2014).[12]J.J.Tchalenkoetal.(9)[13]R.C.Miall,E.GowanandJ.Tchalenko,“DrawingCartoonFaces:AFunctionalImagingStudyoftheCognitiveNeuroscienceofDrawing,”CortexVol.45,394-406(2009).[14]Tchalenkoetal.(9)[15]Tchalenkoetal.(9)[16]R.C.Mialletal.(13)[17]A.M.Ludovici(4)

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[18]R.C.Miall,Se-HoNamandJ.Tchalenko,“Theinfluenceofstimulusformatondrawing–afunctionalimagingstudyofdecisionmakinginportraitdrawing,”NeuroImage,Vol.102,608-619(2014).[19]Clément-Janin(7)[20]N.Lehni,“MatisseetRodin,unepassionpourledessin”inMatisseRodin,Paris(MuséeRodin,2009)[21]A.M.Ludovici(4)[22]J.Tchalenko,“Segmentationandaccuracyincopyinganddrawing:Expertsandbeginners,”VisionResearch,Vol.45,791-800(2009).[23]D.Viéville,Eyes-offDrawings,p.31-55,inRodin,TheFigureofEros(Paris:MuséeRodin,2006).[24]J.E.S.Jeanès,Rodin,p.146,inD’aprèsNature:SouvenirsetPortraits(Paris:Granvelle,1934).[25]J.J.Tchalenkoetal.(9)[26]A.M.Ludovici(4)

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GLOSSARYBlinddrawing:theactofcopyingordrawingwithoutlookingatone’shandorpaper.Blindratio(B):theamountofblinddrawingtimeasaproportionofalldrawingtime.Complexline:alinemadeupofseveralsimplelines.Copy:(verb)reproducinganoriginallineordrawing;(noun)theresultofcopying.Copygaze:gazedirectedtowardsthecopybeingproduced.DrawingratioD:theratioofactualdrawingtimeoccurringduringgazeontheoriginaltodrawingtimeoccurringduringgazeonthecopy.Fixation:themaintainingoftheeyessteadyonasinglelocation.Alsousedtoindicatethepointoffocusintimeandspaceduringwhichtimetheeyesarerelativelystable.fMRI:(functionalMagneticResonanceImaging)isaneuroimagingprocedureusingMRItechnologythatmeasuresbrainactivitybydetectingassociatedchangesinbloodflow.Fovealvision:visionusingthecentralportionoftheretinaresponsibleforsharpcentralvision.Gazeduration:thetimeduringwhichvisionisdirectedtowardaspecifiedregionofascene.Agazecanbemadeupofseveralneighboringconsecutivefixations.GazeratioG:theratiooforiginalgazedurationtocopygazeduration.Gaze-shift:redirectingthegazefromoriginaltocopyorviceversa.Misplacement:anerrorinlocatingadrawnlineonthepaper,withoutgrosserrorsintheshapeorscaleoftheline.Original:theexternalworldstimulus(objectorimage)thatisbeingcopiedordrawn.Originalgaze:gazedirectedtowardtheoriginalwhichisbeingcopiedordrawn.Picture:drawnorpaintedtwo-dimensionalartisticrepresentation.Position-lock:astableeyefixationactingasaspatialreferenceforthedrawinghand.Aposition-lockisgenerallylocatedintheimmediatevicinityofthesegmentbeingdrawn.Saccade:asmallrapidmovementoftheeyebetweentwofixations.Segment:asectionofacomplexlinecomprisingoneormoresimplelinesanddrawninasinglehandmovement.Segmenting:theactofsubdividingacomplexlineintosimplersegments.Sighteddrawing:theactofcopyingordrawingwhilelookingatone’shandorpaper.Simpleline:astraightoruniformlycurvedline.Target-lock:astableeyefixationactingasanendpointtargettowardswhichthehandisdrawing.Visuomotor:thementalprocessestransformingvisualinformationcapturedbytheeyeintomovementofthehand.