Bachelor Degree Project in Cognitive Science Three years Level 30 ECTS Spring term 2016 Sofia Fröjdman Supervisor: Tarja Susi Examiner: Niklas Torstensson

USER EXPERIENCE GUIDELINES FOR DESIGN OF VIRTUAL REALITY GRAPHICAL USER INTERFACES controlled by head orientation input

Abstract Withtherecentreleaseofhead-mounteddisplaysforconsumers,virtualrealityexperiencesaremoreaccessiblethanever.However,thereisstillashortageofresearchconcerninghowtodesignuserinterfacesinvirtualrealityforgoodexperiences.Thisthesisfocusesonwhataspectsshouldbeconsideredwhendesigningagraphicaluserinterfaceinvirtualreality-controlledbyheadorientationinput-foraqualitativeuserexperience.Theresearchhasincludedaheuristicevaluation,interviews,usabilitytests,andasurvey.Avirtualrealityprototypeofavideoondemandservicewasinvestigatedandservedastheapplicationfortheresearch.Findingsfromtheanalysisofthedatawereapplicationspecificpragmaticandhedonicgoalsoftheusers,relevanttothesubjectiveuserexperience,andcurrentuserexperienceproblemswiththeprototypetested.Incombinationwithpreviousrecommendations,theresultledtothedevelopmentofsevenguidelines.However,theseguidelinesareconsideredonlytoserveasafoundationforfutureresearchsincetheyneedtobevalidated.Newhead-mounteddisplaysandvirtualrealityapplicationsarereleasedeverydayandwiththeincreasingnumberofusers,therewillbeacontinuousneedformoreresearch.Keywords:Virtualrealitygraphicaluserinterface,Headorientationinput,Head-mounteddisplay,Userexperience,Videoondemandservice

Popular scientific abstract Asaresultoftherecentreleaseofhead-mounteddisplaysandvirtualrealitysets,suchasOculusRift,SamsungGearVR,andGoogleCardboard,virtualrealityhasturnedintoabigtechnologytrend.Sincethevirtualrealityexperiencesjustrecentlyhavebeguntobecomeavailableforconsumers,thereisstillalackofresearchconcerningtheusersexperienceofthem.Howshoulduserinterfacesbedesignedforvirtualrealitytobeeasyandfuntouseandhowshouldtheuserinterfacebecontrolledinthebestpossibleway?Thisthesisfocusesontheonlyavailablecontrolmethodthatispossibletousewithalldifferenthead-mounteddisplaysandvirtualrealitysets.Thewaytheuserwithahead-mounteddisplayturnhisorherheadindifferentdirections,allowtheusertoseemoreofthevirtualworld,andthiscouldalsobeusedtoprojectagazecursorinthecentreoftheuser’sfieldofview.Iftheuserthenstayswiththegazecursoroveracertainobjectintheuserinterfaceforapredeterminedperiodoftime,aselectioncanbemade.Thisthesisfocusesonansweringthequestionofwhataspectsshouldbeconsideredwhendesigningauserinterfaceinvirtualreality,controlledinthisway,forqualitativeuserexperiences.Aprototypeapplicationofavideoondemandserviceinvirtualrealitywasusedforpartoftheresearchandtestedbyusers.Additionally,userswereinterviewedandaskedinasurveyabouttheirgoals,knowledge,preferences,andexpectations.Theresultoftheresearchshowedthegoalsofwhyuserswantedtouseavideoondemandserviceinvirtualrealitywithahead-mounteddisplayandwhattheywantedtobeabletodoinsuchanapplication.Italsoshowedcurrentuserexperienceproblemswiththeapplicationthatwastested.Basedontheseresults,togetherwithpreviousrecommendationsfoundinliterature,newguidelinesweredeveloped.However,theseneedtobetestedandfurtherconfirmedbeforetheycanbeused.Withthereleaseofnewhead-mounteddisplaysandvirtualrealityapplicationseveryday,therewillbeagrowingnumberofuser,andthiswillleadtoanincreasingneedforresearchabouthowtoimprovetheexperiencesaswell.

Acknowledgements Writingthisthesishasbeenachallengingbutveryexcitingprocess.Moreover,ithasbeenatremendouslearningexperience,andIamverygratefulforalltheinspiringandsupportivepeoplearoundmewhohavehelpedmealongtheprocess.Foremost,IwouldliketoexpressmysinceregratitudetomysupervisorTarjaSusiforallthecontinuoussupportandguidanceduringthesemonths.IwouldalsoliketothankNiklasTorstenssonforhisfeedbackandencouragement.Moreover,IwouldliketothankpeopleatAccedoforwelcomingandsupportingmeaswellassharingtheirknowledge.IspecificallywanttothankmyAccedosupervisor,JoséSomolinos,whohasinspiredmeandintroducedmetotheworldofvirtualreality.Mysincerethanksalsogotoalltheparticipantsintheresearchwhohastakentheirtimetohelpme.Lastbutnotleast,Iwouldliketothankmyfamilyandfriendsfortheirnever-endingencouragementandsupport.

ContentsList of abbreviations ............................................................................................................................ 1 Introduction ..................................................................................................................................... 1 2 Background ..................................................................................................................................... 3

2.1 Virtual reality and related concepts ........................................................................................... 3 2.2 Virtual reality graphical user interface ...................................................................................... 5 2.3 Head-mounted display ............................................................................................................... 7 2.4 Head orientation input and head gaze ........................................................................................ 9 2.5 User experience ....................................................................................................................... 11 2.6 Video on demand service ......................................................................................................... 12 2.7 Research related design principles for virtual reality graphical user interfaces ...................... 13 2.8 Research aim and objective ..................................................................................................... 16

2.8.1 Expected contributions ..................................................................................................... 17 2.8.2 Limitations ........................................................................................................................ 17

3 Method ........................................................................................................................................... 18 3.1 Research design ....................................................................................................................... 18 3.2 Heuristic evaluation ................................................................................................................. 19 3.3 Interview .................................................................................................................................. 21 3.4 Usability test ............................................................................................................................ 22 3.5 Survey ...................................................................................................................................... 24

4 Procedure ....................................................................................................................................... 25 4.1 Accedo’s virtual reality video on demand prototype ............................................................... 25 4.2 Heuristic evaluation procedure ................................................................................................ 27 4.3 Interview and usability test procedure ..................................................................................... 28 4.4 Survey procedure ..................................................................................................................... 32

5 Result and analysis ....................................................................................................................... 34 5.1 Heuristic evaluation result and analysis .................................................................................. 35 5.2 Interview result and analysis ................................................................................................... 36 5.3 Usability test result and analysis .............................................................................................. 38 5.4 Survey result and analysis ....................................................................................................... 44 5.5 Comprehensive analysis .......................................................................................................... 47

5.5.1 Identifying the users’ goals, needs, behaviours, preferences, and context of use ............ 47 5.5.2 Analysis of the discovered user experience problems ...................................................... 48

6 Suggested guidelines ..................................................................................................................... 51 7 Conclusion and discussion ........................................................................................................... 56

7.1 Contributions and implications ................................................................................................ 56 7.2 Methodological discussion ...................................................................................................... 57 7.3 Future research ......................................................................................................................... 58 7.4 Concluding remarks ................................................................................................................. 58

References ............................................................................................................................................. Appendix A: Heuristic evaluation inspection questions ................................................................... Appendix B: Interview questions ....................................................................................................... Appendix C: Questions after usability test ........................................................................................ Appendix D: Survey design ................................................................................................................. Appendix E: Heuristic evaluation result ...........................................................................................

List of abbreviations 2D Two-dimensional2,5D Twoandahalf-dimensional3D Three-dimensional3DUI Three-dimensionaluserinterfaceAR AugmentedrealityDOF DegreesoffreedomFOR FieldofregardFOV FieldofviewGUI GraphicaluserinterfaceHMD Head-mounteddisplayUI UserinterfaceUX UserexperienceVE VirtualenvironmentVoD VideoondemandVR VirtualrealityVRGUI Virtualrealitygraphicaluserinterface

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1 Introduction Virtualreality(VR)waspredictedtobecomethebigtechnologytrendof2016(Cellan-Jones,2016).Afteralmost50yearsindevelopmentwherethetechnologyhasstruggledtomakethebreakthrough(Williams,2015),Perry(2016)claimsthat‘Thedoortomass-marketvirtualrealityisabouttoburstopen.’Duringtheyear,avarietyofhead-mounteddisplays(HMDs)forVRexperiences–includingOculusRift,Sony’sPlayStationVR,andtheHTCVive–willbereleased(Perry,2016;Cellan-Jones,2016).ConsideringmostHMDshasbarelybeenlaunched,thepublishedresearchaddressinggeneralusabilityandhowtheseHMDsaffectusersislimited(Serge&Moss,2015).User-centredresearchis,therefore,needed.Furthermore,O’Connell(2012)claimthatdesigningVRforagooduserexperience(UX)requiresnewwaysofthinkingaboutusabilityprinciples.WhenmorecommercialHMDsenterthemarket,thenumbersofVRapplicationsareexpectedtoincrease(Dorabjee,Bown,Sarkar&Tomitsch,2015).Onemainfactorforwhetheranapplicationwillsucceedornotistheuserinterface(UI)(Molina,González,Lozano,Montero&López-Jaquero,2003).WhiledecadesofresearchhavelaidthefoundationforthetechnologyofHMDs,therehasbeenalackoffocusontheUIs(Dorabjeeetal.,2015).Bowman(2013)claimsthattheprinciplesofgoodthree-dimensional(3D)UIdesignaremoreimportantthanevertounderstand.Comparedtoguidelinesforgraphicaluserinterfaces(GUI),thedesignprinciplesfor3DUIdesignarenotnearlyaswelldeveloped.ThedevelopmentofVRGUI(VRGUI)presentsuniquechallenges(OculusVR,2015a).Onedesignprinciplefor3Dinteractionistounderstandtheinteractiontechniquesavailable(Bowman,2013).Thereisanewworldofinteraction,andtherulesandguidelinesarechanging(Norman,2010).Systemcontrolfor3DUIsisinitsinfancyasaresearchtopic,andthereisalackofempiricalevidencefortheusabilityofvarioussystemcontroltechniques(Bowman,Kruijff,LaViola&Poupyrev,2004).DonNorman,oneofthemostinfluentialvoiceswithintheuserexperienceindustry,recentlysaid‘Aswestartmovingintovirtualreality(…)itisnotatallobvioushowyoucontrolthings’(Axbom&Royal-Lawson,2016).NotraditionalinputmethodisidealforVR(OculusVR,2015b).Innovationandresearchareneeded.InVR,fundamentalformsofinteractionaremovement,selection,manipulation,andscaling(Mine,1995).OneofthemaintechniquesusedinVRisdirectuserinteraction,whichcanbedefinedastheuseofgesturesandmovementsofheadandhandstospecifyinteractionparameters.However,themostintuitivewaytointeractwithaVRGUIaccordingtoOculusVR(2015a)isthroughgazetracking.Eyegazedirectioncanbeapproximatedusingtheorientationofauser’shead(Mine,1995).Ifacursorisplacedinthecentreofthedirectiontheuseriscurrentlyfacing,itcanprovidetheuserwiththeexperienceofcontrollingthesystemwithhisorhergazedirection(OculusVR,2015b).Tothebestoftheauthor’sknowledge,thisistheonlyinteractionandinputmethodthatiscurrentlycompatiblewithallHMDsandVRsetsusedwithsmartphoneswithouttheneedforanyexternalinputdevice.Oneofthemostwidelyresearchedfields,withinthefieldofhuman-computerinteraction,hasbeentheuseofeyegazeasaninputmodalitytocontrolsystems(Bazrafkan,Kar&Costache,2015).Eventhoughresearchershaveputmucheffortinthefield,theusabilityofeyegazeasaninputmodalityremainsmarginal(Bazrafkanetal.,2015).Equallyimportantis,thattothebestoftheauthor’sknowledge,theuseofeyegazedirectionapproximatedbyheadorientationasaninputmodalityhasbarelybeenresearched.Furthermore,thereisalackofacommonlyusedtermfortheinteractionmethodandtherefore,thesuggestedterm‘headgaze’isusedthroughoutthisthesis.

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WiththeintroductionofOculusRift,thegamingindustrybecameinterestedinVR(Dorabjeeetal.,2015).However,todayVRisbecomingintegratedacrossmanydifferentdomains,suchasmedical,trainingsimulations,andeducation.MarkZuckerbergrecentlysharedhisvisionforthefuturebysaying‘Whenyouthinkaboutvirtualreality,alotofpeoplefirstthinkaboutgaming.ButIactuallythinkvideoisgoingtobemoreengaginginalotofways’(Zuckerberg,2015).Yu,Zheng,ZhaoandZheng(2006)statethatthenextmajorstepintheevolutionofmediacontentdeliveryisstreamingvideoondemand(VoD)overtheInternet.VoDservicesallowuserstotakepartofanyvideocontentatanytimeandplace(Mustillo,Belanger,Fayad&Menzies,1997).However,fromtheuserperspective,usingaVoDservice,isnotaboutaccessingmanydifferentmovies,itisabouthavingaquieteveningwithaspouseorindulginginaTVshow(Goodman,Kuniavsky&Moed2012).Itisallabouttheexperience.AccedoisacompanythatdevelopsTVapplicationsolutionswiththemissiontodeliverattractiveandsuccessfulexperiencesacrossavarietyofconnectedvideodevices(Accedo,n.d.).TheyservedasaresearchpartnerduringthethesisandtheirdevelopedVoDserviceprototypeforVR-controlledbyheadorientationinput-wastestedinonepartoftheresearch.TheaimofthisthesisistocontributetotheunderstandingofwhataspectsshouldbeconsideredwhendesigningVRGUIs-controlledbyheadorientationinput-forqualitativeUX.Onecontributionfromtheresearchisthedefinitionoftheusers’pragmaticandhedonicgoalswhenusingaVoDserviceinVR.Furthermore,theusers’expectations,needs,behaviours,preferencesandpredictedcontextofusewereclarified.Inaddition,currentUXproblemsoftheprototypewerediscoveredandanalysed.However,themaincontributionissevenuniquedevelopedUXguidelines.Theyarebasedontheresearchresultandanalysisincombinationwithrecommendationsdiscoveredinthebackgroundliteraturereview.Nevertheless,theseareconsideredasaresearchfoundationsincetheyarenotvalidated,andmoreresearchisrequiredtoconfirmtherelevanceofthem.Whilethischapterservesasanintroductiontothethesis,Chapter2definesanddiscussesthedifferentcoreconceptsofVR,VRGUIs,HMDs,headorientationinputandheadgaze,UX,andVoDservices.Furthermore,itpresentsexistingdesignprinciplesrelatedtotheresearchandtheresearchaim,anobjective,expectedcontributions,andlimitations.Chapter3describestheresearchdesignandthefourmethodsthatwereusedincludingaheuristicevaluation,interviews,usabilitytests,andasurvey.TheprocedureoftheusedmethodsispresentedinChapter4togetherwithadescriptionofAccedo’sVoDserviceprototypeforVR,whichwasusedfortheheuristicevaluationandtheusabilitytests.Chapter5presenttheresultandanalysisoftheresearchmethodsseparatelyandcomprehensively.ThedevelopedguidelinesarepresentedanddescribedinChapter6.Finally,Chapter7coversconclusions,contributions,amethodologicaldiscussion,andfutureresearch.

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2 Background Thischapteraimstodefineandinformaboutthecoreconceptsinthethesisandpresentpreviousrelatedresearch.Asaresultoftherecentcommercializationofhead-mounteddisplaysandvirtualrealityforconsumers,anumberofthesourcesusedintheliteraturereviewarebasedonwebsites,blogs,andvideocontent.Thereisashortageofpublishedandpeer-reviewedresearchwithinthefield.Thefirstsectionofthebackgroundchapterdefinesvirtualrealityanddescribessynonymsandrelatedconcepts.Section2.2definevirtualrealitygraphicaluserinterfacesandexplainimportantfactorsandconceptsrelatedtoit.ThethirdSectionpresentsthehead-mounteddisplayanditscharacteristicsanddisadvantages.Section2.4focusesonheadorientationinputandthesuggestedtermheadgazefortheinteractionmethod.Thereafter,thetermuserexperienceisexplainedandinSection2.5.Section2.6coversanddescribesvideoondemandservices.InSection2.7,existingdesignguidelinesfor3Dinteractionandvirtualrealitygraphicaluserinterfacesaredescribed.Thefinalsection,Section8,definestheresearchquestion,aim,objective,expectedcontributions,andlimitations.

2.1 Virtual reality and related concepts

Manydifferentdefinitionsofvirtualreality(VR)havebeenusedovertime.In1993,Adam(1993)definedVRas‘acombinationofvariousinterfacetechnologiesthatenablesausertointuitivelyinteractwithanimmersiveanddynamiccomputer-generatedenvironment’.Acoupleofyearslater,thedefinitionwassimplifiedanddescribedVRasaninteractive,three-dimensionalcomputer-synthesizedenvironment(Pratt,Zyda&Keller,1995;Barfield&Furness,1995).Brooks(1999)decidedtofocusontheimmersioninthedefinitionthatclaimedVRexperiencestobeanyinwhichtheuseriseffectivelyimmersedinaresponsivevirtualworld.Yearslater,VRwasseenasamediuminShermanandCraig’s(2003)definition.TheystatedthatVRis‘amediumcomposedofinteractivecomputersimulationsthatsensetheparticipant’spositionandactionsandreplaceoraugmentthefeedbacktooneormoresenses,givingthefeelingofbeingmentallyimmersedorpresentinthesimulation(avirtualworld).’AtthesametimeBowman,Kruijiff,LaViola,andPoupyrev(2004)emphasizedonhowtheVRisseenandcontrolledintheirdefinitionthatVRissomethingseenfromafirst-personpointofviewthatisalsocontrolledbytheuserinrealtime.InShermanandCraig’s(2003)definitionofaVRexperience,theydescribefourkeyelements.Theseareavirtualworld,sensoryfeedbackasaresponsetotheusers’input,interactivity,andimmersion.AvirtualworldisthecontentofagivenmediumbutcanalsobeusedasasynonymforVR.EssentialtoVRisthesensoryfeedback,whichmeansthatthesystemgivestheusersfeedbackbasedontheirphysicalposition.FortheVRtoseemauthentic,itshouldbeinteractiveandrespondtotheusersactions.Thelastkeyelementisphysicalimmersion.Physicalimmersionisdefinedasthefeelingof‘bodilyenteringintoamedium…’(Sherman&Craig,2003).Thiswhileimmersioncanbedescribedasthefeelingofbeingdeeplyengaged(Coomans&Timmermans,1997).Theconceptof‘beingimmersed’isoftendescribedbymedia,andgenerallyreferstoafeelingofbeinginvolvedinanexperience(Sherman&Craig,2003).TheVRcommunityisalsousingthetermpresencetopresentthesameconcept.Users’senseofcopresenceandunderstandingoftheenvironmentareaffectedbythelevelofimmersiontheyareexperiencing(Bowman,Coquillart,Froehlich,Hirose,Kitamura,Kiyokawa&Stuerzlinger,2008).VRhasmanysynonymsandalsorelatetoseveralotherconcepts.ThetermvirtualrealitywasoriginallycoinedbyJaronLanier(Lanier&Biocca,1992;Machover&Tice,1994;Krueger,1991;

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Biocca&Lewy,1995).Beforetheexpressionbecamepopular,earlierexperimenters,suchastheVRpioneerMyronKrueger,usedthetermartificialreality(Machover&Tice,1994;Biocca&Levy,1995;Wexelblat,1995).Krueger(1991)definedartificialrealityasarealitythat‘…perceivesaparticipant’sactionintermsofthebody’srelationshiptoagraphicworldandgeneratesresponsesthatmaintaintheillusionthathisorheractionsaretakingplacewithinthatworld’.NowadaysartificialrealitycoincideswithwhatisgenerallyreferredtoasVR(Sherman&Craig,2003).HistoricaldefinitionsoftendescribedVRinthetermsoftechnologicalhardwarebutSteuer(1992)discussedaneedforanewdefinitionbasedontheconceptsofpresenceandtelepresencetomovepastthat.Aspreviouslydescribed,presencecanbeusedsynonymouslywithimmersionandtelepresencecanbedefinedas‘theabilitytodirectlyinteract(…)withaphysicalreal,remoteenvironmentfromthefirst-personpointofview…’(Sherman&Craig,2003).TelepresenceisalsoatermthatcanbesynonymouslyusedwithVR(Ashline&Lai,1995).Anothercommonlyusedtermisvirtualenvironments(VE)(Sherman&Craig,2003).BarfieldandFurness(1995)defineVEas‘…therepresentationofacomputermodelordatabasewhichcanbeinteractivelyexperiencedandmanipulatedbythevirtualenvironmentparticipant(s)’.AccordingtoShermanandCraig(2003)therearetwodefinitionsofVE,onedescribingitasavirtualworldandtheotherdescribingitas‘…aninstanceofavirtualworldpresentedinaninteractivemediumsuchasvirtualreality’.VEisalsooftenusedsynonymouslywithVR(Bowmanetal.,2004;Earnshaw,Gigante&Jones,1993;Sherman&Craig,2003).SomeresearchersprefertousethetermVEoverVR,sincethehypeoverVRhaveledtounrealisticexpectationsbeingassociatedtoit(Bowmanetal.,2004;Earnshawetal.,1993).CyberspaceisanothersynonymouslyusedtermforVR(Ashline&Lai,1995).WilliamGibsoncoinedtheterminhissciencefictionnovelNeuromancerthatwaspublished1984(Machover&Tice,1994).IfthetermisnotusedsynonymouslywithVR,cyberspacecanbedefinedas‘alocationthatexistsonlyinthemindsoftheparticipants,oftenasaresultoftechnologythatenablesgeographicallydistantpeopletointeractivelycommunicate’(Sherman&Craig,2003).RelatedtoVRisaugmentedreality(AR).ARenhancestherealworldbycomputer-generatedoverlays(Adam,1993;ShermanandCraig,2003).Zhou,Dun,andBillinghurst(2008)defineARasatechnology,whichallowscomputer-generatedvirtualimagerytoexactlyoverlayphysicalobjectsin

Figure1.Anoverviewofthekeyconcepts,synonyms,andrelatedtermstovirtualrealitydescribedthroughoutSection2.1.

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realtime.Whilesomedefinitionsaredependentoncertaintechnology,Azuma(1997)statethatARisanysystemthatcombinesrealandvirtual,isinteractiveinrealtimeandisregisteredinthreedimensions.SimilarlytoARismixedreality(Bowmanetal.,2004).ItcanbedefinedasacontinuumincludingbothVRandAR.Toconclude,variousdefinitionsofVRoftenhaveseveralsimilaritiesbutfocusondifferentcomponents.Adam(1993)describesVRinwordsoftechnology,andBrooks(1999)focusontheimmersivefeelingwhileShermanandCraig(2003)definesVRasamedium.ThedefinitionusedforthisthesisisthatVRisaninteractive,three-dimensionalcomputer-synthesizedenvironment(Prattetal.,1995;Barfield&Furness,1995)seenfromthefirst-personpointofviewandcontrolledinrealtimebytheuser(Bowmanetal.,2004).Furthermore,itisextendedtoincludeShermanandCraig’s(2003)fourkeyelements.Figure1providesanoverviewofthekeyconcepts,synonyms,andrelatedconceptstoVRdescribedthroughoutthesection.NextsectionwilldefineandfocusongraphicaluserinterfacesinVR.Itwillpresentdifferentcontentdisplaytechniques,challenges,andsolutions.

2.2 Virtual reality graphical user interface

Theuserinterface(UI)isthepartofacomputeranditssoftwarethatpeoplecansee,listento,talktoorinanyotherwayunderstandanddirect(Galitz,2007).Inover20years,thegraphicalUI(GUI)hasdominatedthewaypeopleinteractwithcomputers(Harper,Rodden,Rogers&Sellen,2008;vanDam,1997).Furthermore,ithasbeenastandardsincethe1990swhenApplefirstintroducedMacintosh(Butow,2007).ThestandardcomponentsofGUIsarecalledwidgets(Hartson&Pyla,2012).Theyincludeforexamplewindows,buttons,menus,toolbars,andscrollbars(Butow,2007).Basedonwidgets,andcommonlyassociatedwithGUIs,istheacronymWIMP,whichstandsforwindows,icons,menus,andpointingdevices(Molinaetal.,2003).ManyGUIsarealsodesignedfollowingthedesktopmetaphor.Themetaphorwasoriginallydevelopedtomaketheinteractioneasierforuserswhenthefirstpersonalcomputerarrived(Hartson&Pyla,2012).Itiscreatedbasedontheusers’existingknowledgeabouttheirowndesktopenvironmentsandtheobjectsusedaroundthemandappliesthesameconceptwiththesamefunctionalityintheGUI.Themetaphorisanexampleofhowtheinteractioncanbesimplifiedwithcognitiveaffordance(definedinSection2.5).A3DUI(3DUI)isdefinedasaUIthatinvolves3D-interaction(Bowmanetal.,2008).Researchwithin3DUIshastraditionallybeencloselyconnectedtoVR.Animportantpartof3DUIsisdepthinformation,whichhelpsuserstointeractwiththeapplication.Depthcanbevisualisedinvariouswayswiththehelpofdifferentkindofcues.Thesecanbedividedintofourcategories(Bowmanetal.,2004).Thefirstcategoryismonocular,staticdepthcues.Theyaredepthinformationthatcanbeviewedfromastaticimagebyasingleeye(Bowmanetal,2004).Moreover,theyarealsoreferredtoaspictorialcuesandincludeocclusion,linearandaerialperspective,shadowsandlighting,texture,gradients,relativesizeandheightrelativetothehorizon.Thesecondcategoryisoculomotorcues.Theyderivefrommusculartensionintheviewer’svisualsystem,describedasaccommodationandconvergence(Bowmanetal,2004).Thirdlymotionparallaxiswhatcausesobjectsclosetotheviewertomovemorequicklyacrossthevisualfieldthanobjectsfurtherawayfromtheviewer.Thelastcategoryisbinoculardisparityandstereopsis.Binoculardisparityreferstothedifferencebetweenthetwoimagesthateacheyeseesatthesametime.Thiswhilestereopsisistheeffectthatoccurswhenthesetwoimagesfuseintoonesinglestereoscopicimageprovidingadepthcue(Bowmanetal,2004).

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OnecommonapproachtodenotehierarchyinaGUIiswiththeuseofsize,contrast,andcolour(Sundström,2015).WhilethesetoolsarestillavailableinVR,theyareuseddifferently.Forexample,sizeisbasedonthedistancebetweentheuserandthepieceofcontent.Furthermore,contentcanbedisplayedinvariousways.Threedifferentcontentdisplaytechniquesarethe‘head-updisplay’,keepingthecontentlockedtotheenvironmentonanobjectorfloatingfree(seeFigure2).The‘heads-updisplay’locksthecontentatasetdistancefromtheviewer.Thisdisplaytechniquefollowstheuserifs/hedecidestoturnaroundormoveinthevirtualenvironment,keepingthecontentconstantlyfacingtowardstheuseratthesetdistance.Whenthecontentislockedtotheenvironment,thecontentstaysinthesamelocationwhentheusermoves,allowingtheusertoexploreitfromdifferentangles.Moreover,thecontentcanbelockedtoanobjectorfloatfree(Sundström,2015).Sundström(2015)describehowdesignersaretryingtoforcetwo-dimensional(2D)solutionsintoa3Dspaceeventhoughtheyhaveafullfieldofvisiontodesignin.However,heclaimsonereasontouse2Din3Distofacilitatefortheuser’ssmallconeoffocus(furtherdescribedinSection2.3)whentheyareusingaVRset,atypeofhead-mounteddisplay,toexperienceVR.Furthermore,asolutiontothesmallconeoffocusistouseacommontilemenu.Variationsintilemenusincludeiftheyareflat,curvedorsurroundingtheuser(seeFigure3).Aflattilemenulookslikeawalltotheuser.Thissolutionmakesitdifficulttoreadtextorseeimagesinperspective.Thecurvedtilemenuplacesthetilesfacedtowardstheuser,makingiteasiertoreadtextandviewimages.However,accordingtoSundström(2015),thebestsolutionistocreateasurroundedtilemenuwherethemenuisplacedaroundtheuserinthevirtualenvironment.Furtherrecommendationsincludekeepingthemenucontentlimitedandplacingcontentoflessimportancepushedoutofimmediateview,andthesmallconeoffocus,butstillaccessible.

Figure2.Threedifferentcontentdisplaytechniquesforvirtualreality.Thefirstfromtheleftisplacingthecontentasa‘heads-updisplay’,whilethefollowingvisualisethecontentlockedtotheenvironmentonanobjectorfloatingfree(afterSundström,2015).

Figure3.Threedifferenttypesoftilemenusforvirtualreality(afterSundström,2015).

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ThenextsectionwilldescribethetechnologyusedtoexperienceVR.Thehead-mounteddisplayisdefinedandimportantcharacteristicsarefurtherdescribed,includingpossibilitiesandlimitationsofthetechnology.

2.3 Head-mounted display

AVRsystemconsistsofadisplay,atrackingdevice,acomputerimagegenerator,athree-dimensionaldatabase,andapplicationsoftware(Adam,1993).Moreover,differentdisplaysareavailabletosuitdifferenttasksandexperiences.Thedisplayscan,forexample,beCAVE-like(caveautomaticvirtualenvironment)surroundprojectors,panoramicdisplays,workbenchprojectors,ordesktopdisplays(Brooks,1999).However,thedisplaydevelopedforandprovidingthegreatestsenseofimmersionisthehead-mounteddisplay(HMD)(Coomans&Timmermans,1997;Adam,1993).HMDsarewearabledevicesintheformofgoggles(Dorabjee,etal.,2015)thatblocksoutthevisionofthephysicalworldandprojectscomputer-generatedstereoscopicimagesontotwodisplayscreensclosetotheuser’seyes(Kavakli&Jayarathna,2005).AdvancesinhardwaretechnologyhaverecentlyledtotheproductionofHMDsforconsumers,suchastheOculusRift,whichissuitablefortheuseofimmersiveVRapplicationsincludinggaming,simulation,andfilm(Carnegie&Rhee,2015).Varioustermsareusedforthetechnology.OculusRiftisreferredtoasanHMD(Serge&Moss,2015)whileGoogleCardboardandSamsungGearVRaretwoexamplesofso-calledVRsets(Sundström,2015).WhileGoogle(2016)andSundström(2015)refertotheseasVRsets,otherauthors,suchasLamkin(2016),usethetermVRheadsetsforbothHMDsandVRsets.Furthermore,OculusVR(2015a)referstoGearVRasaVRheadsetandnotaVRset.Thevirtualrealitysociety(2016)claimthatthetermsVRheadsetsandVRglassesaresimplysynonymstoHMDsandthatiftheHMDattachstraighttotheusersheadandpresentvisualsdirectlytotheuserseyesitcouldbeconsideredanHMDinthebroadestsense.Therefore,thisthesiswillusethetermHMDforallvariationsincludingVRsets,VRheadsets,andVRglasses(seeFigure4forthreeexamplesofdifferentHMDS).DifferentHMDsusespowerfromdifferenttechnologies.WhileOculusRiftplugsintoacomputer,SonyPlayStationVRneedstobeconnectedwithaPlayStation(Lamkin,2016).Furthermore,SamsungGearVRandGoogleCardboardusesmartphonesastheirprocessorsanddisplays.Thesmartphones’gyroscopicsensorsandpositioningsystemsareusedtoaccuratelytracktheusers’headmovements.Whendescribingvisualdisplaydevices,suchasHMDs,importantcharacteristicsincludethefieldofregard(FOR)andfieldofview(FOV)(Bowmanetal,2004).FORreferstotheamountofthephysicalspacesurroundingtheuser.Itcanalsobeexplainedasthemaximumnumberofdegreesofvisualanglethatcanbeseeninstantaneouslyonadisplay.Itismeasuredindegreesofthevisualangle,soifacylindricaldisplaywerebuiltwheretheusercouldstandinthemiddle,thedisplaywouldhavea360-degreehorizontalFOR.TheFOVmustbelessthanorequaltothemaximumFOVofthehuman

Figure4.Examplesofthreedifferenthead-mounteddisplays.OculusRiftdeveloperkit2totheleft,GoogleCardboardusedwithasmartphoneinthemiddleandHomidousedwithasmartphonetotheright.

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visualsystem,whichisapproximately200degrees.HMDsusuallyhaveasmallFOVbutalargeFOR.AlowerFOVmaydecreaseimmersionandresultsin‘tunnelvision’whilehigherFOVcandecreasetheresolutionandintroducedistortion(Bowman,Datey,Ryu,Farooq&Vasnaik,2002).InHMDs,theFOVisabout94degrees(OculusVR,2015c).However,userscanchangetheorientationoftheirheadstoseemoreoftheirsurroundings.Chu(2014)describeshowtheheadorientationcanbechangedcomfortablyandtopmost.Peoplecanrotatetheirheadstotheleftabout30degreesinacomfortablemanner.Topmost,theycanrotatetheirheads55degreestotheleft.Thesamedegreesapplytowhenpeoplearerotatingtheirheadstotherightaswell.Furthermore,peoplecancomfortablyturntheirheads20degreesup,while60degreesisthetopmost.Moreover,peoplecanturntheirheadswiththechindown.While12degreesiscomfortable,thetopmostis40degrees.Thesedegrees,suggestedbyChu(2014)arevisualisedbyMikeAlger(2015a)(seeFigure5).WhenthesedegreesarecombinedwiththeFOVinanHMD,itcreates77degreestotherightandtotheleftofthecentrewheretheuserscanseeobjectscomfortablyandabout102degrees,totherightandtotheleftofthecentre,wheretheuserscanseeobjectsinamorestrainedway(Alger,2015a).AnotherimportantaspectofhowobjectsshouldbeplacedinvirtualenvironmentsexperiencedwithHMDsconcernthesenseofdepth.Chu(2014)claimsthatthestereoscopiceffectwillbelostifobjectsareplacedfurtherthan20metresawayfromtheuser.Moreimportantly,ifobjectsareplacedtooclosetotheuser,itwillcausecross-eyesanddoublevision.Toavoidstrainingtheusers’eyes,objectsshouldnotbeplacedcloserthanadistanceof75centimetresfromtheuser(OculusVR,

2015b).MikeAlger(2015a)hasusedtheserecommendations,butanotherrecommendationconsideringtheminimumdistanceclaimingittobe50centimetres,anddesignedfiguresillustratingwheretheobjectscanbeseencomfortablyandmeaningfullyandwherehethinksthemaincontentshouldbedisplayed(seeFigure6).

Figure5.FiguresdesignedbyMikeAlger(2015a)showingthedegreespeopleareabletoturntheirheads,comfortablyandtopmostfollowingChu’s(2014)recommendations.UsedwithpermissionofMikeAlger.

Figure6.MikeAlger’s(2015a)visualisationofhumansviewandareathatshouldbeusedfordesignswithinimmersivevirtualreality.Twodifferentfiguresinhisvideoshavebeencombinedinthisfigure.UsedwithpermissionofMikeAlger.

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However,thereisadifferencebetweengeneralcontentandaGUI.Lubosetal.(2014)suggestthat3Dselectiontasksthatrequirehighprecisionshouldbeplacedclosetotheuserseyes.Moreover,OculusVR(2015a)statesthattheidealdistancetoplaceaUIinVRisbetween1to3metersawayfromtheuser.Otherimportantcharacteristicsofvisualdisplaydevicesincludethespatialresolution(Bowmanetal,2004).Thespatialresolutionisameasureofvisualqualityrelatedtopixelsizes.Itisoftenmeasuredasdotsperinchbutisalsoaffectedbythescreensizeandthedistancebetweentheuserandthevisualdisplay.InsideanHMDasforexampletheGoogleCardboardorGearVRasinglescreenofasmartphoneissplitintotwo,oneforeacheye,dividingtheresolution(Sundström,2015).Moreover,theuserfocusesonthecentreofthisareaandcreatesacone-of-focusthatquicklyfall-offtowardsblurriness.Thisleadstoasmalllow-resolutionareatodesignfor(Sundström,2015).Furthercharacteristicsofvisualdisplaydevicesincludescreengeometry,lighttransfermechanism,refreshrate,andergonomics(Bowmanetal,2004).Thescreengeometryisrelatedtotheshapeofthescreen.Visualdisplayscanberectangular,L-shaped,hemispherical,orhybrids.Moreover,thelighttransfermechanismdecideshowthelightistransferredontothedisplaysurface(Bowmanetal,2004).Lightcanbefrontprojected,rearprojected,orasalaserlightdirectlyprojectedontotheretina.Thisisofimportancesincedifferenttypesof3DUIinteractiontechniquesareapplicablefordifferentlighttransfermethods.Therefreshratedescribesinwhichspeedthevisualdisplaydevicerefreshesthedisplayedimage.Thisisusuallymeasuredinhertzasrefreshespersecond.Finally,ergonomicscoverhowcomfortablethevisualdisplaydeviceistouse.Bowmanetal.(2004)emphasizethatcomfortisespeciallyimportantforvisualdisplaydevicessuchasHMDs.TypicaldisadvantagesofHMDsincludesystemlatency,limitedFOV,peripheralvision,andergonomicdiscomfort(Bowmanetal.,2008).WhendisplayingVRwiththeuseofanHMD,oneofthemostconcerningaspectsisthecommonexperienceofsimulatorsickness(SS)(Serge&Moss,2015).Itcancausephysicalreactionssuchasheadaches,nausea,dizziness,andeyestrain(Carnegie&Rhee,2015).Thisusuallygeneratesnegativeexperiencesandcouldleadtoconfusionorevenfainting(Moss&Muth,2011).Inthefollowingsection,inputdevicesandinteractionmethodsforVRexperiencedwithHMDsarefurtherexplained.Moreover,itfocusesontheheadorientationinputandthesuggestedtermheadgaze.

2.4 Head orientation input and head gaze

TheUIiscomposedofinputandoutput(Galitz,2007).Inputisthetechniquethatpeopleusetocommunicatetheirneedsanddesiredactionstothecomputerwhiletheoutputishowthecomputermediatestheresultoftheusers’directives.Aninteractionmethodcanbedefinedashowapersonusesaninputoroutputdevicetoperformataskinahuman-computerdialog(Foley,VanDam,Feiner&Hughes,1990).ThreemaintechniquesthatareusedinVRarephysicalcontrols,virtualcontrols,anddirectuserinteraction.Physicalcontrolsaretheuseofforexamplebuttons,sliders,andsteeringwheelswhilevirtualcontrolsarecontroldevicespresentedasvirtualobjects.Directuserinteractioncanbedefinedastheuseofgesturesandmovementsofheadandhandstospecifyinteractionparameters(Mine,1995).FundamentalformsofinteractioninVRincludemovements,selections,manipulations,andscaling(Mine,1995).OneconcernwithinteractioninVRisthatthereal-worldmetaphordoesnotallowefficientlarge-scaleplacementofobjectsinthevirtualenvironment(Bowman&Hodges,1997).Techniquesdevelopedtosolvethisandgrabaswellasmanipulateremoteobjectsareforexamplearm-extensiontechniquesandray-castingtechniques.Oneexampleofanarm-extendingtechniqueisthe

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Go-Gointeractiontechnique(Poupyrev,Billinghurst,Weghorst&Ichikawa,1996).Ray-castingisaninteractiontechniquethatusesavirtuallightray,specifiedbytheuser’shand,topointandgrabobjects(Mine,1995).Anotherconcernisthatinteractionin3Dmid-airisphysicallydemandingandoftencanhinderusersatisfactionandperformance(Chan,Kao,Chen,Lee,Hsu&Hung,2010).VRselectionproblemscanoftenbeefficientlysolvedwithpointingtechniques(Lubos,Bruder&Steinicke,2014).However,theyrequirealevelofabstractionthatispotentiallylessnaturalcomparedtothevirtualhandmetaphor(Lubos,Bruder&Steinicke,2014).Nevertheless,directinteractionleadstohigherperformancethanmanipulationofobjectsatadistance(Mine,Brooks&Sequin,1997).Incomputergraphicssystems,motiontrackerscanbeusedforfiveprimarypurposes(Welch&Foxlin,2002).Thefirstuseisfortheusersviewcontrol,whichmeansthatitprovidestheuserswithpositionandorientationcontrolandsimulatesafirst-personviewpointforpeopleusingHMDs.Secondly,motiontrackerscanbeusedfornavigation.Athirdwaytousemotiontrackersisforobjectselectionandmanipulation.Finally,motiontrackingcanbeusedforinstrumenttrackingandavataranimation.Trackingerrorscancontributetodestroyingthesenseofperceptualstability,causingsicknessordegradingtaskperformance(Welch&Foxlin,2002).OculusVR(2015b)claimsthatgazetrackingisoneofthemostintuitivewaystointeractwithaVRGUI.Theorientationoftheusers’headscanbeusedtoapproximatetheusers’gazedirection(Mine,1995;Mineetal.,1997).ThiscanbesimulatedtotheusersbyplacingacursorfloatinginthemiddleoftheirFOVs(Mine,1995).Thecursoristhencentredinthedirectiontheusersarecurrentlyfacing,givingtheuserstheexperienceofcontrollingthesystemwiththeirgazedirection.Thiscreatesanintuitivewaytoselectanitembysimplylookingatit(Mineetal.,1997).UserscaninteractwithaVRGUIthroughthismethodasifitwasamouseoratouchdevice(OculusVR,2015b).Tomakeaselection,theusers‘look‘,butactuallyturntheirheads,towardsanobject.Theselectionisthenindicatedwithastandardselectionsignal.Dwelltimeisatechniquethatcanbeusedtoselectoneobjectamongseveraldisplayed(Jacob,1991;Lankford,2000).Thismeansthatwhenausercontinuestolookatanobjectforacertainpredeterminedtime,theobjectwillbeselected.Alongdwelltimewilldecreasetheamountofunintendedselectionsthataremade,butitwillalsoreducetheresponsivenessoftheUI.Jacob(1991)claimsthatiftheresultofselectingthewrongobjectcaneasilybeundone,thenashorterdwelltimecanbeused.Forthisapproach,adwelltimeof150-250millisecondscanbeusedwithgoodresults.Thisprovidestheuserswiththesubjectivefeelingofahighlyresponsivesystem.Alongerdwelltime,over¾second,isneverusefulbecauseitisnotnaturalforeyestofixateononespotforthatlongandtheusercanalsosuspectthatthesystemhascrashed.Agooduseoftheobjectselectioninteractionistorequestfurtherdetailsaboutanobject.ThedetailsshouldbedisplayedonaseparateareawheresuchinformationisalwaysdisplayedintheUI(Jacob,1991).Themethodofusingheadorientationinputtoestimatetheusers’gazedirectionandplaceacursorinthecentreoftheusers’FOVisreferredtoasray-castingbyOculusVR(2015b).However,thisstandsincontrasttothepreviouslydescribeddefinitioninthissectionbyMine(1995)whoclaimsthatray-castingistheuseofavirtuallightray.Withregardtotheconflictingdefinitions,thetermray-castingwasnotusedasanameforthemethodinthisthesis.Mine(1996)usesthename‘look-atmenusinteractiontechnique’forthetechnique,buthealsoincludestheuseofanexternalinputdeviceintheinteraction.Furthermore,Mine’ssuggestednamehasnotbeenusedorpublishedbyotherresearchersandtherefore,willnotbeusedinthisthesiseither.Tothebestoftheauthor’sknowledge,thereisnocommonlyusedtermforthisinteractionmethodandtherefore,thesuggestedterm‘headgaze’willbeusedthroughoutthisthesis.

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KeyissuesineyetrackinginVRinvolvetheMidastouchproblemandgaze-pointtrackerinaccuraciesleadingtoincorrectactionsandselection(Bazrafkanetal.,2015).TheMidastouchproblemrelatetopeoples’eyemovementsthatarefrequentlyunintentional,whichmakesitproblematictousethemasaninputmodalitytocontrolasystem(Jacob,1991).Todevelopausefuleye-trackinginterface,theMidastouchproblemneedstobeavoided(Jacob&Karn,2003).Anotherproblemwithlimitingtheusers’eyemovementsisthatitwillalsolimittheusers’spatialdegreesoffreedom(DOF)(Carnegie&Rhee,2015).However,whenusingtheheadgazeinteraction,themovementwilloccurthroughheadorientationratherthaneyemovements,whichcompensatesforthisdrawback.AchallengewithusinggazeisthattheuserisalwayslookingatthedisplayedcontentbutmaynotalwayslookattheVRGUI(OculusVR,2015a).Becauseofthis,theusercan‘lose’theUIandnotrealizeitisstillavailable,whichcanresultinconfusionwhentheapplicationdoesnothandletheinputthewaytheuserexpects.ThisproblemcanbesolvedbymakingtheUIclosewhentheusergoesoutsidesomeFOVorbyautomaticallydraggingtheinterfacewiththeviewastheuserturns.AthirdsolutionistoplaceaniconsomewhereontheperipheryofthescreenthatindicatesthattheuseriswatchingtheUIandthenallowthisiconalwaystotrackwiththeusersview(OculusVR,2015a).Aconsiderableamountofpreviousresearchhasfocusedoneyegazeasanaugmentedinputincombinationwithanotherinputdeviceortechnique(seeforexampleFono&Vertegaal,2005,Miniotas,Špakov,Tugoy&MacKenzie,2006,Yamato,Monden,Matsumoto,Inoue&Torii,2000,Salvucci&Anderson,2000andZhai,Morimoto&Ihde,1999).Thisresearchisnotpresentedinthisthesissincethisthesisfocusoneyegazedirectionestimatedbyheadorientationusedastheonlyinputandinteractiontechnique.Likewise,researchdescribingeyegazeestimationwhereitclearlyrequireseye-trackingtechnology,andtheresearchisnotbelievedtobeapplicablefortheheadgazeinteractionmethod,hasalsobeenexcluded.Thenextsectionwilldefineuserexperienceandexplainimportantfactorsinfluencingit.Furthermore,itwillalsodescribehowtheuserexperiencecanbemeasured.

2.5 User experience

Userexperience(UX)isassociatedwithseveraldifferentmeanings(Forlizzi&Battarbee,2004).NielsenandNorman(n.d.)summarizetheirdefinitionofUXbystatingthat‘”Userexperience”encompassesallaspectsoftheenduser’sinteractionwiththecompany,itsservices,anditsproducts.’TheInternationalOrganizationforStandardization(ISO)defineUX,withtheirstandard9241-210,asusersperceptionandresponsethathasresultedfromtheuseortheanticipateduseofaproduct,asystem,oraservice(ISO,2010).Moreover,UXincludestheusersbelieve,emotions,perception,preferences,physical,andpsychologicalresponseandalsobehavioursandperformancethathappensbefore,during,andaftertheuse.Additionally,therearethreeimportantfactorsinfluencingtheUX.Theyarethesystem,theuser,andthecontextofuse(ISO,2010).Awell-knowndefinition,highlightingthosethreeimportantfactorsistheonedescribedbyHassenzahlandTractinsky(2006):

UXisaconsequenceofauser’sinternalstate(predispositions,expectations,needs,motivation,mood,etc.),thecharacteristicsofthedesignedsystem(e.g.complexity,purpose,usability,functionality,etc.)andthecontext(ortheenvironment)withinwhichtheinteractionoccurs(e.g.organisational/socialsetting,meaningfulnessoftheactivity,voluntarinessofuse,etc.).

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Hassenzahl(2008)alsodescribestwodifferentdimensionsofUX.Pragmaticqualityiswhatherefertoas‘…theproduct’sperceivedabilitytosupporttheachievementof“do-goals”,suchas“makingatelephonecall”…’whilehedonicqualityrefersto‘…theproduct’sperceivedabilitytosupporttheachievementof“be-goals”,suchas“beingcompetent”…’ThepragmaticqualityisrelatedtotheproductsutilityandusabilityinrelationtoapotentialtaskwhilethehedonicqualityfocusontheSelf,likethequestionofwhysomeoneownanduseaparticularproduct.HassenzahlclaimsthatthepragmaticqualitymightleadtothefulfilmentofhedonicqualitywhilethehedonicqualitycontributesdirectlytotheUX.Whilepragmaticattributesemphasizetheindividuals’behaviouralgoal,thehedonicattributesemphasizetheindividuals’psychologicalwellbeing(Hassenzahl,2008).AkeycomponenttoassuringqualitativeUXistheusability(Hartson&Pyla,2012).AccordingtotheISOstandard9231-11,usabilityisdefinedas‘theextenttowhichaproductcanbeusedbyspecifieduserstoachievespecifiedgoalswitheffectiveness,efficiency,andsatisfactioninaspecifiedcontextofuse.’(ISO,1998).However,efficiencyandeffectivenessarenotenoughtomakeuserssatisfied,sincetheyarealsolookingforemotionalsatisfaction(Shih&Liu,2007),whichisanotherimportantpartoftheUX(Hartson&Pyla,2012).TheemotionalimpactisthecomponentoftheUXthatinfluencesusersfeelings.Thisincludeseffectssuchaspleasure,fun,thejoyofuse,aesthetics,desirability,pleasure,novelty,originality,sensation,coolness,engagement,novelty,andappeal.Thiscanalsoincludedeeperemotionalfactorssuchasself-expressionandself-identity,theprideofownershipandafeelingofcontributiontotheworld.TheimportanceofthisisexpressedbyHassenzahl,BeuandBurmester(2001)whoclaimthat‘Themostbasicreasonforconsideringthejoyofuseisthehumanisticviewthatenjoymentisfundamentaltolife.’OneconceptusedtoimprovetheUXofsystems,andatechniquethatsupportsusersduringinteractionsareaffordances(Hartson,2003).Therearefourdifferenttypesofaffordancesincludingcognitive,physical,sensory,andfunctionalaffordances.Thefirsttypeiscognitiveaffordancesthathelpuserswiththeircognitiveactions,suchasthinking,learning,andremembering.Thiswhilephysicalaffordanceshelpusersperformsphysicalactions,suchasclicking,touching,pointing,andmovingobjects.Moreover,sensoryaffordancesaimathelpinguserswithsensoryactions,suchasseeing,hearing,andfeelingthings.Thefourthandfinaltypearefunctionalaffordancesthathelpusersgetthingsdoneanduseasystemtodowork(Hartson,2003).ThisthesiswilluseHassenzahlandTractinsky’s(2006)definitionthatUXisaconsequenceofauser’sinternalstate,thecharacteristicsofthedesignedsystem,andthecontextwithinwhichtheinteractionoccurs.Furthermore,itisextendedalsotoincludethepragmaticandhedonicquality(Hassenzahl,2008)whereusabilityisanimportantcomponent(Hartson&Pyla,2012).Finally,thedefinitionalsoemphasisestheemotionalimpact.MoreimportantlyisthatUXcannotbedesigned;itcanonlybeexperienced.QualitativeUXisthereforeconsideredtobeUXfulfillingtheusers’subjectivehedonicandpragmaticgoalswithrespecttothecontextofusewithhighusabilityandadesirableemotionalimpact.Inthefollowingsection,theapplicationofvideoondemandservicesisbrieflydescribed.Thesectiondefinestheserviceandimportantfactorsofit.

2.6 Video on demand service

Videoondemand(VoD)allowspeopletoaccessvideos,forexamplemovies,fromvideoserversonabroadbandnetwork(Li,Liao,Qiu&Wong,1996).Userscancontroltheirexperiencesandchoosewhichvideocontenttoconsumeandatwhattimeandlocationtheyprefertoconsumeit(Mustilloet

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al.,1997).Moreover,theserviceisoftenpersonalizedandinvolvesone-to-oneinteractionbetweentheuserandtheservice(Choi,Reaz&Mukherjee,2012).TodevelopVoDservicesthatleadtoqualitativeUX,itishighlyimportanttounderstandtheusersbehaviourwhileinteractingwiththeservice.Fromtheuserperspective,Netflixmediastreamingserviceisnotaboutaccessingmanydifferentmovies,itisabouthavingaquieteveningwithaspouse,makingtimepassatanairportorindulginginaTVshow(Goodmanetal.,2012).ThedesignofVoDservicesusuallydependsontherequestpatternsoftheusers(Choietal.,2012).Anexampleisthatvideospopularitycorrelateswiththerequestrate.Awell-knownfactisthatvideopopularityfollowstheZipfdistribution,whichisanequationthatshowsrequestfrequencyofcertainmovietitles.Moreover,videospopularitymaydecreasewithtimesincetheinterestdecreasesafterpeoplehavewatchedit.Thepopularitycanalsochangeduetotheintroductionofnewvideosornewrecommendations(Yuetal.,2006).AnotherimportantfactorinVoDservicesisthedailyaccesspatternoftheusers’behaviour(Choietal.,2012).Afteravideoisstartedandtheuserstartstowatchit,theusermightneedtointeractwiththeservicetochangethestateofthevideo.Possibleuserinteractionscanbeclassifiedasplay,resume,stop,abort,pause,jumpforward,jumpbackward,fastsearchandslowmotion(Lietal.,1996).Outoftheseinteractions,pauseisthemostcommonlyused(Costa,Cunha,Borges,Ramos,Rocha,Almeida&Ribeiro-Neto,2004).Forlongvideos,jumpforwardandjumpbackwardareequallycommonactions.However,thevideoplaytimeisusuallyquiteshort(Yuetal.,2006).Morethanhalfofallstartedvideosareplayedlessthan10minutesand70%areterminatedwithinthefirst20minutes.SincemanyVoDservices,likeNetflix,offerthousandsofoptionsofcontent,acentralproblemofVoDservicesisthattheexperiencehasbecomemoreaboutselectingapieceofcontentthansimplywatchingit(Vanhemert,2014).Usersareforcedtochoosecontentbeforethewatchingexperiencecanbegin.Vanhemertclaimsthat‘Netflixisgreatwhenyouwanttowatchsomething,butit’sterriblewhenyouwanttowatchanything.’ThenextsectionwillbrieflydescribeexistingguidelinesrelatedtothedesignofVRGUIs.Itsummarizesearlierresearchandguidelinesthatpractitionerscurrentlyuse.

2.7 Research related design principles for virtual reality graphical user interfaces

Thissectionpresentsexistingguidelinesofrelevancefortheresearchaim.Theguidelinesincludehowtodesignfor3Dinteraction,VR,VRGUI,headgaze,andvideoinVR.Table1showsanoverviewofthe10designguidelinesdiscoveredandpresentedinthissection.Thefirstdiscoveredguidelineistoallowuserstobelazy(Wilson,2011).Bowman(2013)claimsthat‘UsersinHMDsdon’twanttoturntheirheads,muchlessmovetheirbodies.’Iftheusersareforcedtostretchtheirnecksandturnintheirseat,itcouldleavethemsore,whichdegradestheUX(Sundström,2015).Arecommendationis,therefore,tonotrequireuserstomovetheirheadorbodymorethannecessary.Bowman(2013)similarlyemphasisesnottoneglectusercomfort.LargemovementscouldalsobeaproblemsinceitwouldincreasethelikelihoodoftheuserclashingwiththesurroundingenvironmentoutsideoftheHMD(Sundström,2015).

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Theseconddiscoveredguideline,relatingtothefirst,istoallow‘magic’interaction(Bowmanetal.,2004).Interactionin3Disoftenthoughtofas‘natural’,butformanynoviceusersoperatinga3DUIisanythingbutnatural(Bowman,2013).Bowmanetal.(2004)recommendviolatingassumptionsabouttherealworldinthevirtualworld.Iftheinteractionisdesignedtobe‘magical’insteadof‘natural‘,itallowsuserstogobeyondtheperceptual,cognitive,andphysicallimitationsoftherealworld(Bowmanetal.,2004).Insteadoftheuserhavingtowalkuptoanobjectandreachoutwiththehandtograbit,s/hecanuseavirtuallaserpointertograbitfromadistance.Thethirddiscoveredguidelineisthatthenumberofdegreesoffreedom(DOF)theuserisrequiredtocontrol,ingeneral,shouldbeasfewaspossible(Mineetal.,1997).Whendesigningfor3Dinteractions,itisimportanttounderstandthedesignspaceandtheinteractiontechniquesthatcanbeused(Bowman,2013).Thedesignspaceof3Dinteractionvariesdependingonthenumberofdevicesandmappingsavailable.Bowmanetal.(2008)statethat2Dtasksarecognitivelyeasierthan3Dtasks.Furthermore,real-worldtasks,atleastmostofthem,arenotfully3D(Bowmanetal.,2008).Asaresult,mosthumansareusedtodealingwith2Dortwoandahalf-dimensional(2,5D)anddonothavetheskillstodealwith3Dproblems.Bowmanetal.(2008)therefore,suggestcreating2Dalternativesforasmanytasksaspossiblein3DUIstoincreasetheusability.Furthermore,itisrecommendedtouse2Dinputdevicesover3Dinputdevices(Bowmanetal.,2008).Acomparisonofinputspecificationsbetweenmouse-orpen-basedsystemsand3Dtechnologiesrevealsthat2Dtechnologiesaremuchmoreprecise(Teather&Stuerzlinger,2008).WhenaninputwithhighDOFisusedforataskthatrequiresalowernumberofDOFs,theresultcanbethatthetaskisunnecessarilydifficulttoperform(Bowman,2013).Anexampleiswhenuserswanttoselectamenuitem,whichisinherentlyaone-dimensionaltask,andtheyneedtopositiontheirvirtualhandswithinamenuitemtoselectit.TheUIthenrequirestoomucheffortfromtheusertoperformthetask.Moreover,forcinguserstopositiontheirhandsinthree-dimensionstopressavirtualbuttonslowsdowntheinteractionandincreasesuserfrustration(Mineetal.,1997).ThisrelatestoBowman’s(2013)recommendationtokeeptheUIsimple.Heclaimsthatiftheuser’sgoalissimple,thereshouldbeasimpleandeffortlesstechniquetoreachit.

Table1.Anoverviewofthe10guidelinesdiscoveredofrelevancefortheresearchinthisthesis.

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Theguidelinecanbefollowedinseveraldifferentways.KeepingthenumberofDOFstoaminimumcanbeaccomplishedbyusingalower-DOFinputdevice,ignoringsomeoftheinputDOFs,orbyusingphysicalorvirtualconstraints(Bowman,2013).ThefourthguidelinediscoveredisthatVRneedsaffordancestoindicatewhichobjectstheusercaninteractwithandwhentheinteractiontakesplace(Sundström,2015).Onewaytohelpusersperformthecorrectactionistousereal-worldmetaphors(Bowmanetal.,2004;Sundström,2015).Moreover,Alger(2015b)suggeststhatdesignersshouldusethehumaninstinctstotheiradvantagewhentheyaredesigningVRGUIs.Thefifthguidelinediscoveredistodesignforthehardware(Bowman,2013).Bowmanclaimsthatwhatmightworkforonedisplayorwithonedevicerarelyworkexactlythesamewayonadifferentsystem.WhenusingthesameUIonadifferentdisplayordevice,theUI,andtheinteractiontechniquesoftenneedtobemodified.Thisiscalledthemigrationissue(Bowman,2013).Anotherimportantpartofwhythedesignshouldbeforthetechnologyistohavetheergonomicandphysicalconstraintsofthetechnologyinmind(Chen,2014).Ifthisisnotconsidered,interactionsaremorelikelytobedisrupted.Thesixthguidelineforeasy-to-useinteractiontechniquesistonotusefloating,interpenetratingorinvisibleobjects(Bowmanetal.,2008).Bowmanclaimsthatfloatingobjectsshouldbetheexceptionandnottherule.Hereferstotherealworld,whichtheuserisfamiliarto,wherefloatingobjectsbarelyexistandmostobjectsareattachedtootherobjects.Interpenetratingobjectsshouldbeavoidedsincemanynoviceusershaveproblemsrecoveringfromsuchsituations.Furthermore,arecommendationisnevertoforceuserstointeractwithinvisibleobjects(Bowmanetal.,2008).TheseventhguidelineistodisplaytheVRGUIatareasonableandcomfortabledistancefromtheuser(OculusVR,2015a;Chen,2014).Lubosetal.(2014)suggestthat3Dselectiontasksthatrequirehighprecisionshouldbeplacedclosetotheuserseyes.OculusVR(2015a)claimthattheidealdistanceisusuallybetweenonetothreemetersawayfromtheuser.Thissinceplacinganobjecttooclosetotheusercancauseajarringexperience.AspreviouslydescribedinSection2.3,therecommendationistokeepobjectsatadistanceofatleast75centimetresfromtheuser(OculusVR,2015b)butnotfurtherthan20metresaway(Chu,2014).Guidelineeightistouseagazecursororcrosshairwhenthegazeisusedastheinputmodality(OculusVR,2015a).Usinggazeselectionwithoutacursororcrosshairhasbeenreportedasmoredifficulttousesincetheuserhastoestimatewheretheheadgazeiscurrentlylocated.TheninthguidelineistodesignthevideoscreeninVRtocoverlessthan70degreesofthehorizontalFOV(OculusVR,2015a).OculusVRclaimsthisisthesizethatisrequiredtoallowuserstoviewthefullscreenwithoutturningtheirheads.Thetenthandfinalguidelineistoavoidrapidmovementsandnottodropframesorlooseheadtracking(Sundström,2015;Wilson,2011).Ifframesaredroppedortheheadtrackingislostitwillappearasanerrorintheusers’consciousness(Wilson,2011).Thiscouldcausetheusertofeelsick.Also,rapidmovementscouldhavethesameeffect(Sundström,2015).Theycanalsocausetheusertofeeldisorientedinthevirtualenvironment.Thefollowingsectionwilldescribetheresearchaimandobjective.Itwillalsocovertheexpectedresultandlimitationsoftheresearch.

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2.8 Research aim and objective

Perry(2016)claimsthatthe‘Thedoortomass-marketvirtualrealityisabouttoburstopen.’ConsideringmostHMDshasbarelybeenlaunched,thepublishedresearchaddressinggeneralusabilityandhowtheseHMDsaffectusersislimited(Serge&Moss,2015).Furthermore,threedecadesofresearchhaslaidthefoundationforthetechnologyofHMDs,buttherehasbeenalackoffocusontheUIs(Dorabjeeetal.,2015).Moreover,OculusVR(2015b)claimsthatnotraditionalinputmethodisidealforVRandthatinnovationandresearchareneeded.Oneofthemostresearchedfieldsofhuman-computerinteractionhasbeentheuseofeyegazeasaninputmodality(Bazrafkanetal.,2015).However,theusabilityofeyegazeasinputstillremainsmarginal.Moreover,thereisashortageofresearchconcerningtheuseofheadorientationinputtoestimategazedirection.Theaimofthisthesisistocontributetotheunderstandingofwhataspectsareimportanttoconsiderwhendesigningvirtualrealitygraphicaluserinterfaces-controlledbyheadorientationinput-forqualitativeuserexperiences.Inordertoachievethisaim,thefollowingresearchquestionhasbeendeveloped:

Whataspectsshouldbeconsideredwhendesigningagraphicaluserinterfaceinvirtualreality-controlledbyheadorientationinput-foraqualitativeuserexperience?

Theuserinterface(UI)isthepartofacomputerthatpeoplecansee,listento,talktoorinanyotherwayunderstandanddirect(Galitz,2007).Virtualreality(VR)isdefinedtobeaninteractive,three-dimensionalcomputer-synthesizedenvironment(Prattetal.,1995;Barfield&Furness,1995)seenfromthefirst-personpointofviewandcontrolledinrealtimebytheuser(Bowmanetal.,2004).Moreover,itincludesavirtualworld,sensoryfeedback,interactivity,andimmersion(Sherman&Craig,2003).Headorientationinputreferstothewaythattheorientationoftheuser’sheadscanapproximatetheuser’sgazedirectionandbeusedasaninputmodalitytocontrolaUI.Onewaytosimulatethistotheuserisbyhavingacursorfloatinginthemiddleoftheirfieldofview(Mine,1995).Theinteractionmethodthatusesheadorientationinputtoapproximatetheuser’sgazedirectionisinthisthesisreferredtoasheadgaze.Userexperience(UX)canbedefinedasaconsequenceofauser’sinternalstate,thecharacteristicsofthedesignedsystem,andthecontextwithinwhichtheinteractionoccurs(Hassenzahl&Tractinsky,2006).Furthermore,itisalsoextendedtoincludethepragmaticandhedonicquality(Hassenzahl,2008)whereusabilityisanimportantcomponent(Hartson&Pyla,2012).Finally,thedefinitionalsoemphasisestheemotionalimpact.However,UXcannotbedesigned;itcanonlybeexperienced.QualitativeUXisthereforeconsideredtobeUXfulfillingtheusers’subjectivehedonicandpragmaticgoalswithrespecttothecontextofusewithhighusabilityandadesirableemotionalimpact.Inordertoachievethethesisaim,thefollowingobjectivehasbeencreated:

Investigateandanalysetheconceptsinvolvedintheresearchquestionandhowtheyareaffectingtheuserexperience.

Theachievementoftheaimofthisresearchenablesthepossibilitytodevelopguidelinesforthedesignofgraphicaluserinterfacesforvirtualreality–controlledbyheadorientationinput–foraqualitativeuserexperience.

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2.8.1 Expected contributions

Severalcontributionsareexpectedfromtheresearch.ThemainexpectedcontributionisguidelinesthatshouldbetakenintoconsiderationwhendesigningVRGUIs–controlledbyheadorientationinput–forqualitativeUX.Furthermore,theresearchisexpectedtocontributetotheunderstandingofVRGUIsshouldbedesignedfortheapplicationofVoDservices–controlledbyheadorientationinput–forqualitativeUX.Exceptforthisspecificapplication,theresearchisalsoexpectedtocontributetotheunderstandingofthecoreconceptsindividually.ThiscouldincludetheunderstandingofhowVRGUIsshouldbedesignedforotherapplicationsthanVoDservicesorhowtodesignUIscontrolledwithheadorientationinputinothercontexts.Additionally,AccedowillalsobenefitbasedonthefactthattheirexistingVRGUIprototypewillbetestedandevaluatedduringtheresearch.Finally,theresearchisexpectedtocontributetoafoundationforfutureresearchwithinthefield.

2.8.2 Limitations

TheresearchaimistocontributetotheunderstandingofwhataspectsareimportanttoconsiderwhendesigningVRGUIsforqualitativeUX.Thisislimitedtodesignasvisualappearanceandinteraction,andnottodesignasaprocessofdevelopingVRGUIs.TheVRGUIsinfocusarealsolimitedtotheonesexperiencedwiththeuseofHMDs.Alsotheinputofheadorientationislimitedtotheinteractionmethodofheadgazeastheonlyinteractionmethodusedtocontrolthesystemwithnoadditionalinputdeviceorinteractionmethod.Theapplicationoftheresearchalsoservesasanaturallimitation,sincetheUXwillonlyberesearchedforVoDservices.Moreover,theusersandtargetgroupfortheresearcharebasedonAccedo’spreviouslyusedexpectationsthattheusersarebetween20to45yearsold.TheyhavealsochosenonlytofocusonusersthatarenotwearingglassessincealltheHMDsdonotyetsupportuserswithglasses.ThistargetgroupwasfurtherlimitedtopeoplethatwereexperiencedusersofVoDservicesbutwithnoorlimitedexperienceofVR.Furthermore,thetargetgroupwaslimitedtopeoplethatusetechnologyonadailybasiswithoutbeingnoviceusersortechnologyexperts.Finally,thetargetgroupwaslimitedtopeoplethatcouldcomfortablyspeakandreadSwedishandEnglishsincetheusabilitytestsandinterviewswereperformedinSwedishbutAccedo’sVRprototypethatwastestedisdevelopedinEnglish.TheresearchisalsolimitedtotheapplicationofVoDservicescontainingonly2Dvideocontent.WithregardtotheresearchbeinglocatedinSweden,itwillmainlyshowaresultofuserspartoftheSwedishcultureandnotcoverculturaldifferences.Furthermore,theauthor’sknowledgeofhowtomeasuredegreesofFORandFOVinVRislimitedandcanonlyberoughlyestimated.ThefinallimitationisthatthebackgroundresearchdoesnotcoverallexistingguidelinesforVRGUIsorheadorientationinput.

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3 Method Whilethepreviouschapterpresentedthebackgroundanddefinedthedifferentconceptsinvolvedintheresearchquestionandaimofthethesis,thischapterdefinesanddescribesthemethodsusedfortheresearch.Thefirstsectionfocusesontheresearchdesignwhilethefollowingsectioncontinuestofurtherdescribeeachofthemethodsused.Section3.2definestheheuristicevaluation,andthethirdsectionfocusesoninterviewswhileSection3.4explainsusabilitytests.Thefinalsectiondefinesthemethodofusingsurveysforresearchpurposes.

3.1 Research design

Inordertoanswertheresearchquestion,thegoaloftheresearchwastocollectdataaboutwhatinfluencetheuserexperience(UX)whenheadorientationinputandheadgazeisusedtocontrolagraphicaluserinterface(GUI)invirtualreality(VR).Furthermore,theapplicationvideoondemand(VoD)serviceswasalsoconsideredanimportantconceptintheresearch.However,thereisashortageofVoDservicesinVRcontrolledbyheadorientationinputandtherefore,theresearchcouldnotexclusivelyfocusontestingdifferentapplications.Sincetheresearchquestioninvolvedseveralconceptsforthisspecificapplication,therewereseveraldifferentcombinationsoftheseconceptstogetheroralonethatcouldberesearchedtogaininsights.Qualitativeresearchfocusesongainingcontextandinsightregardinguserbehaviour(Unger&Chandler,2012).Equallyimportantisthatitprovidesresultsthatareclosertothecoreoftheusers’subjectiveexperiencescomparedtoquantitativeresearchapproaches(Andersonetal.,2010).Therefore,qualitativeresearchwasselectedasthemainresearchapproachforthethesis.Additionally,alimitedamountofquantitativedatawasalsocollectedandanalysedtogetherwiththequalitativedata.Userresearchcanbeusedtobetterunderstandtheusersandtesttheirbehaviourinaspecificdomain(Unger&Chandler,2012).Itisaprocesswiththeaimtoinvestigatehowpeopleperceiveanduseservicesandproducts(Goodman,Kuniavsky&Moed,2012;Anderson,McRee&Wilson,2010).Thekeyconceptsofuserresearcharetounderstandtheusersneedsonbothanintellectualandintuitivelevelandseethingsfromtheirperspective(Andersonetal.,2010).OneimportantpartinuserresearchandUXdesignistheconceptofgoalssinceproductsareonlyseenastoolstoaccomplishhigher-levelgoalsforusers.Thefirststepinperforminguserresearchistodefinetheprimaryusergroups(Unger&Chandler,2012).Amethodtodevelopthefirstdefinitionoftheusergroupsistocreateaprovisionaldefinitionbasedonknowledgeavailableintheprojectteam.Thenextstepistoplanfortheusersparticipationintheresearchbytheuseofdifferentmethods.Atthebeginningofaproject,thiscouldbeinterviews,surveys,focusgroupsorcontextualinquiry’s(Unger&Chandler,2012).Thereareseveralreasonstousemorethanonlyonemethodfortheresearch.Usingtwoormoreresearchmethodsprovidesaricherpictureoftheuserthanonemethodcanprovideonitsown(Unger&Chandler,2012).Moreover,triangulationistheprocessofusingseveralmethodstofindproblemsinasystem(Wilson,2014).Themethodisusedtocompareseparatesourcesoffindingstodiscoverconsistenciesanddiscrepancies(Barnum,2011).Additionally,itisthemostpowerfulmethodtodeterminewhichproblemsaretherealproblemsinaproduct(Wilson,2006).Theproblemsthatarerepeatedlyfoundaremorelikelytobetherealproblems.Anotherreasontousethemethodistoeliminatetheriskthatthefoundproblemsarefoundbasedonthespecificmethod

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used(Banister,Dunn,Burman,Daniels,Duckett,Goodley,Lawthom,Parker,Runswick-Cole,Sixsmith,Smailes,Tindall&Whelan,2011).Finally,triangulationleadstoamorecontextuallevelofthecollectedinformation(Biggerstaff,2012)andenrichestheanalysisoffindings(Barnum,2011).Timeandfinancialresourcesareusuallywhatdecidestheamountofmethodsusedinthesameresearch(Barnum,2011).ForUXevaluation,Hartson&Pyla(2012)recommendstoimprovise,adapt,andtocustomizemethodsandtechniquestofittheevaluationgoalsandneeds.Thiscouldimplicateexcludingsteps,introducingnewsteps,andchangingthedetailsofastep.Themethodsthatwereselectedforthisresearchareheuristicevaluations,interviews,usabilitytestsandasurvey.TheywereselectedwiththeaimtocollectUXdataaboutthedifferentinvolvedconcepts.Table2showhowthedifferentmethodsgatherinsightsaboutdifferentconcepts.Alternativemethodsthatcouldhavebeenusedwereforexamplefocusgroups(Unger&Chandler,2012)orperspective-basedUIinspection,cognitivewalkthrough,oraformalusabilityinspection(Wilson,2014).Timeconstraintsandtheauthorsexistingknowledgeoftheothermethodsmadethesemethodsprioritizedlowerwhentheselectionwasmade.Inthefollowingsectionsofthechapter,eachmethodwillbedefinedandexplainedfurtherincludingthemotivationbehindwhytheywereselectedfortheresearch.

3.2 Heuristic evaluation

Heuristicevaluationsareatypeofuserinterfaceorusabilityinspectionwhereanindividualorateamevaluatesaprototypeoraproductbasedonalistofheuristics(Nielsen,1993;Nielsen&Molich,1990).Themaingoalofusingthemethodistofindasmanyusabilityanddesignproblemsaspossiblewithlimitedeconomicandtimeresources(Wilson,2014).Oneadvantageofheuristicevaluationsisthatitisaneasyandintuitivemethodtolearn(Hartson&Pyla,2012).Theevaluationsarerelativelytimeeffectivetoperform,requiresnospecialresourcesorrealusers,andcanprovideadditionalbreadthandcomplementotherassessmenttechniques(Wilson,2014).Therefore,themethodisefficienttouseinthebeginningofaUXprocess(Hartson&Pyla,2012).Whenthemethodisusedbeforeusabilitytesting,itcancontributetoidentifyinggoalsforthetesting(Barnum,2011).Additionally,theuseoftheevaluationbeforetheusabilitytesthastheadvantagethatthefacilitatoroftheusabilitytestwillbefamiliarwiththeUIandhaveabasicunderstandingoftheproblemsthattheusersmightexperienceduringthetest.Onthecontrary,thereisadebatewhethertheheuristicevaluationisagoodmethodtofindthe‘real’problems(Wilson,2014).Oneexampleisthataproblemforabeginnermightbeperceivedasapositivefeatureforanexpertandviceversa.Thequalityoftheheuristicevaluationsresultsalsovariesbasedontheexperienceoftheevaluators.Hartson&Pyla(2012)describethattherewillalwaysbecertainUXproblemsthatappearinrealliveuser-basedinteractionsthatwillnotappearinanyheuristicevaluationorotherinspectionmethod.Anotherriskisthatheuristicevaluation,likeotherinspectionmethods,createsfalsenegatives,whicharesituationswheretheinspectors

Table2.Howthedifferentresearchmethodscoverdifferentpartsoftheconceptsintheresearch.

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identifiedproblemsthatturnedouttonotbearealproblemornotasimportantastheevaluatorthought(Hartson&Pyla,2012).However,thesepossiblerisksareperceivedasminimisedwiththeuseofcomplementingresearchmethodsandthetriangulationoftheresultsbetweenthem.Severalstepsareincludedintheplanningofaheuristicevaluation(Wilson,2014).Thefirststepistorecruittheevaluatingteam.Widthanddepthofthefunctionsthatareexpectedtobecoveredbytheevaluationtogetherwiththeevaluators’experience,domainknowledge,andthecomplexityoftheUIdeterminethesizeoftheteam(Wilson,2014).Mostheuristicevaluationsareperformedbyateamoftypicallytwoorthreeinspectorsbutoneisalwaysbetterthannoneandsometimesasingleevaluatorisenoughforearlyprojectstages(Hartson&Pyla,2012).Thenextstepoftheplanningistodecidethelistofheuristicsthatshouldbeusedfortheevaluation(Wilson,2014).NielsenandMolich(1995)developedasetofheuristicsthatareoftenmentioned(Barnum,2011;Hartson&Pyla,2012)andcommonlyused(Unger&Chandler,2012).Nielsen(1995)laterdecidedtorefinetheheuristics(seeTable3).OtherheuristicsareforexampleGerhardt-Powals(1996)tenresearch-basedheuristicsandWeinschenkandBarkers(2000)20generalheuristics.UngerandChandler(2012)recommendkeepingthelistofheuristicstoamanageablesizesinceatoolargeamountofthemcouldmaketheevaluationunnecessaryhardtoperform.NextHartson&Pyla(2012)recommendsevaluatorstocreateinspectionquestionsbasedonthechosenheuristics.Thefollowingpartoftheplanningistocreateamethodforhowtheproblemsshouldbecollected,organized,andpresented(Wilson,2014).Onewayistouseachart,eitherprintedordigital,withdifferentfieldswheretheinspectorscandocumenttheproblem,therelatedheuristic,theseverityoftheproblem,andwheretheproblemwasfound.Evaluatorsthathavenotperformedaheuristicevaluationpreviouslyshouldthen

Table3.Nielsen’s10usabilityheuristics(Nielsen,1995).

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practicethemethod(Wilson,2014).Materialsandinformation,suchasuserprofilesandenvironmentswheretheproductwillbeusedneedtobeprepared.Furthermore,accesstotheproductneedstobeprepared.Thefinalstepofthepreparationsistodecidewhichapproachtheevaluatorsshouldfollow.Oneapproachisthattheevaluatorsfollowalistoftaskscenariosandanotheralternativeistofollowalistofgoalstobereachedduringtheevaluation(Wilson,2014).Theevaluationsshouldbeperformedindividually(Wilson,2014).First,theevaluatorsneedtoreadthebackgroundinformationincludinggoals,personas,andenvironmentdescriptions.Next,theyneedtoinspectthetaskscenarios.Duringtheevaluation,eachproblemshouldbelistedindividually.Thissimplifiestheprocessofidentifyingiftheproblemsarelocalorglobal.Afteralltheindividualevaluationsareperformed,asummarizinglistofallthefoundproblemsshouldbecreated.Thelistshouldbesortedinawaythatissuitablefortheproject.Itcouldbesortedbasedontheseverityoftheproblemsorgroupedafterthedifferentpartsofthesystem(Wilson,2014).

3.3 Interview

Userinterviewsareindividualconversationswithusersfromtheprimarytargetgroup(Unger&Chandler,2012).Goodmanetal.(2012)describethatinterviewsareneededtoreallyunderstandusers’experiences.Itisamethodappropriatetogatherdataabouttheusershonestopinions,preferences,andattitudes(Unger&Chandler,2012).Whenusinginterviews,itissometimesdifficulttocollectstraightforwardopinionsandcollectinformationaboutattitudesandcontext(Unger&Chandler,2012).Theparticipantswillnotalwayssaywhattheybelieveandsometimestheywillanswertoadifferentquestionthantheonebeingasked(Goodmanetal.,2012).Thiscanusuallybesolvedbyobservingtheuserduringtheinterviewandlookforcuesinbehavioursuchashesitationorbodylanguage.Anothersolutionistoshowinterestintheparticipants’opinionsandbeingpersistentaskingthesamequestionagainwithslightchangesinwordingandemphasis(Goodmanetal.,2012).Recruitingistheprocessoffinding,inviting,andschedulingtherightpeopletouseintheresearch(Goodmanetal.,2012).Theprocessconsistsofthreebasicsteps:determiningthetargetaudience,findingmembersofthataudience,andconvincingthemtoparticipateintheresearch.Theprocessofdeterminingthetargetaudiencestartswithwritingabouttheproduct’stargetaudienceandthenbydecidingifthereisaspecificpartofthetargetgroupthatwillresultinbetterfeedbackforthespecificresearch(Goodmanetal.,2012).Itisalsoimportanttoconsidertheamountofpreviousexperiencetheyhavewiththeproduct,withcompetingproducts,andiftherearecharacteristicsthatshouldbeavoided.Whentherecruitingstarts,arecommendationistotrytoavoidrecruitingparticipantswiththeexactsamequalitiesiftherearevariationsallowedwithinthetargetgroup(Goodmanetal.,2012).Anexampleisifthetargetgroupspansoveragesfrom20to30yearsoldpeople,thentheparticipantsshouldbeofdifferentagesinbetweenandnotall25yearsold.Toolsforrecruitingincludeforexampleonlineforums,mailinglists,socialnetworkingservices,askingacquaintances,orusingads(Goodmanetal.,2012).Friendsandfamilyshouldbeavoidedsincetheirrelationshiptotheinterviewerwillaffecttheirbehaviour.Whendecidinganumberofparticipantstorecruit,itisalsoimportanttoplanforrecruitedparticipantsthatcancelordonotshowup(Goodmanetal.,2012).Thepreparationsbeforetheinterviewsincludecreatingalistofquestionsthatwillresearchtheusers’previousexperienceofthesystem,theirgoals,andneeds(Unger&Chandler,2012).Itisalso

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importanttodecidehowstructuredtheinterviewsshouldbe.Asemi-structuredapproachcanbeusediftheamountofdataismoreimportantthanconsistency.Thesemi-structuredapproachstartswiththeintervieweraskingpreparedquestionsbutallowstheconversationtofollowanaturalpatterntocontinueresearchinginterestingcommentariesfromtheparticipants(Unger&Chandler,2012).Goodmanetal.(2012)recommendplanningtheinterviewguidetobefollowedtostartwithsimplerquestionsandthencontinuewithmoreseriousquestions.Furthermore,thequestionsshouldbeopenandflexiblesotheparticipantscanintroducetopicsandquestionsthattheinterviewerwouldnothavebeenabletopredict(Hartson&Pyla,2012).Ifaparticipantisaskedtochoosefromseveraloptions,s/hewillchooseoneevenifnoneoftheoptionssuittheparticipant’sopinion(Goodmanetal.,2012).Moreover,thequestionsshouldnotcoverseveralsubjectsorbebinary.Whentheinterviewiscompletelyplanned,itshouldbetestedtocontrolifanyofthequestionsarehardtounderstandorifthetimescheduleneedstobeadjusted(Unger&Chandler,2012).Beforetheinterviewstarts,theparticipantsneedtobeinformedoftheirroleintheprojectandthetermsfortheirparticipation(Vetenskapsrådet,1990).Alloftheparticipantsshouldbeofferedasmuchconfidentiallyaspossibleandbeaskedtoleaveconsentfortheirparticipation.Duringtheinterview,itisimportanttomaketheparticipantfeelcomfortabletalkingtotheinterviewersinceitwillhelpthepersontoanswerquestionsinanhonestway(Goodmanetal.,2012).Atechniquetomaketheparticipantfeelcomfortableistoshowinterestfortopicsnon-relatedtotheinterviewsinceitwillhelpthepersonfeelmorerelaxed.Furthermore,theinterviewerneedstoworkwithanopenmindtonotexcludetopicsthatseemtootrivial.Inordertorelievetheinterviewer’scognitiveabilitiesduringtheinterviews,asoundrecordercanbeused.Thentheinterviewercankeephisorherfocusontheparticipantandthequestionsinsteadoffocusingontakingnotes(Goodmanetal.,2012).

3.4 Usability test

Usabilitytestsarebasedonuserstryingtoperformtypicaltasksinasystemwhileamoderatorobservesandinsomecaseaskquestionstounderstandtheusers’behaviour(Unger&Chandler,2012).Thetestsaresuitedtoevaluateexistingsystemsorprototypesthatneedtobeimproved.Formativetestingiswhenaproductisindevelopment,andthegoalistofindandrectifyproblems(Barnum,2011).Thesearetypicallybasedonsmallstudiesrepeatedduringdevelopment.Theresultingdataoftentaketheformofproblemdescriptionsanddesignrecommendations(Sauro&Lewis,2012).Usabilitytestsarecommonlyusedinthedesignphaseofaprojectwhenadesigniscreated,testedandthenimprovedandtestedagain(Unger&Chandler,2012).Barnum(2011)recommendscombiningusabilitytestswithheuristicevaluationssinceeachofthemethodsbringsvaluetotheprocessofcreatingproductsthatareuseful,usable,anddesirable.Thecombinedresultofthetwomethodswillalsoprovideastrongerconfirmationoftheproblemsthatarethe‘real’problems(Barnum,2011).Thefirststepofplanningausabilitytestistoestablishtestgoals,decidetheproductthatshouldbetested,includingwhere,andhowthetestshouldbeperformed(Barnum,2011;Unger&Chandler,2012).Barnum(2011)describethatthetestgoalsshouldexplainthepartoftheusers’experiencethatisoffocustoresearchinthetest.Whentheproductandthetestgoalsareestablished,thenextstepistoplanwherethetestsshouldbelocated.Usabilitytestscanbedoneinlabs,conferencerooms,orinthefield.Furthermore,thelocationalsoincludespreparingtherightequipmentforthe

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test(Hartson&Pyla,2012).IfquantitativeUXdataisplannedtobecollecteditisusefultohavetimersorsoftwareprepared(Vermeerenetal.,2002).However,itisalsopossibletocollecthigh-precisiontimingdatafromvideorecordingsofthesession.Usabilitytestscanbeperformedforbenchmarkingtoestablishmetricsoftheproductorasacomparisonofdesigns(Barnum,2011).Thetypicaltest,oftenperformedinformativeusabilitytesting,istogivetheusersanumberoftaskswithinscenariosandgatherfeedbackontheirexperienceoftheproduct.Usabilitytestscanbeusedasaquantitativeorqualitativemethod(Unger&Chandler,2012).Theadvantagesofusingthetestasaquantitativemethodisthatitgeneratesresultsthatcanbecontrolledstatisticallyatlateriterationsanditlowersthelikelihoodthatanindividualmoderatorhasaffectedtheresult.Theadvantagesofusingtheusabilitytestasaqualitativemethodisthatisusuallylessexpensivesincefewerusersareneededforthetest.Itisalsoamoreavailablemethodformoderatorswithlimitedexperienceofperformingthetestandleadstodatawithahigherinformationdensity(Unger&Chandler,2012).AccordingtoNielsenandLandauer(1993),thenumberofusabilityproblemsthatwillbefoundinausabilitytestinrelationtotheamountsofusersparticipatingcanbecalculatedusingamathematicalmodel.WhileNielsenandLandauer’sstudyshowsthatatleast15usersneedtobeinthetesttodiscoveralltheusabilityproblems,Nielsen(2000)claimthatthebestresultcomesfromtestingnomorethanfiveuserspertestandrunningasmanysmalltestsascanbeafforded.Ausabilitytestwithfiveuserswillleadtoabout85%oftheusabilityproblemsbeingfound(Nielsen,2000).RecommendationsforrecruitingoftheparticipantsfollowthesamerecommendationsaspreviouslydescribedforinterviewsinSection3.3.Essentialelementsthatneedtobeincorporatedforgoodresultsinsmallusabilitystudiesincludedefiningauserprofile,creatingtask-basedscenarios,usingathink-aloudprocess,andmakingchangesandtestingagain(Barnum,2010).TheuserprofileisthebasisforrecruitingparticipantsforthestudyandispreviouslycoveredinSection3.3.Task-basedscenariosaretasksembeddedwithinscenarios.Theyusuallyincluderealisticdescriptionsbasedonusers’goals.Usingathink-aloudprocessmeansencouragingparticipantstosharetheirthoughtsverballywiththemoderatorduringthetest.Anadvantageofthemethodisthatitwillbecomeeasierforthemoderatortounderstandwhytheusersdowhattheydowithoutthemoderatorhavingtoguesswhattheyarethinking(Barnum,2011).Beforethetests,aparticipantincentiveshouldbedeterminedandprepared(Barnum,2011).Theincentiveshouldbeexperiencedasagiftandnotasabribe.Thisinordertonotinfluencetheremarkstheparticipantsmake.Appropriateincentivesincludecash,giftcards,ordebitcards.Duringtheusabilitytest,thefirststepistomeetandgreettheparticipant(Barnum,2011).Thefollowingpartistogivetheuserapre-testbriefing.Inordertoalwayssharethesameinformationwithalltheparticipants,themoderatorshoulduseascriptforthispartofthetest(Barnum,2011).Aftertheparticipantisverballyinformed,s/heshouldbeaskedtosignaconsentformcontainingthesameinformation(Hartson&Pyla,2012).Vetenskapsrådet(1990)stronglyrecommendsfollowingfourspecificrequirementsintheresearch.Thefirstrequirementistoinformtheparticipantofthepurposeandaimoftheresearch.Secondly,theparticipantshouldalwaysleaveconsentfortheparticipationandthattheyareawarethattheparticipationisvoluntary.Thethirdrequirementisthattheparticipantsshouldbeofferedasmuchconfidentiallyaspossibleandthattheirprivateinformationshouldbeprotectedfromothers.Finally,theparticipantsshouldbeinformedofhowthegathereddatawillbeused(Vetenskapsrådet,1990).Thefinalstepbeforetheteststartsistoinformtheparticipantsaboutthethink-out-loudprocess(Barnum,2011).Atypicaltestusuallylastsbetween30minutestofourhoursforanindividual

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participant(Hartson&Pyla,2012).However,HartsonandPylarecommendskeepingthesessionundertwohours,sinceitwillbecomemoredifficultfortheparticipanttostayfocusedifthetestislonger.Duringthetest,differenttypesofdatacanbegathered.SauroandLewis(2012)recommendnottoletthesamplesizestopatestfromusingstatisticstoquantifythedataandinformdesigndecision.Completionrates,forexample,arethemostfundamentalofusabilitymetrics(Nielsen,2001).Alsotasktimes,theamountoferrors,andsatisfactionratescanbeusedasmeasurements(Sauro&Lewis,2012).Moreover,problemscanalsobequantifiedintermsoffrequencyandseverity.

3.5 Survey

Surveysareseriesofquestionsusedtofindpatternsinbehaviourandpreferenceamonglargernumbersofpeople(Unger&Chandler,2012).Theyareusefulwhentheaimistoresearchpreferencesratherthanperformance.Surveysalsoserveasgoodsupplementstootherformsofresearch.SauroandLewis(2012)claimthatsurveysareoneoftheeasiestmethodstocollectattitudinaldata.Furthermore,manyparticipantsdonotalwaysliketostatenegativeopinionsoutloudbutareoftenwillingtoexpressthemwhenfacedwitharankingsystem(Unger&Chandler,2012).AnotheradvantageisthatsurveysarevaluabletosupplementobjectiveUXevaluationsdatawithsubjectivedatadirectlyfromtheusers(Hartson&Pyla,2012).Additionally,themethodiseasytouseforbothanalystandparticipantanddoesnotrequireaspecificlocation.Surveyscanyieldbothquantitativedataaswellasqualitativeuseropinions(Hartson&Pyla,2012).Typicallytheycontainacombinationofopen-endedcomments,binaryresponsesandLikert-typeratingscales(Sauro&Lewis,2012).Whenplanningasurvey,itisimportanttoconsidertheuserstargetedandwhichmethodfordistributingthesurveywillgivethebestresult(Unger&Chandler,2012).Forexample,ifthetargetuserstendtobeactiveInternetusers,sendingthemanonlinesurveycouldbethebestsolution.Anotherimportantfactorwhencreatingasurveyistotakeintoconsiderationtheamountoftimetheparticipantsarewillingtospendansweringit(Unger&Chandler,2012).Ifcompensationisofferedtotheparticipants,thesurveycangenerallybelonger,butifnocompensationisoffered,thesurveyneedtobekeptshorttohelpensurepeoplewillcompleteit.UngerandChandlerrecommendkeepingthecompletiontimerequiredbetweenfivetotenminutes.Anotherpartoftheplanningistodecidehowlongthesurveywillrun.Alternativesincludelettingthesurveyrununtilacertainamountofresponsesiscollectedoruntilacertaindeadline,dependingonwhichhasthehighestpriority(Unger&Chandler,2012).AspreviouslydescribedforinterviewsandusabilitytestsinSection3.3andSection3.4Itisalsoimportanttoinformtherespondentsofthepurposeandaimoftheresearch(Vetenskapsrådet,1990).Finally,itisimportanttoconsiderwhichtoolwillbeusedtocollectandanalysethedata(Unger&Chandler,2012).Ifthesurveyisrunningonline,thetoolmayhaveoptionsforviewingandanalysingtheresult.Otherwise,amethodforhowtoenterthedataintoanotheranalysingtoolisneeded.

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4 Procedure Thischapteraimstodescribehowthedifferentmethodswereexecutedduringtheresearch.Thefirstsectionwilldescribetheprototypethatwasusedintheheuristicevaluationandtheusabilitytests.Section4.2explainstheprocedureoftheheuristicevaluation.Thefollowingsectiondescribeshowtheinterviewsandtheusabilitytestswereperformed.Finally,Section4.4describeshowthesurveywasexecuted.

4.1 Accedo’s virtual reality video on demand prototype

Aspreviouslystated,thereisashortageofavailablevideoondemand(VoD)servicesinvirtualreality(VR)controlledwithheadorientationinputandheadgaze.However,thecompanyAccedohadahighfidelityprototypeofexactlythatkindofapplication.TheprototypeisdevelopedwiththeprojectnameHimalaya,andithasbeenpresentedpubliclybutnotofficiallyusabilitytested.Withrespecttotheaimoftheresearch,theprototypehasbeenusedasaproducttobeusabilitytestedinordertogatherUXdataandinsights.Theprototypeisavailableintheformofanapplicationunderdevelopment.ItcanbedownloadedtoanysmartphoneusingAndroidoriOSwithAccedo’spermission.Theprototypecanthenbeexploredusinganyhead-mounteddisplay(HMD),orso-calledVRset,thatisusedwithasmartphone.ResolutionofthesmartphonescreenandthequalityoftheHMDaretwofactorsinfluencingthequalityoftheexperience.Whenenteringtheapplication,abigvideoscreenisdisplayedinthecentreoftheusers’fieldofview(FOV)anddependingonhowtheusers’changetheorientationoftheirheads,differentfunctionsandmenuswillappear(seeFigure7).Thedifferentinformationareaswillappearasanimationswhentheusers’changetheorientationoftheirheads.Sundström(2015)previously(seeSection2.2)describeddifferentdisplaymethodsinVRandthisprototype’scontentisdisplayedfloatingintheairbutislockedtotheworld.Furthermore,itisdisplayedasacurvedtilemenu,directedtowardstheuser.Acrosshairisconstantlydisplayedinthecentreoftheuser’sFOVandwhentheuserturnshisorherhead,thecrosshairfollowsandremainsataconstantpositioninthecentreofhisorherFOV.ThecrosshairisusedasacursorandwhentheusersplacethecrosshairoveraUIelementthattheusercaninteractwithitwilldisplayhoveringinformationaboutitandstartacircularprogressbarcountingdownthetimeuntiltheselection,

Figure7.Howthedifferentmenu’sappearwhentheuserturnshisorherheadinAccedo’sprototype.

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equalasamouseclick,willoccur.ThepredeterminedtimebeforetheclickstartsaftertheheadgazeisplacedoveraUIelementis200millisecondsandthetimeittakesbeforetheselectionisperformedis2000milliseconds.DifferentfeedbackfollowsfromdifferentUIelementselections.Ifauserplacestheheadgazecursorstraightforwardatthescreens/hewillseethevideoscreenandiftheheadgazeisretainedatthesamelocationforapredeterminedperiodoftime,thescreenwillzoominandbecomelargertotheuser.Thiswhilethesurroundingswillturncompletelyblacksotheonlythingtheuserseesisthevideoscreen.Iftheuserchangestheorientationofhisorherheadslightlydown,amenuwillopenupoverthelowerpartofthescreen(seethecentreimageinFigure8).Themenucontainsfunctionstoplay,pause,fast-forward,rewind,andrewind10seconds.Thismenuwillbereferredtoastheplaymenu.Iftheuserlocatestheheadgazeoverthearrowspointingtotheleft,thevideowillstartrewinding.First,itwillfollowaspeedoftwotimesthenormalrunningtimebutlateritwillacceleratestepbystepuntilitreachesaspeedof16timestheoriginalspeediftheuserretainstheheadgazeoverthearrows.Thefast-forwardingarrowspointingtotherightusethesamefunctionalitybutreversed.Therestoftheicons,excepttheorangebuttoninthecentrewilltriggerthecircularprogressbartostart

Figure8.AnoverviewoveralltheinformationareasandmenusthatopenwhentheuserchangeshisorherheadorientationinAccedo’svirtualrealityprototypeofavideoondemandservice.

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andiftheuserretainstheheadgazeovertheiconuntiltheprogressbarisfull,theselectionwillbecompleted.Theorangeiconinthecentreisnotpossibletointeractwithandisjustavisualdetail.Iftheuserturnshisorherheadtotheleftofthescreen,amenuofroundbuttonswillappear(seetheleftimageinFigure8).Thismenuisreferredtoasthemainmenuanditcontainsbuttonsforthefunctionsofdifferentcontentcategories.Thedifferentbuttonscanbechosentodisplaymovies,TVshows,channels,ortoexittheVRexperience.Afteraselectioniscompleted,theusershouldturnhisorherheaddownbelowthescreentocontinuelookingforaspecificvideointhedisplaymenu.Thedisplaymenuencompassesvideopostersandtitlesofdifferentvideosina3Dcarouselmenu(seetheimageatthebottominFigure8).Themenuchangescontentbasedonwhichselectionischoseninthemainmenu.Inthemenu,theusercanscrolltotherightandleftsidetoaccessmorecontent.Thescrollingwillbeginwhentheuserplacestheheadgazecursorontheleftorrightsideofthedisplayedmenucontent.Moreover,thescrollingwillcontinueuntiltheusermovestheheadgazecursortothecentreofthedisplayedcontent.Aprogressbarbelowthemenushowshowmuchcontentisavailableandwhereamongthecontent,theuseriscurrentlyplaced.Aselectionofonevideoisperformediftheuserplacestheheadgazecursoroveritandstaysoverituntilthefullselectiontimeiscompleted.Thenthevideowillstarttoplayabovethedisplaymenuonthevideoscreen.Iftheuserturnshisorherheadup,thesettingsmenuwillappear(seethetopimageinFigure8).Itcontainsroundbuttonswithdifferentonandofffunctionality.Theusercanchoosetoturnonaleaklightfunctiondisplayingabackgroundlightbehindthescreenorturnonandoffsoundeffectsforbuttonsandinteractions.S/hecanalsochangetheshapeofthescreentobeflatorcurvedandturnonandoffsceneryofHimalayaMountainsthatappearbehindthescreenandthemenusontheblackbackground.Iftheuserturnshisorherheadtotherightsidepastthescreenedge,informationaboutthevideocurrentlyplayingwillappear(seetheimageontherightsideinFigure8).Theinformationisonlyfordisplayandtheusercannotinteractwithitmorethanreadit.IfamovieorTVshowiscurrentlyrunningonthescreentheareacontainsthevideotitle,yearofrelease,ashortsummaryofthevideosstory,thedirectorofthevideo,actorsinthevideo,andalsothevideoposter.Ifachanneliscurrentlyrunningonthescreen,theinformationareawillshowthenameofthechannelandadescribingtextaboutit.Thevideocontentintheprototypeis2Dandonlyafewtrailersofseveralcombinedvideosarecurrentlyavailableasplaceholdersintheapplication.Whenauserselectsandstartsaspecificvideo,thevideocontentdisplayedwillalwaysbeoneofthetrailers.

4.2 Heuristic evaluation procedure

Thefirstmethodusedintheresearchwastheheuristicevaluation.Basedontimeconstraintsandwiththeapproachofusingthemethodquickandinformalitwasperformedbytheauthoralone.Norecruitingofevaluatorswasthereforerequired.Nielsen’s10usabilityheuristics(1995)(previouslypresentedinTable2inSection3.2)wereselectedfortheevaluationbasedontheauthor’spreviousknowledgeandtherecommendationsfromUngerandChandler(2012)ofkeepingthelistofheuristicstoamanageablesizetonotovercomplicatetheprocedureofperformingit.BasedonHartsonandPyla’s(2012)recommendations,inspectionquestionswerecreatedfortheevaluation.Thefirstquestionswas‘Isitcleartotheuser,whatishappeninginthesystem?’.One

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questionsperheuristicwascreatedandusedduringtheevaluation(seeAppendixAforthecompletelistofquestions).TheremainingpartoftheplanningandperformingoftheevaluationfollowedWilson’s(2014)recommendations(seeSection3.2).Theproblemsweredocumentedinadigitalchartwithfieldsfortheproblemdescription,theproblem-relatedheuristic,theseverityoftheproblem,andwhereinthesystemtheproblemwasfound.Sincetheauthorwasalreadyexperiencedwiththemethod,therewasnoneedtopractisethemethodbeforeperformingtheevaluation.Alistoftasks,basedonassumedimportantactionstheuserwouldwanttoperform,wascreatedfortheevaluation.Thelistincludedstartingavideo,pausingavideo,fast-forwardingandrewindinginavideo,changingtoanothervideo,andfindingaspecificvideo.Finally,theaccesstotheproductwaspreparedandpreviousdocumentationwasinspected.Documentationincludeddocumentsfromthedevelopmentoftheprototypewiththoughtsconcerningthedevelopment,thetargetgroupandinformationaboutcompetitors’solutions.Theevaluationwasperformedbytheauthoransweringtheinspectionquestionswhiletryingtoperformthelistoftaskspreviouslycreated.Alltheproblemswerelistedseparately.Whentheevaluationwascompleted,thelistwassortedbasedontheseverityofthefoundproblemsandproblemsthatappearedtobeglobalbutwaslistedtwoormoretimesaslocalweremergedintooneglobalprobleminstead.

4.3 Interview and usability test procedure

Theinterviewsandtheusabilitytestswerecombinedandperformedaftereachotherduringthesamesessionwiththesameparticipants.Thiswasdonewithrespecttothetimeconstraintsandlimitedresourcesoftheresearchbutalsowiththeaimtoreachahigherqualityofthegathereddata.Userswerefirstinterviewedandthenparticipatedintheusabilitytest.TheinterviewservedasanaturalintroductionfortheparticipantstostartthinkingabouttheirVoDpreferencesandbehaviour,andwhattheywereexpectingfromavideoinVR.Furthermore,thedatafromtheinterviewsandtheusabilitytestscouldbecomparedforeachparticipant,withtheaimtoreachabetterunderstandingoftheusersandtheuserexperience(UX)oftheprototype.FollowingtherecommendationsofGoodmanetal.(2012)(seeSection3.3),thefirststepwasdeterminingthetargetaudience.ThetargetaudiencefortheHimalayademoprototypedevelopedbyAccedowasfoundinoneofAccedo’sdocumentsdescribingtheaudienceas20to45yearoldpeoplewithoutglassessincemanyHMDsdonotworkwithglassesyet.Furthermore,thegroupwasdescribedascomfortablespeakingEnglish,sinceEnglishisthelanguageusedintheprototype.Theywerealsodescribedascomfortablewatchingonlinevideos,suchastheonesinVoDservices,andnotjustlinearTV.Thepartofthetargetgroupthatwasselectedastheonethatwouldgivethebestfeedbackconsideredpreviousexperiencetheusersmighthavewithaproductorcompetingproductsandiftherewerecharacteristicsthatshouldbeavoided.Basedonthis,thegroupwaslimitedtopeoplewithnoearlierorverylimitedexperienceofVRtocapturethefirstimpression,experience,andbehaviour.ThegroupwasalsolimitedtouserswhounderstoodandcouldspeakbothEnglishandSwedishsincetheinterviewwasperformedinSwedishinSweden.Furthermore,thegroupwaslimitedtoexperiencedVoDserviceusers.Theyweredefinedaspeopleusingcomputersandsmartphonesondailybaseswithoutbeingbeginnerswithtechnologyortechnologyexperts.Thelimitationsdefinedtheuserprofilefortherecruitingprocesstobegin,alsofollowingBarnum’s(2011)recommendationsforusabilitytests.

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FollowingNielsen’s(2000)recommendations,theamountofuserstobeusedintheresearchwasdecidedtobefive.Anadditionaluserwasaddedinordertoplanforpossiblefallouts,followingrecommendationsfromGoodmanetal.(2012).TherecruitingalsofollowedrecommendationsfromGoodmanetal.(2012)(seeSection3.3).Facebookwasusedtorecruitacquaintancesandtheauthor’sfriendsandfamilysharedthepost,whichmadeitreachfurtherthanonlytheauthor’ssocialnetwork.Whenselectingparticipantsamonginterestedpeople,variationamongthemwasstrivedfor.Threemenandthreewomenoftheagesbetween27and45yearsoldwererecruited.FollowingBarnum’s(2011)recommendations,theparticipantswereofferedgiftcertificatesforthecinemaasanincentive.Eachparticipantwasbookedforaseparatesessionscheduledtolast90minutes.ThetimeofthesessionwasbasedonrecommendationsfromHartsonandPyla(2012)tokeepeachsessionundertwohours.TheinterviewquestionswerecreatedbasedonUngerandChandler’s(2012)recommendations(seeSection3.3).Withtheaimtoresearchtheusers’previousexperience,goals,andneedsasemi-structuredapproachwasselected.FollowingsuggestionsfromGoodmanetal.(2012),theinterviewguidestartedwithsimplerquestionsandthencontinuedwithmoreseriousquestions.Furthermore,thequestionswerecreatedtobeopenandflexible,basedonHartsonandPyla’s(2012)recommendations.Thefirstpartoftheinterviewinvolvedquestionsabouttheusers’previousexperienceandknowledgeofVoDservices.Itwasfollowedwithquestionsresearchingtheirbehaviour,goals,opinionsandvaluesregardingVoDservices.Onequestionwasforexample‘WheredoyouusuallyuseVoDservices?’.ThesecondpartoftheinterviewcoveredtheuserspreviousexperienceofVRandtheiropinionsandexpectationsofvideoinVR.Onequestionwasforexample‘HowdoyoufeelaboutwatchingvideocontentinVR?’.Finally,theparticipantswereaskedabouttheirpreviousexperienceandknowledgeofusingtheirheadoreyestointeractwithsystems(seethecompletelistofquestionsaskedduringtheinterviewinAppendixB).TheusabilitytestwasplannedtofollowrecommendationsfromBarnum(2011)andUngerandChandler(2012).Thefirststepaccordingtothemistoestablishtestgoalsforthetest.Thegoalswerebasedontheresultoftheheuristicevaluation.GoalsfortheusabilitytestweretotestiftheVRGUIwaseasytolearnandiftheusersabilitytoperformtasksimprovedastheybecamefamiliarwiththesystem.Furthermore,thetestwasaimedtoresearchifuserscouldfindtheinformationtheyneededinordertocompleteataskwithoutassistance.AnothergoalwastoseeiftheuserscouldeffectivelyandsuccessfullyreachdifferentgoalsthatwereassumedtobetypicalforVoDusers.Moreover,anotheraspectwastoresearchiftheusersexperiencederrorsandhowwelltheywereabletorecoverfromthem.Finally,atestgoalwastoresearchtheparticipantsexperienceduringthetestandthedifferenttasksincluded.Thenextstepwastodecidealocationforthetesting.ConferenceroomsattheAccedoofficeinStockholmwerebookedforthepurpose.FollowingHartsonandPyla’s(2012)recommendations,theequipmentfortheroomswaspreparedaswell.Adecisionwasmadetomostlygatherqualitativedatabutalsoasmallamountquantitativedata,suchascompletionratesandcompletiontimes.TheprototypewasinstalledonaniPhone6plus,sinceitwasthesmartphonewiththelargestscreenavailableandsincetheauthorispreviouslymostfamiliarworkingwithiOSdevices.AniPhone6plusscreenhasa1920-by-1080-pixelresolutionat401PPI(Apple,2016).TheHMDselectionwasalsobasedonavailability.HomidoisanHMDthatallows

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userstoenterVRwiththeirsmartphones(Homido,2014).Ithassettingstosettheeyetolensdistance,custom-madeVRlensesthatoffera100-degreefieldofview(FOV),interchangeablecontactsurface,interchangeabledistancesettingandiscompatiblewithmostrecentsmartphones(Homido,2014).Toallowthemoderatortofocusonmoderatingthetestandaskingquestions,followingrecommendationsfromGoodmanetal.(2012),soundandvideorecordingwasusedduringthesessions.Fortheinterviewquestionswhentheprototypewasnotbeingtested,aniPhone5swasusedforsoundrecordingandwhentheprototypewastested,asystemcamerawithrecordingfunctionalityandatripodwasused.Inordertoseeandhearwhattheparticipantswereseeingandhearingduringtheusabilitytest,theiPhonewasconnectedtoaTVscreenintheroomwithanHDMIcableandanHDMItolightningadapter.UsuallytheHMDisusedwithearphonesconnectedtothesmartphonewiththeapplicationforthemostimmersiveexperiencebutsincethiswouldhavepreventedthemoderatorfromhearingwhattheparticipantwashearingandalsolimitthepossibilityofgivinginstructionsandaskingquestionstotheparticipantduringthetest,thesoundwasledtotheTVinstead.Thismighthaveaffectedtheexperiencebutwasasolutiontoaproblemthatmightnothavehadanyothereasysolution.ThefullsetofequipmentandhoweverythingwassetupduringthetestcanbeseeninFigure9.

Figure9.Thesetupofequipmentandhowitwasusedduringtheusabilitytest.

Table4.Listoftask-basedscenariosusedintheusabilitytest.

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Barnum(2011)claimsthattask-basedscenariosarerequiredtohavegoodresultsfromausabilitytest.Therefore,task-basedscenariosweredeveloped,focusingonthetestgoalsandtheusers’goals.Atotalofninetask-basedscenarioswereprepared(seeTable4).FollowingrecommendationsfromVetenskapsrådet(1990)(seeSection3.3)aconsentformwaspreparedfortheusabilitytest.Themoderatorscriptforthetestwasalsopreparedwithreminderstoexplainthethink-aloudmethodfortheparticipantsbeforetheteststarted.Finally,followingrecommendationsfromBarnum(2011)andUngerandChandler(2012),thewholeinterviewandusabilitytestweretestedduringapilottest.Thepilottestwasperformedwiththeaimtoconfigurequestionsandcontrolthetimerequiredforthewholesession.Nochangesweremadeafterthepilottestsincenoproblemswerediscovered.FollowingtherecommendationspreviouslydescribedinSection3.4,theparticipantwasfirstgreetedandpre-testbriefedbythemoderatorfollowingapreparedscript.Allparticipantswereaskedtosignaconsentformaftertheywereinformedofthepurposeofthestudy,howthedatawouldbeused,thattheirparticipationwascompletelyvoluntaryandthattheywereofferedacertainlevelofconfidentiality.Theinterviewwassoundrecordedandwhenitwasfinished,theparticipantwasinformedabouttheusabilitytest.TheyweretoldtheywouldcontroltheUIwiththeirheadsandapproximatedgazebutwerenotgivendetailsabouthowthiswouldwork.Themoderatorstartedthevideorecordingafterconfirmingwiththeparticipantsonelasttimeandthenstartedtheapplicationonthesmartphone,placeditintheHMDandaskedtheparticipantstoplaceitontheirheads.Participantswereinformedaboutsimulatorsicknessandremindedofthepurposeofthetest.Theywerealsoinformedofthelimitationsoftheprototype,suchasthelackofrealvideocontent.Furthermore,theywereinformedabouttheprocedureofthescenariosandthewaythemoderatorwouldfollowtheiractionslookingattheTVscreenconnectedtotheiPhoneintheirHMDs.Finally,theywereinformedaboutthethink-out-loudmethod.Themoderatorstartedthevideorecordingandthenstartedtheapplication,placeditintheHMDandaskedtheparticipantstoputitontheirheads.BeforetheyenteredtheVRworld,theywereinformedofthefirsttask-basedscenarioinordertobeabletostartstraightawayandinordertocapturefirstimpressions.Thefirsttask-basedscenariowastoexploretheapplicationandsharereactionsandthoughts.Theywereaskedtodescribewhattheythoughttheycoulddointheapplication.Thesecondscenariowastofigureoutthetitleofthevideothatwascurrentlyrunning.Thethirdscenarioofthetestwasfortheparticipanttofindandstartanothervideo.Afterthat,theparticipantswereaskedtofastforwardinthevideo.Thefifthandsixthscenariowastoplayandpausethevideo.ScenariosevendescribedthattheywantedtowatchepisodeoneofseasononeoftheTVshowTheSimpsons.Theywereaskedtofindandstarttheepisode.ThefollowingscenarioaskedthemtofindtheTVshowMadMen.Inthelastscenario,theparticipantswereencouragedtoexplorefurtherandfindasmuchfunctionalityaspossible.Afterthetest,participantswereaskedquestionabouttheirexperienceandtheiranswersweresoundrecorded(thefulllistofquestionscanbeseeninAppendixC).Onequestionwasforexample‘Wastheresomethingthatsurprisedyou?’andanotherwas‘Diditfeellikeyoucouldcontroleverythingyouwantedtocontrolintheuserinterface?’.Intotal,mostinterviewandtestsessionswerecompletedwithin70minutesbutoneofthesessionsalmostusedthefullscheduledtimeof90minutes.Thesessionendedwiththeusersreceivingtheincentivefortheparticipation.

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4.4 Survey procedure

Thesurveywascarriedoutwiththeaimtoresearchtheusers’preferencesandattitudesregardingVoDservices.Sincetheaimofthestudywaswide,thetargetgroupwasextended.Thetargetgroupforthesurveywasdecidedtobepeoplebetweentheagesof20to45yearsoldwithexperienceofusingVoDservices.TheirexperienceofVRwasnotrelevantforthepurposeofthesurveyandwasthereforenotincludedasapartofthetargetgroupdefinition.ThepreparationofthesurveyfollowedUngerandChandler’s(2012)recommendations(seeSection3.5).Sincetheaimwastocollectasmanyresponsesaspossible,andthetimetogatherdatawaslimitedandnoincentivewasavailable,thesurveywaslimitedtofivequestions,withafewsubquestions.Anapproximationandtwopilottestsofthesurveyshowedthetimetocompletethesurveytobeaboutfiveminutes.Thepilottestsweresuccessfulandnoproblemsoccurredsonoadjustmentwasmade.Intheintroductorypartofthesurvey,therespondentswereinformedthatonlyrespondentswithinthetargetgroupwereaskedtoanswerit.Therespondentsweretheninformedaboutthesurvey’spurpose,howthecollectedinformationwouldbeusedandtheconditionsfortheircontribution,followingVetenskapsrådets(1990)recommendationsforresearch.Finally,importantterminologyinthesurveywasdefined.Thequestionswereofdifferenttypes,somewithratingscalesforhowfrequentlytheuserstartedaVoDservicewithacertaingoalandanotherquestionwaswithrankingchoicesofwhatfunctionalitythatwasthemostimportant.Twoquestionsweredesignedwithacommentboxforopenanswersandonewasdesignedwithmultiplechoices.Thefirstquestionwasastatementof‘Thisrarely/oftendoIstartavideoondemandserviceto…’andthenfollowedbyfivedifferentstatementsthattherespondentswereaskedtoanswer.Thefivedifferentstatementswere:

1.� FindsomethingtowatchwhenIdonotknowinadvancewhatIwouldliketowatch.2.� FindsomethingtowatchwhenIalmostknowinadvancewhatIwouldliketowatch.3.� FindaspecificvideowhenIknowinadvancewhatIwouldliketosee.4.� ContinuetowatchavideoIwaswatchingpreviously.5.� Controlifthereisacertainnewvideoavailableintheservice.

Foreachofthestatements,therespondentshadsixdifferentanswerstochoosefrom.Thesewere‘never’,‘rarely’,‘quiterarely’,‘sometimes’,‘quiteoften’and‘often’.Thesecondquestionwas‘Rankthefollowingalternativesafterwhatismostimportantinavideoondemandservice.’.Alternativesincluded:

1.� ToeasyandquicklybeabletofindthevideosIknowinadvancethatIwouldliketowatch.2.� TogetinspiredandeasyandquicklyfindvideostowatchwhenIdonotknowinadvance

whatIwouldliketowatch.3.� ToeasyandquicklybeabletocontinuewatchingthevideowhereIthelasttimestopped

watchingit.Thealternativeshadtoberankedwithanumberbetweenoneandthree,andtheycouldnotshareanumber.Numberonewasthoughttobethemostimportantwhilenumberthreewouldshowwhichwastheleastimportantalternative.Thethirdquestionwasthestatement‘WhenIknowexactlywhatIwouldliketowatch,thenIoftenfindthevideoby…’.Itwasfollowedbyacommentboxopenforanyanswertherespondentmightgive.

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Thefourthquestionwasthestatement‘WhenIalmost(butnotexactly)knowwhatIwouldliketowatch,Ioftenknow…’.Thisquestionwasfollowedbythefollowingninemultiplechoicestatements:

1.� Whichgenre(s)thevideoshouldbelongto2.� Whichvideo(s)thevideoshouldbesimilarto3.� Whichactor(s)thevideoshouldhaveinit4.� Whichfeelingthevideoshouldgive5.� Whichdirector(s)thevideoshouldbecreatedby6.� Whichratingthevideoshouldatleasthave7.� Howthemoviepostershouldlook/looks8.� Whichyearthevideoshouldbefrom9.� Other(followedbyacommentboxforownalternatives)

Thefinalquestionwas‘This(ifanything)frustratesmewhenIuseavideoondemandservice(otherthaninternetconnectionproblemsandthevideocontentofferingintheservice).’.Acommentboxwasusedtocollecttherespondents’answers.Thetoolselectedforthesurveywasbasedoneconomicalfactors,theavailablequestiontypes,andthebuilt-inanalysisfunctionality.SurveyMonkeywasusedsinceitwasafreetoolwithquestiontypesalternativesthatotherfreetoolswithanalysisfunctionalitydidnotoffer.FollowingUngerandChandler’s(2012)recommendations,thedistributionchannelwasselectedbasedonthetargetgroup’stypicalbehaviour.Therefore,thesurveywasdistributedonFacebook,bothasapostintheauthor’spublictimelineandalsoasapostinagroupwithstudents.Furthermore,thepostwassharedbyfriendsandfamilyandtherefore,reachedmorethanjusttheauthor’ssocialnetwork.Thepostcontainedalinktothesurvey(seethedesignofthesurveyinAppendixD).Thesurveywasactivatedforfourdays,startingonthe31May2016andwhenitwasclosed,60respondentshadanswered.Theanswerswerethencollectedandanalysed.Nextchapterwilldescribetheresultandanalysisofthedifferentresearchmethodsusedinthisthesis.Furthermore,itwillpresentthefoundationofthedevelopedguidelinespresentedinChapter6.

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5 Result and analysis Goodmanetal.(2012)claimthereisnospecificcorrecttechniqueforanalysisofqualitativedata.Thetechniqueselectionshouldbebasedonwhichquestionneedtobeanswered,currentlimitationsandalsofromtheinquisitor’sknowledgeandpreferences.However,thefirstrecommendedstepoftheanalysisistopreparetherawdataformanipulation.Itservesasanaturalpartoftheanalysissinceanaturalfiltrationwilloccurduringtheprocess(Goodmanetal.,2012).Thedatafromtheheuristicevaluationandthesurveywaspreparedbybeingsummarizedintodocumentstocreateabetteroverview.Moreover,theresultsfromtheheuristicevaluationwereanalysedandseverallocalproblemsdiscoveredwasmergedintooneglobalproblem.ThesurveydatawascollectedfromSurveyMonkey’sfreeonlinetoolandtransferredtodocumentstoprovideabetteroverviewforeachquestionsresponse.Thefirststepofanalysisoftheinterviewsandtheusabilitytestsweretotranscribetherecordings.Animportantpartoftranscribingthedataistocapturewhattheparticipantsreallymeantorwasthinkingaboutsomethingeveniftheysaidsomethingelse(Goodmanetal.,2012).Therefore,eachaudiorecordingwaslistenedtoseveraltimestotranscribenotonlywhatwassaidanddonebutalsohesitation,expressedemotions,orothercuesofwhatthepersonreallymeantwhens/hewereansweringthequestion.Thesameprocedurewasfollowedforeveryvideorecordingfromtheusabilityteststocapturemovements,faceexpressions,bodylanguage,andothercuesthatrevealedtheparticipantsexperience.Quantitativeandqualitativemeasurementssuchastimetocompletetasks,completionrates,howtheparticipantsperformedtasks,errors,recovery,usersatisfaction,andemotionswerealsodocumentedduringthetranscription.Alltheinterviewsandtheusabilitytestsweretranscribedindividuallyintodigitaldocuments.Goodmanetal.(2012)claimthereareseveraladvantagesanddisadvantageswithdocumentingdigitallyaswellasmanuallyandrecommendstomixtheuseofbothtechniquesforthebestresult.Therefore,allthedigitallydocumenteddatawasprinted.Whenanalysed,notesandhighlightwereaddedmanually.Thedatafromtheusabilitytestsandtheinterviewswasevenmoresummarizedandsortedintotablestosimplifythecomparingandanalysis.Thesewerealsoprintedandanalysedagain(seeFigure10).Thischapterpresentstheresultsfromeachofthemethodsused.Section5.1presenttheusabilityproblemsfoundintheheuristicevaluation.ThefollowingsectionpresenttheresultsfromtheinterviewswhileSection5.3presenttheresultsfromtheusabilitytests.Section5.4presentstheresultsfromthesurvey.Thefinalsectionofthechapterpresentsacomprehensiveanalysisofalltheresearch. Figure10.Alldatawassummarized,sorted,printed,andanalysed.

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5.1 Heuristic evaluation result and analysis

Theheuristicevaluationresultedinalistof14usabilityproblems.Threeseveritygrades,fromlowtohighareusedtoclassifytheproblemsdiscovered.Sixoftheproblemsareestimatedtobeofhighseverity(seeTable5)andfourofthemrelatetothefifthheuristicoferrorprevention.Threeofthehighseverityproblemsareglobalsincetheyoccurinseverallocationsinthesystem.

Thefirstglobalproblemofhighseverityisthataselectionofafunctionoccursbeforetheuserhasfinishedreadingandinterpretingthefunctionnameandicon.Sincethedescribingtextofthefunctionisnotvisiblebeforetheusershoverwiththeheadgazecursorovertheicon,theuserhasonly2000milliseconds,ofreadingandinterpretingthefunctionnamebeforetheselectioniscompleted.TheproblemrelatestoseveralofNielsen’s(1995)usabilityheuristics,includingthevisibilityofsystemstatus,usercontrolandfreedom,errorprevention,andrecognitionratherthanrecall(seeTable3inSection3.2foranexplanationoftheheuristics).

Anotheroftheglobalusabilityproblemofhighseverityisthatitishardtoseetheselectionresult,whichsometimesincludeseeingwheretheuserneedtocontinuetheinteractiontoreachhisorhergoal.Oneexampleofthisiswhentheuserturnsonoroffafunctionalityinthesettingsmenu(seeFigure8inSection4.1)butdonotseetheresultoftheactionsinceitisoutsideoftheuser’sconeoffocusthatisexperiencedasverylimitedtowherethebuttonforthefunctionalityisplacedsincetheheadgazeneedstobeplacedoveritfor2000millisecondsinordertocompletetheselection.Thesameproblemoccurswhentheuserisselectingabuttoninthemainmenubutisunabletoseetheresultoftheselectionthatoccursinthedisplaymenuatthesametime.Sincetheuserisnotawareofwhatchanges/hetriggeredwiththeselection,s/healsodoesnotknowwhattodonextorhowtogoback.Therefore,theproblemrelatestoNielsen’s(1995)usabilityheuristicsnamedvisibilityofsystemstatus,matchbetweensystemandtherealworld,andrecognitionratherthanrecall.

Thethirdglobalusabilityproblemofhighseverityisthatthereisnovisiblewayfortheusertoundoorgobackafteraselectioniscompleted.Iftheuserhascompletedaselectionbymistakethereisnoeasywayforhimorhertoundotheselectionorgobacktothepreviousstateofthesystem.IfaTVshowisselectedinthedisplaymenu,thecompletemenuwillbereplacedwithepisodesfromthatspecificTVshowandthereisnootherwaytoreturntothelistofTVshowsinthedisplaymenuexceptthanfortheusertogotobacktothemainmenuandselecttheTVshowbuttonagain.ThesameappliestotheExitVRexperiencebuttonthatwillimmediatelyclosetheapplicationwithoutanycontrolquestion.ThisproblemrelatestoNielsen’s(1995)heuristicsconsideringvisibilityofsystemstatus,usercontrolandfreedom,anderrorprevention.

Table5.Thesixproblemsofhighseverityfoundintheheuristicevaluation.

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Anotherhighseverityusabilityproblemisthatitistime-consumingandhardtofindaspecificepisodeofaTVshowinthedisplaymenu.Theepisodesarealldisplayedwiththesameimagesandthereisnocleardivisionbetweenthedifferentseasons.Undereachepisodeasmalltextisdisplayedandtheuserhastoturnhisorherheadtostartthescrollingoftheepisodestoreachmoreepisodes.Sincethetextisverysmallandthescrollingmakestheepisodeimagesandtextsflyinfrontoftheuserseyes,itishardtoreadwhichepisodesarecurrentlypassingby.Thiscausestheusertohavetoturnhisorherheadtostartthescrolling,stopitbyturningtheheadbacktothecentre,readwhichepisodesarecurrentlyinfrontofhimorherandthencontinuethescrollinganddothesameprocedureoveragainuntiltherightepisodeitdisplayedinfrontoftheuser.Thisisbothergonomicallyuncomfortableandrequiresmuchoftheuser’scognitiveabilitiesinfocusingonguessinghowfars/hehastoscrolltoreachthedesirableepisode.TheproblemrelatestoNielsen’s(1995)heuristicsaboutusercontrolandfreedom,errorprevention,recognitionratherthanrecall,andflexibilityandefficiencyofuse.

Thefifthusabilityproblemofhighseverityrelatestothefourthproblem.Non-ergonomicinteractionisrequiredfortheusertoreachhisorhergoal.Toopenthemainmenuorscrollthroughepisodesinthedisplaymenuitrequirestheusertoturnhisorherheadseveraldegreesfurtherthanwhatiscomfortabletodo.ThisproblemrelatestotheNielsen’s(1995)heuristicofflexibilityandefficiencyofuse.

Thefinalusabilityproblemofhighseverityisabuginthesystemdisplayingthewrongiconfortheplayandpausebutton.Mostvideoapplicationusesthesamebuttonforpauseandplayanddependingonwhatstatethevideoiscurrentlyin,theavailablefunctionalityoftheiconisdisplayed.Ifthevideoiscurrentlyplaying,thebuttondisplaysapauseiconandthereversedifthevideoispaused.Thiscouldconfusetheuserandcausehimorhertomissthefunctionalityofthebutton.TheproblemrelatestotheNielsen’s(1995)heuristicsconcerningconsistencyandstandards,anderrorprevention.

Theproblemsofmediumseverityarethatinformationrequiredfordecisionsisnotvisiblewhentheuserisinteractingwiththemenu.Ahelpfunctionisalsomissing.Furthermore,twoalmostidenticaliconsareusedforthefunctionalitytorewind10secondsandtoexittheVRexperience,whichcouldconfusetheusers.Anotherproblemisthattheiconslookverysimilartoaniconthatitusuallyusedforanundoorbackfunctionality,whichcancauseevenmoreconfusion.Moreover,theuserreceivesdifferentprogressfeedbackwheninteractingwithdifferentfunctionalityinthesystem.Duringmostinteractions,theuserwillseeacircularprogressbarshowinghowmuchisleftbeforetheselectioniscompleted.However,whentheuserplacetheheadgazecursoroverthefast-forwardingfunctionalitythefeedbackisonlyshowninthevideoandinthefunctionnamethatchangeswiththeacceleratingspeed.Thefinalusabilityproblemofmediumseverityisthaticonsandexplainingtextsofthefunctionalityinthesettingsmenuarehardtounderstand.AcompletelistofalltheusabilityproblemsisavailableinAppendixE.

5.2 Interview result and analysis

Theaimoftheinterviewswastoresearchtheparticipants’previousexperience,behaviours,goals,andvaluesrelatedtoVoDservices.Asecondgoalwastoresearchtheirpreviousexperienceof,values,andexpectationsofVRinrelationtousingittoconsumevideocontent.Thefinalpartoftheinterviewswasaimedtoresearchiftheparticipantshadanypreviousexperienceofcontrollingasystemwiththeireyemovementsorheadmovementsandiftheyhadanyexpectationsofhowthatwouldwork.

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TheinterviewsrevealedthatfiveoutofsixparticipantshadbetweenthreetofiveyearsofexperienceusingVoDservices.NetflixwasthemostcommonlyusedVoDservicesinceallparticipantsclaimtheyhadorwascurrentlyusingtheservice.FiveoutofsixparticipantsmentionedtheyalsohadusedHBONordicandfouroutoffivehadusedViaplay.WhenaskedwhichtechnicalplatformtheyusuallyusedforVoDservices,theanswersvaried.Halfoftheparticipantsmentionedtheirlaptopandtheirsmartphone,whiletwooutofsixmentionedSmartTVs,AppleTVs,andtablets.OthertechnologiesmentionedbyindividualswereforexampleWiiU,PlayStationandaChromecastconnectedtoaTV.WhenchoosingatechnicalplatformforVoDusagehalfoftheparticipantsansweredthatitdependedonwhatwaseasierinthesituationandbasedontheircurrentlocation.AllparticipantssaidtheywereusingVoDservicesintheirownhomeandfouroutofsixclaimedtheyonlyusedVoDservicesintheirhomeandexclusivelyintheircouchorintheirbed.Twopersonsalsosaidtheyuseditduringtripsoratwork.FouroutofsixparticipantsclaimedtheymostoftenusedVoDservicesincompanyandhalfoftheparticipantssaidtheywereusingVoDservicesasasubstituteforlinearTV.Whenaskedhowtheparticipantsdecidedwhatcontenttowatchtheyoftenhadseveralfactorsinfluencingtheirchoiceofvideo.FouroutofsixsaidtheyusuallybrowsedintheVoDservice,checkingrecommendations,genres,ornews.Fouroutofsixalsomentionedthatitwasalwaysbasedonthesituation.Halfoftheparticipantsmentionedthattheirmooddecidedtheirpreferredcontentatthemomentwhileanotherparticipantsaidthatwhens/hehadtimetokill,thechoicewasalwaysmoviesandthatifs/hewaswatchingincompanywithsomeoneelseitalsoinfluencedthechoiceofvideo.HalfoftheparticipantsalsomentionedtheirTVshowaddictionandthattheyjustkeptfollowingtheirTVshows.Fouroftheparticipantsalsomentionedrecommendationsorwhattheyhadheardaboutfromfriends,bloggers,ormedia.ImportantfunctionalityinaVoDservicewasaccordingtohalfoftheparticipantstobeeasyandjustintuitivelywork.Fiveofsixparticipantsalsomentionedsortingthatisrelevantforthem.Emphasisedwasalsothepossibilitytosearchandfindwantedcontentinafastway.FiveoutofthesixrespondentsclaimedthattheywereeasilyaffectedbytheirsurroundingswhiletheywereusingVoDservicesandthattheywereeasilydistracted.ThetypicalusagescenariowasthattheparticipantscamehomefromworkandthensatdowninthecouchandcontinuedwatchinganewepisodeofaTVshowtheywerefollowing.TwoparticipantsclaimedthatwhentheyaretryinganewmovieorTVshowtheyusuallyjudgequitequicklyifitisgoodenoughtocontinuewatching.Withinabout20minutesorhalfoftheepisode,theywilldecideifthecontentisworthtocontinuewatching.ThereasonthemajorityoftheparticipantswereusingVoDserviceswerebecausetheywantedtorelaxanddisconnectfromtheirlivesforawhileandatthesametimegetentertained.Theywantedtobeimmersedintheexperienceandreallyfeelliketheyareexperiencingthestoryinthevideo.Requirementsfromtheparticipantstoreachthatfeelingtheyfirstofallneededavideowithagoodstoryandgoodvideoscreenquality,soundqualityandthateverythingjustworkswithoutdisruptions.Thepossiblybestexperiencehalfoftheuserscouldimaginewhilewatchingavideowasincinemaenvironmentwithabigscreen,goodsoundwheretheyarealoneanditisacalmandrelaxingenvironment.ThemostnormalthingthatfrustratedtheparticipantsinVoDservicewaswhentherewereproblemswiththeservicebuttheydidnotknowwhattheproblemwasorhowtorectifyit.Theywerealsofrustratedwhenitwashardtofindwhattheywerelookingfor.Thesecondpartoftheinterviewrevealeddataabouttheparticipants’previousexperience,opinions,andexpectationsofvideoinVR.First,theinterviewsrevealedthatfiveoutofsixparticipantshad

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previouslytriedanHMDwithasmartphonebutonlyveryshortly.Thegeneralexperiencetheyhadwasthatitwasexciting,cool,andfun.Theparticipants’opinionsonhowtheyfeltaboutwatchingavideoinVRwascollectedandfiveoutofsixhadapositiveattitudetowardsitandthoughtitcouldbeagoodandcoolexperience.WhenaskedtoimaginewhereandiftheywouldpossiblywatchavideoinVR,fiveoutofsixclaimedthattheywoulddoitathome.Moreover,twoparticipantsmentionedwatchingitwhiletravellingandonepersonsaids/hedidnotwanttodoitatall.ThesituationstheywoulduseitinwouldbesimilartonormalVoDserviceusage,includingatnightswhentheywantthetimetopassbyorbeentertained.FiveofsixparticipantsthoughtthatvideoinVRwouldhavetheadvantageofaddingtotheexperiencebymakingtheparticipantfeelmoreimmersedandeasierdisconnectedfromthesurroundings.OtheradvantagesthatwasmentionedwasthatitwouldbeluxurioustocreateapersonalizedspaceinVRwherethevideowatchingwouldoccurandthatitwouldbeconvenientandnicetowatchavideoinbedwithoutnecessaryneedingtohaveaTVinthebedroom.ImaginednegativeaspectsofwatchingavideoinVRwas,forexample,thesocialaspectthatwouldbehardwhenthepersonwaswearingtheHMD,orthattheHMDwouldbeergonomicallyuncomfortableorthatitwouldbeanuncomfortablefortheeyes.Twoparticipantsalsomentionedthatthevideomightnotbesuitableforchildrenorpeoplewithdisabilitiessincethevideomightget‘tooreal’.WhenaskedwhattheywereexpectingaUItolookinVRtheymentionedthatitprobablylookslikeanormalUIbutfloatingintheairandtheywouldprobablycontrolitwithsomekindofhandhelddevice.Noneoftheparticipantshadevertriedcontrollingasystemwitheyemovementsorheadmovementsbeforeandgenerallytheyhadnoideahowitcouldpossiblywork.

5.3 Usability test result and analysis

Thissectionpresenttheresultandanalysisfromthetask-basedscenariosandthefollowinginterviewintheusabilitytest.Whendatathatisnotsymmetrical,liketasktimesarebeinganalysed,themeancanbeheavilyinfluencedbyafewextremedatapointsandtherefore,isnotaqualitativemeasureofthemiddlevalue(Sauro&Lewis,2012).Themedianthenprovidesabetterideaofthemosttypicalvalue.Therefore,themedianvalueofthetasktimesisusedfortheanalysis.ThefirstscenariowasdirectlyaftertheparticipantsputontheHMDsandenteredtheapplication.Theywereaskedtoexplore,sharetheirfirstexpressions,andtellwhattheythoughttheywouldbeabletoaccomplishwiththeapplication.Thetimetheyspentexploringuntiltheyseemedtobesatisfiedanddonevariedbetweentwotofiveminutesbutthemajorityoftheparticipantsspentaboutthreeminutesbeforetheyshowedsignsofbeing‘done’withthetask.Sinceitwasascenariowithataskwithnorightorwrongorcompletionratesthemostinterestingdatawasfirstimpressions,howmuchofthefunctionalitytheparticipantsfound,andhowfastandwelltheyunderstoodtheinteractionmethod.Alsoerrors,recovery,andgeneralcommentsduringthescenariowerevalued.Thefirstimpressionswhenenteringtheapplicationwerealmostexclusivelysmilingfacesandtheparticipantsexpressedfeelingamazed,surprised,happy,andoverwhelmed.Whentheystartedexploringtheapplicationseveralparticipantsshowedcuriosity,concentration,andtheywereoftensurprised.Oneoutoftheparticipantswasnotablyscepticalabouteverything.Quantitativedatawasgatheredregardingtheamountofthesixinformationareasavailableintheapplication(seeSection4.1)andhowmanywasdiscoveredbytheparticipantsduringthefirstscenario.Noparticipantdiscoveredalltheareasduringthescenariobutfiveoutofsixparticipants

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discoveredthedisplaymenuandfouroutofsixdiscoveredtheplaymenu.Halfoftheparticipantsfoundthemainmenuandtwooutofsixfoundtheinformationarea.Onlyoneoutofthesixparticipantsfoundthesettingsmenu.TheparticipantswereonlytoldinthebeginningoftheinterviewbeforethetesthowtheinteractionwouldworkinasimplewaythattheywouldcontroltheUIwiththeirheadmovementsbutthinkitwastheirgazethatwouldcontroltheUI.Outofthesixparticipants,onlyoneparticipantwasnotabletounderstandhowtointeractwiththeUIduringthefirstscenario.Themediantimetounderstandtheinteractionmethodofheadgazewas55seconds.Generalfindingsincludedthattwooutofthesixparticipantsaccidentallyexitedtheapplicationwithoutknowingthattheydiditandtheapplicationhadtoberestarted.Amajority,fouroutofsix,participantsdidnotturntheirheadgazefarenoughtothesidesandupanddownfortheinformationtoappearandtherefore,missedcontent.Oneparticipantclaimeds/hewasexperiencingsimulatorsicknesswhenmenusappearedinfrontofhimorherandwhenthescrollinginthedisplaymenustarted.Onepersonhadproblemsunderstandingwhathappenedwhens/hewasinteractingwiththebuttonsinthesettingsmenu.Furthermore,twopersonsexpressedthatthescrollingfeatureinthedisplaymenuwas‘volatile’and‘ponderous’whenthecontentwasmassive.Thesecondscenariowasfortheparticipantstoimaginethattheywouldliketofindthetitleofthevideocurrentlyrunningonthescreen.Thiswasconsideredtobefairlyeasybyfiveoutofsixparticipantsthatfoundthetitlewiththeshortmediantimeof6seconds.However,twooftheparticipantsneededaminutetofinditandonepersonwasnotabletofinditatall.Theparticipant,whodidnotfindit,actuallyfoundthetitleinformationbutdidnotrealisethattheinformationwasthevideocurrentlyplaying,butthoughtitwasanothersuggestedvideo.Thatparticipantgaveupafters/hehadbeensearchingfortheinformationfor90seconds.Laterduringtheotherscenarios,theparticipantrealisedtheinformationdisplayedwasaboutthevideocurrentlyplayingonthescreen.Oneparticipantaccidentallyexitedtheexperiencewithoutbeingawareofwhytheapplicationcloseddown.Twooutofsixparticipantswereexpectingtheinformationtoappearonthevideoscreenandfirstlookedthere.Moreover,halfoftheparticipantsalsoturnedtotherightbeforetheyturnedtotheleftwhensearchingforit.Thethirdscenariowasfortheparticipantstoimaginethattheywouldliketostartanothervideo.Thiswaseasytotheparticipantsandallwereabletofindandstartanothervideoandwithinthelowmediantimeof9seconds.Theparticipantswentstraightdowntothedisplaymenuandchoseavideodirectly.Oneoftheparticipantsstartedavideobutwasnotsureifs/hesucceededtoreachthegoalsos/helookedtothe‘informationarea’toconfirmthattherightvideowasselectedandhadstartedrunning.Thefourthscenarioencouragedtheparticipantstofastforwardinthevideo.Thiswasalsoobservedtobeeasyfortheparticipantsandallwereabletoperformthetaskwiththemediantimeof11,5seconds.Smallnoticedproblemswerethattwoparticipantshadproblemsopeningtheplaymenuonthefirsttryandaccidentallyopenedthedisplaymenuinstead.Theerrorwasveryeasilyandquicklyrecoveredfromandnoparticipantsmentioneditasaproblem.Fouroutofthesixparticipantsneededextratimetorealisethattheactionwassuccessfulandwasnotablyconcentrated.Theautomaticallyacceleratingspeedofthefastforwardingbuttonwasexperiencedbytwousersas‘smart’andbyoneasfrustratingsincethepersonlostcontrolandwantedtocontinuewithacertainspeedforalongertime.Thefifthscenariotestediftheparticipantswereabletopausethevideothatwascurrentlyplaying.Thiswasalsoobservedaseasyandalltheparticipantswereabletoperformtheactionwiththemediantimeof5seconds.Theparticipantthatneededthelongesttimetocompletethetaskwas

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confusedbythebugintheapplicationdisplayingtheplaybuttoninsteadofthepausebuttoneventhoughthevideowascurrentlyplaying.Theotherparticipantsdidnotevennoticethatthewrongiconwasdisplayed.Thesixthscenariowasfortheparticipantstostartthevideoagainandallparticipantseasilyperformedtheactionwiththeexactsamemediantimeof5seconds.Manyexpressedhoweasythisactionwas.TheseventhscenariowasfortheparticipantstofindandstartthefirstepisodeofthefirstseasonoftheTVshowtheSimpsons.Thiswasthescenariowherethemostparticipantshadproblemstoreachthegoalofthetask.Attheend,fiveoutofsixwereabletoreachthegoalbutthemediantimewastwominutes.Theparticipantwhowasnotabletoreachthegoalgaveupafter90seconds.ThatparticipanthadthenselectedtheTVshowbuttoninthemainmenubutwasstrugglingtofindwheretogonextandcontinuethesearchfortherightTVshow,season,andepisode.Thatparticipantwantedtotrytoperformthetasklaterduringthelastscenarioofthetestwhens/hehaddiscoveredmoreabouttheapplicationbutthengaveupafterthreeminuteswhentryingtofindtherightepisodescrollingthroughthedisplaymenuwithalltheepisodes.Theparticipantexplaineds/hewasexperiencingsimulatorsicknessduetoallthescrollingandflyingobjects.Fiveoutofsixparticipantsstartedtheirsearchbyscrollingthroughthecurrentcontentinthedisplaymenu.OneparticipantselectedtheTVshowbuttonfromthemainmenuandthenturnedhisorherviewdowntothedisplaymenuandbefores/herealisedit,theparticipanthadselectedaTVshowbymistake.ThiscausestheapplicationtoreplaceallthecurrentlydisplayedTVshowsinthedisplaymenuandinsteaddisplaytheepisodesoftheselectedTVshow.Theparticipantwasconfusedandtriedtofindanundoorbackfunctionalitytogobacktothepreviousview.Inthesearchs/hediscoveredtheiconusedtoexittheVRexperienceinthemainmenuandmovedtheheadgazeoverit,withthebeliefitwouldbeanundobutton.However,theparticipantrealisedlastsecondtheactionthebuttonwouldcauseandremovedtheheadgazefromthebuttonbeforeitwasselected.S/hecontinuedtosearchforanundobuttonintheplaymenuandtherefoundtheorangecircleinthemiddleandtriedtoselectit.Finally,theusergotfrustratedandsaid‘HowdoIgetoutofhere?!Okey,Iamstuck!IguessIhavetostartalloverbyselectingTVshowsagain.’Threeoutofsixparticipantshadproblemsseeinghowtheselectionsinthe‘mainmenu’controlledthecontentinthedisplaymenu.OneparticipantfoundthebuttonforTVshowsinthemainmenubutcommented‘Oh,thislistwillbehugesoIwilltrytofindsearchinstead!’Fiveoutofsixparticipantshadproblemswhentheywerescrollingthroughthedisplaymenu.Theyhadtopausethescrollingandgointothecentreofthedisplaymenutobeabletoreadtheepisodesnamesandstatedthattheywerehavingtroubletoseewhattheywerescrollingpast.Halfoftheparticipantsscrolledpasttheepisodetheywerelookingforwithoutevennoticingit.Commentsofillustratingtheusersexperienceincluded‘OhmyGod–youhavetoturnsomuchtoscroll!’and‘Theremustbeasmarterwaytodothis?’.Oneparticipantalsohadtroublerealisinghowtostopthescrollingonceithadstarted.Anotherparticipanttriedtospeedupthescrollingbyinteractingwiththedisplaymenuprogressbarunderneaththedisplaymenu.TheeightscenarioaskedtheparticipanttofindtheTVshowMadMeninstead.Thiswasobservedtobeeasyandallparticipantswereabletocompletethetaskwiththemediantimeofnineseconds.Theparticipantsclaimeditwasasimpletaskandeasybecausetheyjustdidastheydidbefore.OnepersonneededalongertimetocompletethetaskandthiswassincethepersonspentthattimescrollingthroughthedisplaymenutofindtherightTVshow.

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TheninthandfinalscenariotheparticipantswerepresentedtowastocontinueexploringtheapplicationandfindasmuchfunctionalityaspossibleandtellwhattheythoughtallthemenuoptionsandUIelementswouldleadto.ThisscenariorevealedproblemsuserhadafterafewminutesofusingtheapplicationandhowwelltheyfoundandunderstoodeverythingintheUI.WhentwoofsixparticipantsstatedthattheyhadfoundeverythingtheythoughttherewastofindintheUI,theystillhadnotfoundthesettingsmenu.ThemoderatorthentoldthemtherewasstillanunexploredpartoftheUI.Asaresult,theywerethenabletofindthatmenuaswell.Fiveoutofsixparticipantshadunderstoodthemainmenuanditsfunctionalityexcepttheexitbutton.ItwasoneofthebiggestissuesintheUIandfouroutofsixparticipantshadnotmemorizedthefunctionalityoftheexitbuttoneventhoughtheyalreadyhadusedithoveredoveritbefore.Onepersonclaimeditwasthe‘backbutton‘eventhoughthepersonhadselectedthebuttonearlierduringthescenarios.Anotherpersonclaimedthattherewind10secondsbuttonintheplaymenu,withalmosttheexactsameiconastheexiticon,wasabackbutton.Fiveoutofsixparticipantsdidnotunderstandthechannelbuttoninthemainmenuuntiltheyreadthebuttonnamewhilehoveringwiththegazecursoroverit.Moreover,twooutofsixparticipantshadnotyetmemorizedwherethevideotitleandinformationwasdisplayedandwasremindedwhentheyweresearchingthroughtheUIandturnedtheirheadstotheright.AnotherinterestingobservationwasthatalltheparticipantstriedtointeractwithUIelementsthathadnofunctionality,suchastheorangebuttonsinthecentreofthesettingsmenuandtheplaymenualongwiththedisplaymenuprogressbar.Onlyoneparticipantunderstoodwhatthedisplaymenuprogressbarspurposewas.Anotherinterestingdiscoverywasthatalltheparticipantshadtroubleunderstandingthefunctionalityofthebuttonsinthesettingsmenu.Fouroutofsixparticipantskeptturningfunctionsonandoffseveraltimesandshowedhighconcentrationwhentheytriedtodiscoverwhichchangethebuttonselectionhadcaused.Halfoftheparticipantsfinally,understoodthefunctionalityofscreentypeandthebuttonscene.Moreover,twoparticipantsunderstoodthefunctionoftheleaklight.However,oneparticipantthoughtthebuttonchangedthecoloursettingsofthevideo.OnlyoneparticipantwasabletounderstandtheSFXbuttonthatturnedonandoffbuttonsoundeffectintheapplicationandtwoparticipantswereveryconfusedsincetheythoughttheywouldhavethreebarsasdisplayedintheiconwheretheycouldcontrolthesoundofthevideo.Onepersonhadnotfiguredouthowtoentertheviewmodeandwasaskingabouthowtoturnoffallthefunctionalityandhavealargerscreen.AnotherparticipantwasannoyedbyhoweverylittlemovementoftheheadmadethewholeUImoveandsaids/hewantedtoturnthatoffwhilewatchingamovie.Anotherparticipantclaimeds/hehadtroubleseeingwhichfunctionalitywasactivatedandwhichwasnot.Moreover,anothercommentedontheinteractionmethodandsaid‘Youhavetogothroughquitealotoftroubletointeractwithyourheadlikethisjusttostartavideo.’AnotherobservationwasthattwooutofsixparticipantskeptholdingtheHMDwiththeirhandsandchangingthehandtotheotherwhentheygottiredinonearm.TheyclaimedtheHMDwasheavyandpressingontheirnose.AlltheparticipantswerenotedtohaveachangeinvoicefromanormaltonetoamorenasaltoneconfirmingthepressuretheHMDscausedontheirnoses.Afterthetest,theparticipantswereaskedseveralquestionsabouttheirexperience.Generally,theysaidthattheexperiencewascool,impressive,funandthattheywerefeelingimmersed.Buttheyalsosaidthattheywerefeelingstressandconfusion.ThreeoutofsixparticipantsclaimedthattheythinkwatchingavideowithanHMDinVRwouldgiveabetterexperiencethananormalTVscreen.Oneoftheparticipantswhothoughtanormalscreenprovideabetterexperiencesaiditwasbecauseofthelimitedresolutionandthatthedistancefromthevideoscreenwasnotoptimalintheprototype.Theotherparticipantssaidthats/hesawnoextrafeatureintheprototypethats/hewouldnotbeabletoexperiencewithanormalTVscreen.Forthelastparticipant,itdependedonthe

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videocontent.S/heclaimedthatactionornaturevideoswouldbebetterwithanHMDinVRbutothercontentwouldbebetterexperiencedonanormalTVscreen.ThethingsthattheparticipantswishedtoexperienceinVRincludedmovies,places,andgames.Oneparticipantwasverypositiveandclaimed‘This!Exactlythis–justmoviesandnothingelse!’.Moreover,thenavigationoftheapplicationwasexperiencedbothpositivelyandnegatively.Thenegativeexperiencesparticipantssharedwasthatitfeltabit‘annoying’touseforlongerperiodsoftime.Onepersonalsomentionedthats/hethoughtitfeltlikes/helookedverydumbwhilewearingtheHMDandinteractingwiththeVRGUI.Twoparticipantsclaimedtheywouldhavepreferredtousetheinteractionmethodincombinationwithahandheldcontrolwhileoneparticipantclaimeds/hefeltnoneedofanyothercontrolandwaspositivelysurprisedbythefact.Oneparticipantsaiditwaseasyandintuitivetouseandnofunctionalitywasmissingwhileanotherparticipantclaimeds/hewasmissingasearchfunction.Moreover,oneparticipantlikedtheideabehindtheinteractionandtheanimationofthemenuswhentheyappeared.Whenaskediftheparticipantsfeltliketheycouldcontroleverythingtheywantedtocontrol,threeoutofsixclaimedtheycouldbutsaidthatthesettingsmenuwasexperiencedascomplicated.Twooftheparticipantswhoanswerednosaidthattheyhadtroublewiththesettingsmenuandthattheyweremissingfeedbackiftheyhadperformedaselectionornot.Anotherparticipanttoldthats/hehadtotrymanytimestosucceedwithaselectionandthatthereweremanyaccidentalselectionsthatoccurred.Thedwelltimethatwasrequiredfortheparticipantstoperformtheselectionswasingeneralexperiencedasagoodamountoftime.Oneparticipantsaidthatthetimefelttoofastinthebeginningbutthenfelttooslowassoonasthepersonhadrealisedhowtheinteractiontechniqueworked.Also,anotheroneclaimedthats/hewouldprobablyhavewantedthedwelltimetobeshorterwhens/hegotmoreexperiencedusingtheinteractionmethod.Oneparticipantmentionedthatthedwelltimeforselectingamoviewasperfectbutforthebuttonswithunknownfunctionalityitwastoofastanditcausedastressfulsituation.Onepersonclaimeditwasaproblemwhens/hewasjustlookingatthedifferentmoviesandaccidentallyperformedaselectionofamovie.Whenaskedifsomethingwashardtounderstand,see,orperformfouroutofsixparticipantsmentionedthesettingsmenuandthefunctionalityinit.Moreover,twoparticipantsmentioneditwashardandtime-consumingtofindaspecificepisodeofaTVshow.Oneparticipantdescribedthats/hehadnotfoundabuttonforvolumecontrolandonestatedthatitwashardtoseewheres/hewasatthemomentandthats/hewasforcedtogobackandredothingsmanytimes.Anotherparticipantmentionedtheresolutionandthatitwashardtoreadtheepisodenameswhiles/hewasscrolling.Finally,anotherparticipantdescribedittobefrustratingtryingtointeractwiththeorangebuttoninthecentrethatwasnotpossibletointeractwith.Whenaskedifsomethingwaseasytounderstand,see,orperformhalfoftheparticipantsmentionedplayingandpausingavideo.Oneparticipantdescribedthatitwaseasytofindinformationaboutthevideothatwascurrentlyplayingandanothermentionedperformingselectionssincethecircularprogressbarwasveryeasytounderstandandfollow.Anotherparticipantmentionedthatitwaseasytoseethevideosinthedisplaymenuandanotherpersonmentionedthatthemainmenuwaseasytouse.Twooutofsixparticipantsweresurprisedbythequalityofthevirtualworld.Otherthingsthatsurprisedtheparticipantswerewhentheyfoundnewfunctionalityorwhentheybyaccidentexitedtheexperience.

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HalfoftheparticipantssaidtheydesiredandwasmissingasearchfunctionalityintheVRGUI.However,twoparticipantssaidtheywerenotmissinganyfunctionalityatall.TwopersonsmentionedthatitwouldhavebeendesirablewithanotherwayoflistingtheepisodeswithaclearseparationbetweentheseasonsofaTVshow.Onepersonclaimeds/hefeltlimitedintheways/hecouldinteractwiththesystem.S/hesaid‘SometimesIfeellimitedusingatouchscreenbecauseIcannotrightclickasIusuallydowhenIamusingacomputermouseortrackpad.HereIhaveevenmorelimitsanditmakesmefeelalittlehandicapped.ItfeltlikeIhadlostmyarms!’ThingsthatfrustratedtheparticipantswereforexamplethattheHMDwasheavy,ittookalongtimetoreachcertaingoalsintheVRGUIandthattherewasnosearchfunctionality.Halfoftheparticipantsmentionedthatitwasalotofblackspacearoundtheminthevirtualworldandthattheywouldhavepreferredtohavethevideoscreencoveringthefullvisualspace.Onepersonmentionedthatitwasfrustratingtonotknowwhatallthefunctionalitywasandhowitworked.AnotherpersonmentioneditasdisturbingthattheHMDwassosensitivetoeverylittleintendedorunintendedmovementtheparticipantdidwithhisorherhead.Whenaskedwhatcouldhaveimprovedtheexperience,halfoftheparticipantsonceagainmentionedhavingthevideoscreencoveringthewholevirtualenvironment.Anotherparticipantmentionedbetteradoptionofthedistanceofwherethedisplaywasshowntotheparticipant.Moreover,onepersonwishedforaclearerVRGUIsos/hecouldmoreeasilyunderstandallthefunctionalityandaclearerfast-forwardingfunction.Oneparticipantalsowisheds/hedidnothavetoturnandreadtextstofindaspecificepisode.Furthermore,anotherparticipantdescribedadesiretohavemoreofafinishingtouchontheVRGUIelementstomakeitlookabitmore‘cool’andmore‘playful’.ThatpersonwouldhavelikedtheVRGUItolookabitmorehandmade,lavish,andpolished.WhenaskediftherewasanythingthatwouldhavemadetheparticipantschoosetowatchavideoinVRinsteadofonaregularscreentheyclaimedthattheywouldchooseitsinceitisconvenient,comfortableandalsoaddstotheexperience.Oneparticipantsaids/hewouldalwayschoosetheVRexperienceforvideowatchingandtwopersonssaidnothingcouldmakethemchoosewatchingavideoinVRinsteadofwatchingvideoonaregularscreen.Onepersonmentionedthatitwouldbeconvenienttobeabletowatchavideoundisturbedinaroomfullofotherpeopleandthatitwasreallycomfortabletobeabletodothatandtostillseeabigscreenandhaveagreatexperience.ThingsthattheparticipantsgenerallylikedabouttheVRGUIwerethedisplaymenuthatwasexperiencedasintuitivelyplacedandstylish.Furthermore,participantslikedtheinteractionmethodincludingthedwelltimeusedforselections.Oneparticipantevensaid‘thatyoucancontroltheUIwithonlythethought!Oritistheheador…howdoyouexplainit?’.Anothersaidthat‘Thedwelltimewasgreat!Youcouldeasilyseewhentheprogresscirclewasloadingandturnawayifyouwantedto.Thatwasreallygreat–Ithinkthatwasthebestpart!’Moreover,oneparticipantlikedthecoloursandtheiconsandanothermentionedthevideoscreenthatwaslooking‘cleanandstylish’.Anothermentionedthecrosshairusedforthecursorandsaidthatitwasdiscreetenoughtonotinterferewittheexperiencebutatthesametimevisibleenoughtobenoticedandused.Thingsthattheparticipantsdislikedwere,forexample,thesettingsmenuandthedisplaymenu.Thesettingsmenuwasexperiencedashardtounderstandandthedisplaymenuwasexperiencedasvolatile.OneparticipantmentionedhowitwashardtogetanoverviewofthemoviesandtheTVshowsandthatitwashardtoorientintheVRGUI.Anotherparticipantdescribedhows/hedidnotlikethatsomeUIelementswerenotpossibletointeractwith.Moreover,oneotherparticipantsuggestedthatthedwelltimeshouldhavebeenadaptedtodifferentlengthsfordifferentselections.Oneparticipantstatedthattheinteractiontechniquewasnotsustainableandwouldnotworkinthelongrun.S/hemeantthattheinteractionmethodwouldworkinthebeginningorafewtimesbutwhenusedondailybasesitwouldbetoodemandingtouse.

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TheparticipantswerealsoaskedwhattheywouldhavechangedtomaketheVRGUIeasiertouse.Twooftheparticipantsdescribedusinganotherinteractionmethodincludingsomekindofhandheldorhand-controlleddevice.Thiswhiletwoparticipantsmentionedaddingsearchfunctionality.Oneparticipantdesiredsomethingthateasierlinkedthesurfacestheparticipanthadtofindwhenperforminganaction.Moreover,oneparticipantalsomentionedaddingabackfunctionality.Finally,aparticipantsaids/hewantedalargerplaybuttoninthemiddleandthepossibilitytoturnofftherestoftheVRGUIwhilewatchingavideo.WhenaskedhowtheparticipantswouldhavechangedtheVRGUItomakeitmorefuntouse,halfoftheparticipantsmentionedthatthevirtualworldwasverydarkandmaybealighterenvironmentorthepossibilitytochangetootherenvironmentswouldhavemadeitmorefuntouse.Furthermore,oneparticipantsaidaddinggameelementstotheinteractionandcreatingmoreofanartisticexperiencewhileinteracting.Oneparticipantmentioneddisplayingvideosinagridoffivetimesfivewheredifferentrowscouldbeusedtosortdifferentvideosormaybedisplaythevideosinanothertypeofcircleawayfromtheuserinsteadofaroundtheuserinthecurrentversion.

5.4 Survey result and analysis

Withtheaimtoresearchtheusers’behaviour,preferences,andfrustrationsrelatedtoVoDserviceusagethesurveyrevealedUXdataofrelevanceforthespecificapplication.

Thefirstquestion,withsub-questions,wasaimedtoresearchthefrequencyofdifferentgoalstheusercanhavewhentheyarestartingaVoDservice.Differentscenariosofgoalswerepresented,andtheresponders’taskwastoanswerhowfrequentlythosegoalswerethereasontheystartedtheservice.Thealternativestheyhadtochoosebetweenwere‘never’,‘rarely’,‘quiterarely’,‘sometimes’,‘quiteoften’and‘often’.Chart1displaystheresultfromthefirstquestioninthesurveythatisexplainedinthefollowingparagraph.

Chart1.Resultfromthefirstquestionofthesurveyshowingtheamountofresponses(n=60)foreachfrequencyalternativeforeachdifferentgoal.

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ThefirstgoaltherespondentswasaskedtoanswerthefrequencyaboutwashowoftentheyopenaVoDservicewiththegoaltofindsomethingtowatchwhentheuserdoesnotknowwhattowatchinadvance.Outofthe60responders,18personssaidtheydiditsometimesand18personssaidtheydiditquiteoften.WhenaskedhowoftentherespondentsopenaVoDservicewiththegoaltofindsomethingtowatchwhentheyalmostknowwhattheywouldliketowatchinadvance,24personsansweredquiteoftenand18personsansweredsometimes.AnothergoalwashowoftentherespondentsopenedaVoDservicewhentheyknewexactlywhattheywantedtowatchinadvance.Outofthe60respondents,18personsansweredoftenand15personsansweredquiteoften.WhenaskedhowoftentheyopenedaVoDservicetocontinuewatchingsomethingtheystartedwatchedearlier,23personsansweredoftenand13personsansweredsometimes.ThefinalgoaltherespondentswereaskedaboutwashowoftentheyopenaVoDservicewiththegoaltocontrolifacertainnewvideoispublishedintheservice.Only4personsansweredoftenand19personsansweredrarelywhile11personsansweredsometimes.

Thesecondquestioninthesurveyaskedtherespondentstorankoutofthreealternatives,whichwasthemostimportantinaVoDservice.Thethreealternativeswere‘ToeasilyandquicklybeabletofindthevideosIknowinadvancethatIwouldliketowatch.’,‘TogetinspiredandeasilyandquicklyfindvideoswhenIdonotknowinadvancewhatIwouldliketowatch.’and‘ToeasilyandquicklybeabletocontinuewatchingwhereIstoppedwatchinginavideoduringmylastuseoftheVoDservice.’.Thisquestiononlyhadminordifferencesinnumbersandnoclearpattern.Outofthe60respondents,22personsrankedthealternativetocontinuewatchingasnumberoneand22personsrankedtoeasilyfindavideowhentheyknowinadvancewhattheywouldliketowatchasnumbertwo.Atotalof27personsrankedthealternativeofgettinginspiredasnumberthreeinthepriority.However,itturnedouttobeamisunderstandingofhowtherankingscaleworkedandtherefore,thenumbersmightbemisleading.Somemighthaverankedtheirmostimportantasnumberthree,andothersmighthaverankedthemostimportantasnumberone.Therefore,thisresultisexcludedfromtheanalysisandnotvisualised.

Thethirdquestionwasdesignedwithacommentboxforopenanswers.Thequestionwas‘WhenIknowexactlywhatIwouldliketowatch,thenIusuallyfindthevideoby…’.Atotalof59responseswerecollectedsinceonerespondentdecidedtonotanswerthequestion.Theresponsesweresummarizedinadocumentandanalysedtofindpatternsofsimilaritiesinanswerstodiscoverpatterns.Somerespondentsansweredseveralwaystheyusuallyfoundthevideo.Amajorityoftherespondent,44persons,answeredtheywoulduseasearchfunctionality.Withinthatgroupofrespondents,somewrotethattheywouldsearchforthetitle,otherwrotethattheywouldsearchforthegenre,andotherswrotekeywords.AmongtherestoftheresponseseightwasrelatedtojustfindingitdirectlyonthestartpageoftheVoDserviceandfivepersonsansweredtheywouldlookforitbygenre.Chart2visualisetheresultofquestiontwofromthesurvey.

Chart2.Resultfromsurveyquestionthreeshowinghowtherespondents(n=59)prefertofindavideowhentheyknowexactlywhattheywouldliketowatch.

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Thefourthquestionwasaquestionwithmultiplechoiceswheretherespondentswereaskedtoanswerwhatknowledgetheyusuallyhavewhentheyalmost,butnotexactly,knowwhattheywouldliketowatch.Respondentscouldselectseveraloptionsfromalistoraddtheirownunder‘other‘iftheyusuallyhadinformationthatwasnotinthesuggestedlistofalternatives.ThecompletelistofalternativesispreviouslydescribedinSection4.4.AsChart3shows,outof60respondingpersons,54personsoftenknewwhatorwhichgenresthevideoshouldbe.Otherpopularresponseswerethat24oftherespondersusuallyknewwhichfeelingthewantedthevideotogivethemand23personsknewwhichvideoorvideosthevideoshouldbesimilarto.Furthermore,22oftherespondentsalsousuallyknewwhichactorsshouldbeinthevideo.

Thefinalquestionofthesurveywasdesignedwithacommentboxtocollectqualitativedataandopinions.Thequestionwas‘This(ifanything)frustratesmewhenIuseVoDservices(exceptinternetconnectionproblemsandthevideoofferingintheservice).Outofthe60participants,

Chart3.Resultfromsurveyquestion4showingtheinformationusersusuallyhavewhentheyalmostknowwhattheywouldliketowatch.

Chart4.Resultfromsurveyquestionfive,showinguserssourceoffrustrationduringVoDusage.

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only33responseswerecollected.Severaldidnotansweroranswered‘nothing’andsomeansweredthingsrelatingtotheexceptionsofthequestion.Theseanswerswereexcludedfromtheanalysis.Outofthe34responses,sevenpersonsansweredthatnotbeingabletofindsomethingtowatchorhavingtoscrollthroughalotofcontentwasthemostfrustratingthing(seeChart4).Thiswhilesixpersonsansweredissuesregardingthesubtitlesandthesettingsofthem.Sixpersonsalsomentionedbadrecommendationsintheservice.Fourpersonsanswereditbeinghardtofindthewaybacktosomethingtheyalreadystartedwatching.Otherlessfrequentresponsesincludedabadoverviewofcontent,theautostopfunctionality,thatitwashardtoreachinformationaboutavideo,countryrestrictionsincontentanddifferenttypesofUIkeyboardsthatwerehardtouse.

5.5 Comprehensive analysis

Theaimofthissectionistodescribethecomprehensivefinalanalysisprocedureandhowthedifferentdatawascomparedandanalysedtogether.Thegoalofthestepwastofindpatternsinthedataandcreategroupsbasedonthefoundpatterns.Abottom-upapproachwasusedwherethedatawasfurtherexploredtodiscovernaturalgroups(Goodmanetal.,2012).First,eachmethod’sresultdatawasanalysedindividuallyandthencomparedandanalysedcomprehensively.

5.5.1 Identifying the users’ goals, needs, behaviours, preferences, and context of use

TheaimoftheresearchwastocreateabetterunderstandingofhowVRGUIscontrolledbyheadgazeshouldbedesignedforqualitativeUX.Furthermore;theresearchwaslimitedtotheapplicationofVoDservices.SincequalitativeUXisdefinedasthefulfillingofusers’pragmaticandhedonicgoals,oneimportantpartoftheanalysiswastoidentifythosegoalsandothersubjectiveaspectsinfluencingtheusers’experience.Therefore,thefirstpartoftheanalysisfocusedonidentifyingusers’goals,expectations,needs,behaviours,preferences,andcontextofuse.TheinterviewsrevealedthatparticipantsaremostoftenusingVoDserviceswiththemotivationandhighergoalofrelaxing,disconnectingfromtherealworld,andtogetentertained.Theseareinterpretedasthehedonicgoalsoftheusers.Thepragmaticgoalsofhighestpriorityincludedbeingabletocontinuewatchingavideowheretheusershadpauseditduringtheprevioususeoftheserviceandtoeasilyfindspecificvideostheusersknewbeforehandthattheywantedtowatch.Secondarypragmaticgoalsweretofindavideowhentheusersalmostknewwhattheywouldliketowatchandtofindvideoswhentheydidnotknowbeforehandwhattheywantedtowatch.ThethreehedonicgoalsandthethreepragmaticgoalsofhighestpriorityisvisualisedinFigure11.

Figure11.Theusers’pragmaticandhedonicgoalswhenusingavideoondemandserviceinvirtualreality.

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ExpectationsofvideoinVRincludeanevenmoreimmersiveand‘cooler’experienceandthattheusereasilyforgetsaboutthesurroundings.Furthermore,manyareconcernediftheexperiencewillbecomfortable,bothfortheeyesandalsoergonomicallyonthehead.Moreover,thereisageneralconcernof‘lookingdumb’whilewearingtheHMD.ThismaybeconnectedtotheimagetheusershaveofstandingwiththeHMDandwavingtheirarms.Inthevirtualworld,manyarenotsureexactlywhattoexpectwhichmakesthemcurioussinceitissomethingnewandmostcanonlyvisualiseaVRGUIsimilartoanormalGUIbutfloatingintheairinfrontofthem.Mostalsoimaginethecontroltobemadewithahandhelddevice,probablybasedonpreviousexperienceofhowUIsusuallyarecontrolledandmaybealsosincetheHMDshavemostlybeenmarketedforgamingpurposes.Thephysicallocationwasanalysedtomostlikelybeintheusersownhome,intheircouchortheirbed.Alsotravelingbycar,train,andairplanecouldbepotentiallocationsforusage.Thesituationisusuallyatnight,afterworkwhentheuserswanttorelaxandthinkaboutsomethingelseorwhentheyaretravellingandwanttimetopassby.Manyusersareimpatiencetofindwhattheyarelookingforandgetannoyediftheyhavetoscrolltoomuch.Sincethecontextofuseisusuallyafterworkatnight,manyusersareexpectedtobetiredandonlywillingtouseminimalefforttoreachtheirgoal.Manyusersarealsoeasilydistractedandwanttogetentertainedandimmersedasquicklyaspossible.Thebestvideowatchingexperienceiswhentheuserisaloneinacalmandrelaxingenvironmentwithabigscreenwithgoodqualityandgoodsound.Preferencesforfindinginformationincludeusingsearchfunctionalityandeasyfindvideosbasedongenres,feelingthevideoleadto,similarvideosandactorsinthevideo.Themostfrustratingscenariototheusersiswhenitishardtofindthevideotheyarelookingfor.

5.5.2 Analysis of the discovered user experience problems

ThesecondpartoftheanalysiswastoanalysetheUXproblemsfoundinthedatafromtheheuristicevaluation,interviews,usabilitytests,andsurveys.Thebottom-upapproachwasusedtodiscoverpatterns.GlobalUXproblemscounteractingwiththepragmaticandhedonicgoalsoftheusersweretheproblemswheremostfocuswasplaced.ThemajorityoftheUXproblemsdiscoveredseemedtorelatetothefactthatuserswerelackinginformationandcontrolintheVRGUI(seeFigure12).SeveralreasonswerefoundtowhytheywerethebigUXproblemsoftheapplicationandtheyarefurtherdescribedinthefollowingparagraphs.Eventhoughtheyarelistedastwoseparateparts,theyarestronglyconnectedtotheusers.

Figure12.Userexperienceproblemdiscoveredpattern.

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ThefirstbigUXproblemoftheapplicationisthatusershaveashortageofinformation.Patternsdiscoveredinthedatarevealthatthisisbecausetheusersarenotpresentedwithenoughinformation,theinformationislocatedtoofaraway,itistoohardtofindandtoohardtounderstand.Theinformationintheprototypehasalimitedvisibility.Onlyoneoftheinformationareasintheprototypeisavailableatthetime.Forexample,whentheuserisexploringanewvideointhedisplaymenu,s/hecannotseetheinformationareatotherightofthevideoscreenwithinformationaboutthevideothatiscurrentlyrunningonthevideoscreen.Thisloadsthecognitiveabilitiesoftheuserssincetheyhavetokeepinformationintheirmind.Anotherexampleofthisisthattheexplainingtexttoeachbuttonoffunctionalityisonlyvisiblewhentheuserholdstheheadgazeoverthatspecificbutton.Furthermore,whenthetextisdisplayed,theuserhaslessthan2000millisecondstointerpretthetextanddecideifthebuttonisthedesiredactionbeforetheselectionoccurs.Iftheactionisnot,theuserthenhastoquicklyturnhisorherheadgazeawayfromthebutton.Anexampleofwhentheinformationistoofarawayiswhentheuseristryingtolookforaspecificvideoandtherefore,turntothemainmenu,selectforexampleTVshowsandthencannotseewheretocontinuelookingforthespecificvideo.ThissincethedisplaymenuisnotdirectlyinconnectionwiththemainmenuandtheusersconeoffocusisobservedtobeverylimitedandsmallduringtheinteractionwithaUIelement.Theuserhastofocusandconcentrateontheselectionitselfsincetheuserisrequiredtoretainwiththeheadgazecursoroverthebuttonfor2000millisecondsfortheselectiontooccur.Therefore,theuser’sconeoffocusisnotedtobeextremelylimitedtotheimmediateareaaroundtheUIelementinfocus.Anotherexampleofwhentheinformationislocatedtoofarawayiswiththemenusthemselves.Severaluserswereobservedtoturntheirheadsnumeroustimeswhenexploring,butnotfarenoughinorderforthemenustoappear.Twousersevenmissedthesettingmenuuntiltheyweretoldaboutitattheveryendoftheusabilitytest.Anotherexampleiswhenusersarefast-forwardinginavideoandtheactionrequirestheuserstokeeptheheadgazeoverthebutton,whichbythesametimeleavesthetimelineofthevideooutoftheusersconeoffocusandFOV.Theuserthenhasashortageofinformationthatmightberequiredfortheusertomakedecisionsduringtheinteraction,forcinghimorhertostoptheaction,controltheinformationandthengobackandcontinuetheinteractiontocorrecttheresult.Theseexamplesalsoprovethattheinformationistoohardtofind.AnexampleofthisiswhentheuseristryingtofindaspecificepisodeofaTVshowinthedisplaymenu.SincesomeTVshowshavemanyseasonsandepisodes,andtheyarealldisplayedinthesamemenuwithnodifferencebetweenthemexcepttheverysmalltitletextbelowthemandtheuserisrequiredtoscrollthroughthemtofindtheepisodeitturnsintoaverytime-consumingtask.Theuserscognitiveabilitiesarehighlyloadedsincetheuserwilltrytoreadthesmalltextswhilescrollinginordertostopthescrollingattherightmomentandselectthedesiredepisode.Moreover,theinformationistoohardtounderstandsincetheuseoficonsanddescribingtextdoesnotmatchwiththeuserslanguageconcerningNielsen’s(1995)usabilityheuristicsofmatchbetweensystemandtherealworldandconsistencyandstandards.Theresultoftheinformationbeinglocatedtoofarawayandbeinghardtofindisthattheusersarehavinganuncomfortableexperiencehavingtoturntheirheadsrepeatedlyandfurtherthanthecomfortable30horizontaldegreesaccordingtoChu’s(2014)recommendationspreviouslydescribedinSection2.3.Anotherpartoftheinformationproblemisthatinformationishardtounderstand.Severalusersdidnotunderstandnumerousiconsandtextsexplainingthefunctionalityintheapplication.

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Furthermore,thefunctionalitywasnotclearevenwhenthefunctionalitywasactivatedsincetheinformationwaslocatedtoofarawayfromtheuser’sconeoffocus.ThesecondmajorUXproblem,tightlyconnectedtotheinformationproblemwasthatusersdidnothavecompletecontrolovertheVRGUI.Thismostlyrelatedtotheinteractionmethod,sinceitisdesignedsoselectionsoccurautomatically,eveniftheuserisnotawareofitandonlyplacestheheadgazeoverabuttonbycoincidence.ThisisanexampleoftheMidastouchproblem,previouslydescribedinSection2.4.Sinceseveralaccidentalselectionsoccurredduringthetests,manyusersfindthemselvesdisorientedandnotcompletelyawareofthesystem’scurrentstate.Moreover,thisisalsotightlyconnectedtotheinformationproblemandhowtheuserhastomovetheheadgazearoundtothedifferentinformationareas,onebyone,tofigureoutwheres/heislocatedandwhatfunctionalityisactivated.Aspreviouslymentioned,thedwelltimebeforeaselectionoccursispredeterminedto2000millisecondsandtherefore,theuserdonothavemuchtimetoread,explore,andprocesstheinformationinfrontofhimorher.Thiscausesaverystressfulsituationwheretheuserisafraidtoexplorethecontentsinces/hedoesnotwanttocauseanyaccidentalchangesinthesystem.Connectedtothisisalsotheissuethattheuserhasnovisiblewayofundoingorgoingbackfromanaccidentalorunwantedselection.Sinceitisnotcompletelycleartotheuserwhats/hecaninteractwithandwhatwillcausechangestooccurinthesystemthisalsoaddstotheuserfeelingconfusedandstressed.Moreover,anotherexampleisthatwhentheuserselectsthebuttonforexitingtheexperience,thereisnocontrolquestionoranyadditionalstepbeforethewholescreenturnsblackandtheuserhastoremovethesmartphonefromtheHMDandstarttheapplicationagain.Allthisleavestheuserfeelinglikes/hedoesnothavefullcontroloverthesystem.Finally,theUXproblemsfoundwereanalysedinrelationtotheusers’goals,expectations,needs,behaviours,moods,preferences,andcontextofuse.Inorderfortheusertoaccomplishtheirhedonicgoalsoffeelingrelaxed,immersedandentertained,theexperienceoftheVRGUImustbesimple,funandstress-freewhentheyaretryingtoreachtheirpragmaticgoals.OnepartofthisiscreatingaVRGUIwithasystemarchitecturethatfocusesonmakingthemostimportantpragmaticgoalsoftheusereasyandquicktoreach.Thiscouldincludekeepingthepreviouslywatchedvideodirectlyonthe‘startpage’oftheapplicationinorderfortheuserstoeasilystartoffwheretheypreviouslystoppedwatchingavideothelasttime.Itcouldalsoincludekeepingsearchfunctionalitywithineasyreachandapossibilityforuserstosearchforvideosbasedongenres,feelingthevideowillleadto,similarvideos,andactors.Moreover,guidelinesdevelopedfromtheresultandanalysisoftheresearchisdescribedinthefollowingchapter.

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6 Suggested guidelines Theresearchquestionofthisthesisprojectwaswhataspectsshouldbeconsideredwhendesigningagraphicaluserinterface(GUI)invirtualreality(VR)-controlledbyheadorientationinput-foraqualitativeuserexperience(UX).Sincetheapplicationtheresearchquestionhasbeenlimitedtoisvideoondemand(VoD)services,theresearchhasalsofocusedongatheringUXinfluencingdataaboutVoDservices.Basedontheresultsandanalysisoftheresearch,previouslydescribedinChapter5,andwithrespecttothebackgroundliteraturereviewinSection2.7,sevensuggestedguidelineshavebeendevelopedandarepresentedinthefollowingparagraphs.Generally,itisrecommendedtoalwaysdesignGUIsfollowingusabilityguidelinessousersinaneasyandsatisfyingwaycanreachtheirpragmaticgoals.Atthesametime,thedesignoftheGUIshouldalsoallowtheusertofulfiltheusers’hedonicgoalsassoonaspossible.Thisincludeskeepingthepragmaticgoalsoftheusersachievablewithinasfewselectionsaspossibleandalsoeasytofind.ForaVoDapplicationinVRaccordingtotheresearch,thiscouldbetokeeppreviouslywatchedvideosonthestartviewoftheapplicationandasearchfunctionality,followingtheusers’needsandpreferences,wheretheycaneasilyfindthevideotheyarelookingfor.However,theserecommendationsarespecificfortheapplicationofVoDservicesandarenotthemainfocusofthisthesis.ThefollowingguidelinesaredevelopedfortheapplicationofVoDservicesbutarebelievedtobemoregenerallyapplicableforotherapplicationsandcontextsandtherefore,servetowardsansweringtheresearchquestioninabroadersense.

1.PlacethegraphicaluserinterfacesoitiscomfortabletoexploreandinteractwithInVRtheGUIhasunlimitedpossibleplacementsinthreedimensions.Whencomparedtodesigningfordigital2Dscreenswheretheuserusuallyisabletoseethewholescreenatonceandeasilygetanoverview,theusercannotusuallyseetheentirevirtualenvironmentatthesametime.Themaximumfieldofview(FOV)ofthehumanvisualsystem,aspreviouslyexplainedinSection2.3,isapproximately200degrees(Bowman,2004).Howeverinhead-mounteddisplays(HMDs),theFOVisabout94degrees(OculusVR,2015c).Userscanchangetheorientationoftheirheadstoexploremoreofthevirtualworld.AccordingtoChu(2014),users’canturntheirheadscomfortably30degreestotheleftandrightside,12degreesdownand20degreesup.Moreover,thedepthperceptionisalsoimportantinvirtualenvironments.Objectsshouldbeplacedatadistancebetween75centimetres(OculusVR,2015b)and20metersawayfromtheuser(Chu,2014).Followinganolderrecommendationfortheminimumdistance,MikeAlger(2015a)suggestsamaincontentzonethatisdisplayedwithin155degreeshorizontallyandatadistancebetween0,5metersto20metersawayfromtheuser(seepreviousFigure6inSection2.3).However,thereisadifferencebetweencontentandaGUI,andtherefore,thesedistancesuggestionsarereplaced.TherecommendationofplacementtomaketheUIcomfortabletoexplorefollowsthedegreessuggestedbyAlger(2015a),theminimumdistancesuggestedbyOculusVR(2015b)andthemaximumdistancesuggestedbyOculusVR(2015a).Thisleadstoarecommendedplacementwithin155degreeshorizontally,atleast75centimetresawayfromtheuserbutnotfurtherthanthreemetresawayinthevirtualenvironment.MoreimportantlyisthattheelementsoftheGUIthattheusershouldinteractwithorneedstoplacethegazecursorovershouldbekeptwithinthecomfortableinteractionzone.Thesuggested

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comfortableinteractionzoneisbasedontheideasofChu(2014)abouthowpeoplecancomfortablyturntheirheads.Thecentreofthezone,herereferredtoasthecentrepoint,iswheretheuser’sheadgazeisnaturallypositionedwhentheuserlooksstraightforwardwiththeheadinthemostcomfortablenaturalorientation.Surroundingthecentrepoint,thezoneisbasedon60degreeshorizontally,evenlydistributedtotheleftandrightsidefromthecentrepointand32degreesvertically,where12ofthedegreesaredownfromthecentrepointand20degreesareup.Furthermore,thecomfortableinteractionzonefollowsthesamedistancerecommendationsforthecomfortableexploringplacement(seeFigure13foravisualisationofthesuggestedcomfortableinteractionzone).

Whiletherecommendedcomfortableviewandcomfortableinteractionzoneisbasedonliteraturefromthebackgroundstudyofthethesis,theguidelineisaresultoftheresearchinthisthesis.Althoughtheguideline’snamefocusesoncomfortableexplorationandinteraction,thereasonstofollowitexceedssolelyergonomicandvisualcomfort.Severaloftheuserexperience,UX,problemsdiscoveredduringtheresearchthatleadtousers’shortageofinformationandcontrol(previouslydescribedandpresentedinSection5.5andFigure10),relatetoNielsen’s(1995)usabilityheuristicsaboutvisibilityofsystemstatus,usercontrolandfreedom,recognitionratherthanrecall,andflexibilityandefficiencyofuse.ExamplesincludedthatusersdidnotfindallpartsoftheVRGUIsincetheytendedtoturntheirheadsfarenoughinorderfortheVRGUItoopenupandbecomevisibletothem.SincethewholeVRGUIwasnotvisibleatthesametime,thecognitiveloadwasheavyandthiswhiletheusershadtochangetheorientationoftheirheadsinnon-ergonomicwaystointeractwiththeVRGUI.Iftheguidelineisfollowed,ithelpsuserstoeasilyfind,explore,andinteractwiththeVRGUIinanergonomically,visually,andcognitivelycomfortablewaywhilesupportingtheusertoreachboththepragmaticandhedonicgoals.Furthermore,itwillhelpuserstousetheHMDsincontextsweretheywanttolimitthemovementsrequired.Forexample,whentravelling,theymightsitnexttoanotherperson,whoshouldnotbebotheredwhentheyareinteractingwiththeVRGUIandalsotheusershouldnothesitatetousetheHMDoffearoflooking‘dumb’whileturninghisorherhead.

Figure13.Thesuggestedcomfortableinteractionzonevisualised.Thezoneillustrateswhereuserinterfaceelementsthatcanbeselectedorinteractedwithinavirtualrealitygraphicaluserinterfacecontrolledbyheadorientationinputandheadgazeshouldbeplaced.

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ThisguidelineiscloselyrelatedtothreeoftheguidelinespresentedinSection2.7.Theguidelinesitrelatestois‘Allowuserstobelazy’,’Use“magic”interaction’,and‘PlaceVRGUIatareasonableandcomfortabledistance’.Table1inSection2.7showsanoverviewdisplayingwhichliteraturedescribeandsupporttheguidelines.However,thisguidelineprovidesanew,andtotheauthor’sknowledgeunique,recommendationofacomfortableinteractionzonefortheheadorientationinputandheadgazeinteractionmethod.

2.PlacevisualfeedbacktoselectionswithintheimmediateinteractionareaTheinteractionmethodthatusesheadorientationinputtoprojectanapproximatedgazecursorinthecentreoftheuser’sFOV,hasinthisthesisbeenreferredtoasheadgaze.Eventhoughheadgazeiscontrolledbyhowtheuserturnshisorherhead,theuserexperiencesitasifthecursoriscontrolledbythedirectionoftheeyegaze.Oneillustratingexampleisthattheusercouldturnhisorherheadinacertaindirectionandthenexploretheareainthevirtualenvironmentwiththeheadorientationfixatedwhilerelocatingtheeyegazeonly.Thiswouldleavethecursorfixatedwhiletheuserexploresthesurroundingsbutsincetheuserexperiencesthats/heiscontrollingthecursorwithhisorhereyegazedirection,thismightnotbeconsideredasanoptionbytheuser.Therefore,theusertendstofocuswiththeeyegazeatthesamelocationwheretheheadgazeiscurrentlylocatedtomakesurethattheselectionofthedesiredfunctionalityiscompleted.TheeyegazeisalsonecessarytokeepnearbytheheadgazecursorfortheusertomakesuretheheadgazecontrolledcursorstayslocatedovertheUIelementtheuserwanttointeractwith.Sincetheuserisfocusingandconcentratingontheobjects/hewantstointeractwith,thesurroundingareaintheVRGUIbecomesoutoffocusandturnsnearlyinvisibletotheuserduringtheinteraction.Therefore,itisnecessarytoplacevisualfeedbacktoaselectionwithintheimmediateinteractionareawheretheuseriscurrentlyfocusing.Theapproximatedareawherethefeedbackshouldbeplacediswithinthedoublediameterofthecursorbeingused(seeFigure14).Thisguidelineisdevelopedbasedonresearchresultandanalysisinthisthesis.Duringtheresearch,severalparticipantsdidnotunderstandthefunctionalityofonandoffbuttonsintheVRGUIsincetheywerenotabletoseethechangethatoccurredwhentheyinteractedwiththebuttons.Furthermore,severalwerenotabletoreachtheirpragmaticgoalssincetheydidnotknowwheretocontinuetheinteractionwiththeGUIaftertheyselectedacertainbuttoninamenu.ThisleadtoashortageofinformationandcontrolpreviouslydescribedandpresentedinSection5.5andillustratedinFigure10.Furthermore,itrelatestoNielsen’s(1995)usabilityheuristicsaboutvisibilityofsystemstatus,matchbetweenthesystemandtherealworld,usercontrolandfreedom,errorprevention,recognitionratherthanrecall,flexibilityandefficiencyofuse.

Figure14.Theapproximatedarea,doublethesizeoftheheadgazecursor,wherethevisualfeedbackfromaselectionshouldbeplacedinorderfortheusertoseeit.Thefirstimagefromtheleftshowthecircularprogressbaroftheheadgazecursorduringaselectionandthesecondimageshowtheestimationofhowthesmallconeoffocusmakethesurroundingsblurrywhilethethirdimagehasmarkedtheareawherethevisualfeedbackshouldbeplacedinorderfortheusertoseeanddiscoverit.

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Iftheguidelineisfollowed,ithelpstheusertoeasilyseetheresultoftheiractionsandwheretocontinuetheinteractiontoreachtheirpragmaticgoals.

3.Keepinformationdenseareasinteraction-freeWiththeheadgazeinteractionmethod,theinteractionwithandselectionofaUIelementstartsassoonastheuserplacesthegazecursorovertheelement.Afterthegazecursorisplaced,theuserhasalimitedtimetodecideiftheselectionisawantedactionornotsinceapredeterminedgazetimewilltriggertheselectionoftheelement.Intheresearch,thiscausedseveralUXproblemssuchastheusersmakingaccidentalselectionssincetheywerenotfinishedwithinterpretingandunderstandingthefunctionalityaselectionoftheUIelementwouldleadto.Furthermore,thiscausedastressfulsituationwhereusersturnedtheirheadsfromelementtoelementsincetheywereafraidofstayingwiththeheadgazefortoolongandperforminganunwantedselection.Thislimitedtheircuriosity,madethemfeelstressedandseveraltimestheywerenotfinishedwiththeexploringoftheobjectsandelementbeforeaselectionhadoccurred.ThisisanexampleoftheMidastouchproblem,previouslydescribedinSection2.4.ThisUXproblemalsorelatestotheusernotrealisingtheycanmovetheireyegazewhilekeepingtheheadgazecursoratonespotintheVRGUI.Therefore,thedevelopedguidelinesuggeststhatinformationdenseareasshouldbekeptinteraction-free.IfthepartsoftheVRGUIthatcontainextensiveinformationandcontentiskeptinteraction-free,theuserwillhavetheopportunitytoexploretheinformationinarelaxingway,oneofthehedonicgoalswiththeuse,andthenbeabletointeractandselectacertaincontentwhens/heisready.Thesuggestedguidelineisthereforetomaintaininformationdenseareasinteraction-free.Ifthisisnotpossible,aninteraction-freeareashouldbeplacedintheimmediateareasurroundingtheelement.Specificallyforinformationdenseareasorareasthatareharderfortheusertounderstand,theyneedmoretimetointerpretandexploretheinformation.Tominimizethecognitiveloadoftheusertryingtointerpretandreadinformationwhilekeepingtrackofamovingprogressbarfortheselectionatthesametime,theareashouldbeinteraction-free.ThisrelatestoNielsen’s(1995)usabilityheuristicsaboutusercontrolandfreedom,errorprevention,andflexibilityandefficiencyofuse.

4.UsedwelltimesofvariouslengthsWithheadgazeinteraction,adwelltimeisusedtotriggerselectionsintheVRGUI.Intheprototypeusedforpartoftheresearch,thedwelltimeusedforselectionswasconstantacrossdifferentpartsoftheVRGUI.Relatedtoguideline3,theusersometimesneedmoretimetointerpretorexploretheinformationbefores/heinteractswithitandthesolutioninguideline3wastokeepinformationdenseareasinteraction-freebutanadditionalrecommendationcouldbetoconsiderusingdwelltimesofvaryinglengths.ByallowingthedwelltimefordifferentselectionsintheVRGUItodiffer,itcouldworktowardsimprovingtheusability,relatedtoNielsen’s(1995)usabilityheuristicsofusercontrolandfreedom,errorprevention,andflexibilityandefficiencyofuse.PartsoftheUIthatrequiremoretimetobereadorinterpretedbytheusershouldhavealongerdwelltimeforselections.Furthermore,thedwelltimecouldbeadjusteddependingontheusersknowledgeandexperienceoftheVRGUI.Anexperiencedusermightwantshorterdwelltimeswhileanoviceuserneedslongerdwelltimes.

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5.Avoidusingtime-limitedinformationInthetestedprototype,theVRGUIwaskeptminimalisticandneartotextfree.Iftheuserdidnotunderstandtheiconofabuttons/hewasrequiredtoplacethegazecursoroverthebuttoninordertoseetheexplanatorytextforit.However,thehoveringinformationwasonlyavailableforthelimitedtimebeforetheselectionwastriggered.Iftheuserwasunabletounderstandtheiconfromthebeginning,andthenmovedtheheadgazeoveritandwasnotabletofinishreadingthehoveringexplanatorytextwhilekeepingtrackoftheselectionprogressbar,s/heendedupselectingthebutton.Someuserstriedtopreventtheunwantedselectionbymovingtheirheadgazequicklyoverandawayfromthebuttontoextendthereadingtimetheywereoffered.Thiscausedtheuserstofeelstressed,confusedwhentheyperformedaselectionandwasnotevensurewhattheyhadselected.Furthermore,thequickrotationsformovingtheheadgazewasobservedasnon-ergonomicandtheuserswerenotablyconcentratedsincetheywererequiredtotrytoreadthetextwhilekeepingtrackoftheselectionprogressbar.Thedevelopedguidelineisthereforetoavoidtimelimitedhoveringinformation.Iftheusersarepresentedwiththeinformationwithouthavingatimelimitationtointerpretingit,thisisbelievedtoreducethestress,thecognitiveloadandfurthermore,thenon-ergonomicheadrotations.TheUXproblemsarerelatedtoNielsen’s(1995)usabilityheuristicsofusercontrolandfreedom,errorprevention,andflexibilityandefficiencyofuse.Iftheguidelineisfollowed,itwillreducethecognitiveloadoftheuserandallowastress-freeinteractionwhereundesiredselectionsareprevented.

6.NeverforceuserstointerpretinformationinmovementWhenusersareforcedtointerpretinformationthatiscurrentlymovinginfrontoftheireyes,itleadstoahighcognitiveloadwheretheyneedtobehighlyconcentratedandfocusedonthetask.Furthermore,thiscancausesimulatorsickness.Intheresearch,onlyoneoutofthesixparticipantsexperiencedsimulatorsickness.Eventhoughitwasnotrankedasacommonproblem,itisstillextremelynegativefortheUXandtherefore,consideredimportanttoreduce.Thisrelatestothepreviouslydescribedguidelineto‘Avoidrapidmovements,donotdropframesorloseheadtracking’inSection2.7.However,thisdevelopedguidelineextendstheguidelinetoavoidforcingtheusertointerpretinformationinmovement.TheUXproblemscloselyrelatetoNielsen’s(1995)usabilityheuristicofthevisibilityofsystemstatus.

7.UsestandardsandaffordancestominimizethecognitiveloadMinimalisticGUIdesignisatrendlimitingtheamountofinformationdisplayedtotheuser.Visualcluttershouldbeavoidedtominimizethecognitiveloadbutwhentoomuchinformationisremoved,hiddenoriconsaretoosimplified,thecognitiveloadoftheuserwillincrease.InGUIsforscreens,thisisofteneasilysolvedbytheuserhoveringtoseeanexplanatorytextorbytheuserclickingontheelementtoexplorewhatthefunctionalityofitmeans.However,sinceanundoorbackactionisnotaseasilyperformedinaVRGUIcontrolledbyheadgazeandsincethehoveringoveraUIelementthattheusercaninteractwithistimelimitedtothedwelltimefortheselection,theVRGUIisnotaseasyandquickfortheusertoexploreifthetheydonotunderstandthefunctionalityofaUIelementfromthebeginning.Therefore,thesuggestionistouseexplanatoryinformationoftheUIelementfunctionalitythatisasclearaspossibletotheuser,requiringaminimalcognitiveeffortfortheusertointerpret.Thisusuallyincludescleariconsandshortbutdescriptivetitlesforthefunctionality.Moreover,thisrelatestothepreviouslydescribedguidelineto‘Helptheuserbyusingaffordances’inSection2.7.

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7 Conclusion and discussion ThisfinalchapterwillpresentthemaincontributionsandimplicationsinSection8.1.Thefollowingsectioncontainsamethodologicaldiscussion.Section8.3presentssuggestedfutureresearchandthefinalsectioncontainsconcludingremarks.

7.1 Contributions and implications

Themaincontributionofthisthesisisthedevelopedguidelines;1.� Placethegraphicaluserinterfacesoitiscomfortabletoexploreandinteractwith2.� Placevisualfeedbacktoselectionswithintheimmediateinteractionarea3.� Keepinformationdenseareasinteraction-free4.� Usedwelltimesofvariouslengths5.� Avoidusingtime-limitedinformation6.� Neverforceuserstointerpretinformationinmovement7.� Usestandardsandaffordancestominimizethecognitiveload

Theycontributetoansweringtheresearchquestionofwhataspectsshouldbeconsideredwhendesigningagraphicaluserinterfaceinvirtualreality-controlledbyheadorientationinput-foraqualitativeuserexperience.Furthermore,theyleadtoanincreasedunderstandingofhowgraphicaluserinterfaces(GUIs),shouldbedesignedfortheapplicationofvideoondemand(VoD)services.Followingtheexpectedcontributions(previouslydescribedinSection2.8.2),ahigherunderstandingofthedifferentconceptsindividuallyhasalsobeenachievedsinceamajorityoftheguidelinesandtheanalysedresultsareapplicableforothercontextsandapplications.Theresultscouldberelevantforhowtousetheinteractionmethodofheadorientationinputinothercontextsthanvirtualreality(VR)andforotherapplicationsthanVoDservices.Furthermore,theguidelinescanbeapplicableforotherapplicationsinVRandsomeevenfortheuseofotherinteractionmethods.Moreover,AccedohasreceivedfeedbackontheirprototypeandhowtocontinuethedevelopmenttoimprovetheUXoftheGUI.Anunexpectedcontributionisthesuggestedterm’headgaze’fortheinteractionmethodthatusesheadorientationinputtoapproximateagazecursorinthecentreoftheusers’fieldofviewtouseforinteraction.Finally,thethesiswillcontributeasafoundationforfutureresearch.ThedevelopedguidelinescanbeusedforfuturedevelopmentofVRGUIscontrolledbyheadorientationinputor,ifrephrased,asheuristicsforUXtestingofVRGUIscontrolledbyheadorientationinput.ForthedevelopmentofVoDservices,theresultpresentingtheuserspragmaticandhedonicgoalsincludingtheirbehaviour,needs,preferences,andcontextofusecouldbeusedasageneralpersonatodeveloprequirementswhendesigningtheUI.Dorabjeeetal.(2015)claimthattherehasbeenalackoffocusontheanalysisofUIsforHMDs.Furthermore,Bowmanetal.(2004)statethatthereisalackofempiricalevidencefortheusabilityofvarioussystemcontroltechniquesfor3DUIs.OculusVR(2015b)claimstherearenotraditionalinputmethodsidealforVRandthatinnovationandresearchareneeded.Moreover,theusabilityofeyegazeasaninputmodalityremainsmarginal(Bazrafkanetal.,2015).Thisresearchhasaddressedallthoseshortagesandsincetheheadorientationandheadgazeinteractiontechniquedoesnotrequireanyadditionalinputdevice,otherthanwhatisalreadyavailableinallHMDsforheadtracking,theUXguidelinesforhowtodesignforandusethetechniquecouldincreasetheuseofit.Furthermore,itcouldincreasetheuseofHMDs.Simpleand

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inexpensiveHMDssuchasVRsetsusedwithsmartphonescouldbespreadandusedforseveralpurposes,suchaseducational,toagreaterextent.Iftheleadingexpertsknowledgecouldbesharedinavirtualenvironmenttopeopleallovertheworld,thiscouldhaveamajorimpactonthesociety.Furthermore,thisinteractionmethodusedtocontrolsystemsisofspecificvalueforpeoplewithdisabilities,prohibitingthemfromusingtheirbodiestointeractwithsystems.Thepossibleethicalconcernswiththisresearchareiftheresultsareusedtoimprovesystemsforotherapplicationofdoubtablenature.Possiblescenariosforthiscouldbeinsimulatorsformilitarypurposes.However,theresearchandresultsareprimarilyconsideredtohaveapositiveimpactonthesociety.

7.2 Methodological discussion

Theresearchdesignusedacombinationofaheuristicevaluation,interviews,usabilitytests,andasurveyandtheresultsfromeachofthemethodsweretriangulated.Sincetheresearchapproachhasbeentomainlygatherqualitativedata,trustworthinessisusedtoevaluateit.Thetrustworthinessofqualitativeresearchisbasedoncredibility,transferability,dependability,andconfirmabilityoftheresearch(Lincoln&Guba,1985).Credibilitycanbeestablishedbyprolongedengagement,persistentobservation,andtriangulation(Lincoln&Guba,1985).Theresearchwasprepared,conducted,andanalysedoveraperiodofabouttwomonths.Limitationsinresourcesandtimerestrictionsprohibitedalongerandmorecomprehensiveresearch.Moretimetoresearchthedifferentconceptsandtovalidatetheresultswouldhavebeendesirableinordertoachievehighercredibilityoftheresult.However,boththeinterviewsandtheusabilitytestsweresoundandvideorecordedsotheanalysisofthedatacouldbedetailedandcomprehensive.Moreover,thecredibilitycanbeconsideredasimprovedsincedatatriangulationwasusedintheresearch.Transferabilityreferstotheexternalvalidityoftheresultandwhetherthefindingsfromtheresearchcouldbeapplicableinothercontexts(Lincoln&Guba,1985).Thestudyandcontextforthestudyhavebeendescribedinadetailedandexhaustiveway.Itistheauthor’sbeliefthatthefindingsfromtheresearchcouldbeappliedinothercontextsbutonlypeoplewhowouldliketousetheresearchresultscouldtrulyvalidatethetransferabilityoftheresult.Dependabilitycanbeachievedifthefindingsareconsistentandcanberepeated(Lincoln&Guba,1985).However,people’sopinionsandknowledgealwayschangeandtherefore,thefindingscouldneverbeconsistenteveniftheresearchwasrepeatedwiththesameparticipants.Inordertoachievedependability,themethods,andthemethodologicaldecisionshavebeendescribedindetail.However,itisuptothereceivertodecideiftheresearchseemsdependableornot.Confirmabilityreferstowhetheraneutralapproachhasbeenfollowed,wherethefindingsarebasedontherespondentsandnottheresearcher’sbiasorinterest(Lincoln&Guba,1985).Thishasbeenachievedinthisthesissincetheresearcherhasbeenawareofanddescribedhowthiswasavoidedduringtheprocedureoftheresearchmethods.Furthermore,boththestepsoftheresearchmethodsandthecollecteddatahavebeendescribedindetailinordertoshowtheoriginsoftheresultsinatransparentway.Duringtheresearch,thereweredecisionsmadeandproblemsdiscoveredthatmighthavehadanegativeimpactontheresults.Theformulationofoneofthesurveyquestionswasnotdescriptiveenoughwhichledtoitbeinginterpretedinvariousways.Whenthiswasdiscovered,adecisionwasmadetoexcludetheresultofthequestionfromtheanalysis.

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Duringtheusabilitytests,thesoundfromtheprototypewasledtotheTVinorderfortheresearchertohearwhattheuserwashearingandthiscouldhaveaffectedtheUXnegativelysincethemostimmersiveexperiencewouldhavebeenfortheusertouseearplugs.Additionally,thesmartphoneintheHMDwasconnectedwithacabletotheTV,whichmighthavemadetheHMDfeelheavierandlessfreefortheusertocontrol.Thismightevenhavecausedtheuserstofeelmorelimitedintheirheadmovementsduringthetest.Asaconsequence,theanalyseddatausedtodevelopthefirstguideline,mightnotbereliableandtheguidelinemightnotbeasimportantaspreviouslystated.Toconfirmtheimportanceofthis,andtheothersuggestedguidelines,moreresearchisrequired.

7.3 Future research

ThisresearchhasfocusedontheUXofheadgazecontrolledVRGUIs.Researchlimitationshaveincludedtimerestrictionsandresourcesavailable.Thefirstsuggestionforfutureresearchisthereforetoexpandtheresearch.Thiscouldincludeusingadditionalresearchmethods,additionalusersinthetests,additionalprototypesorsystemsthataretested,andadditionalHMDsthatareusedforthetesting.Thequalityofthedatacouldbeimprovedwiththeuseofmoreadvancedtechnology,othersettingsforthetests,andmoreexperiencedresearchers.Secondly,anaturalstepincontinuingtheresearchinthisthesiswouldbetovalidateandrefinethedevelopedguidelines.Thiscouldincludedevelopingandtestingprototypesbasedonthesuggestedguidelines.FurtherquestionsremainingtobeansweredincludeiftheseguidelinesarevalidacrossdifferentHMDs,fordifferentapplicationsandforpeopleofallages,knowledgeandpreviousexperience.Oneofthepredictedmostcommonusecontextiswhentheuserislayingdowninbedandforthatspecificcontext,moreresearchisneeded.Moreover,theresearchhasonlytestedpeoplelivinginSwedenwithacertainculture.Theremightbelargeculturaldifferencestotakeintoaccount.FurthersuggestionsincludeexpandingtheresearchtootherapplicationsthanVoDservicestogainadditionalinsights.Moreover,theusageofHMDsshouldbeobservedinanaturalenvironmenttogainadditionalcontextualinsights.

7.4 Concluding remarks

Thisthesishasstartedtoanswertheresearchquestionofwhataspectsshouldbeconsideredwhendesigningagraphicaluserinterfaceinvirtualreality-controlledbyheadorientationinput-foraqualitativeuserexperience.OculusVR(2015b)claimsthereisnotraditionalinputmethodidealforVRandthatinnovationandresearchareneeded.Eventhoughthisthesiscontributestoasmallpartofthatresearch,thereisstillanabundantamountofresearchtobedone.Whenthisresearchstarted,severalHMDsforconsumerswerejustabouttobereleased,andnowseveralofthemarereleased.TherehasbeenasurgeinmediaaddressingeverythingaboutHMDsandVRforconsumersandithasbeenimpossibletoincorporateallthenewinformationinthisthesis.Ifthethesisresearchhadbeencarriedouttoday,largepartsofifwouldprobablyhavebeendifferentbasedontheincreasedinformationandresourcesavailable.WiththepredictedcontinuinggrowthinusersofandapplicationsforVR,togetherwiththeincreaseofHMDsontheconsumermarket,theneedforVRGUIsthatoffersqualitativeUXwillincrease.ThiswillhopefullypushtheresearchtocontinuealongthepathofthisthesisresearchandextenditevenfurthertoaddressVRGUIsforallkindsofusers,applications,andHMDs.

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Heuristic evaluation inspection questions (translated to English - original in Swedish)

1. Is it clear to the user what is happening in the system?2. Do the system use the users language in a natural and logical order? 3. Is it easy for the user to back or undo an action?4. Is the system consistent?5. Is the system preventing possible ‘wrong’ actions?6. Is the system helping the user so s/he does not have to keep information, interaction possibilities and choices in his or her

memory?7. Is the system adapted for both novice and experienced users so they can use it effectively?8. Do the system display more than relevant information in such a way that it makes it hard for the user to take in the

relevant information?9. Are error messages designed so the user understand what the problem is and how s/he can solve it?10. Is it easy to find the help function and does it focus on the tasks the user want to perform? Is it easy to overview and does

it list concrete steps?

Appendix A: Heuristic evaluation inspection questions

Interview questions (translated to English - original in Swedish)

1. How old are you?2. How long have you been using video on demand services?3. Which video on demand services have you used?4. Which kind of technology do you use when you use video on demand services today?5. In which situations do you usually use video on demand services?6. Where do you usually use video on demand services?7. Are you usually using video on demand services alone or in company with other people?8. How do you most often decide what you would like to watch?9. When you watch a video, what do you base your choice of platform and technology on?10. What functionality do you want to have in a video on demand service?

a) Is there something you feel like you are missing today?11. How does the surroundings and environment affect you when you watch a video?12. How does a typical video on demand usage look for you? Give an example!13. What aim do you have with using video on demand services? What do you want it to lead to?14. What, except a good video, do you think create a good video watching experience?15. When you use a video on demand service, is there any problem or frustration that you often have?16. What previous experience do you have with virtual reality?17. How do you feel about watching video in virtual reality?

a) Is there anything that would change your opinions?18. How (if at all) would you like to watch video in virtual reality?19. Where (if at all) do you think you would like to use virtual reality to watch video?

a) Why?20. I which situations (if at all) do you think you would use virtual reality to watch video?

a) Why?21. Describe ways you think that virtual reality could add to your video watching experience (if any).22. Describe potential negative aspects you see with watching video in virtual reality (if any).

a) Do you think these would stop you from watching video in virtual reality?23. How do you imagine a user interface will look like in virtual reality?24. Have you ever controlled a system with your eye movements or head movements?

a) How was the experience?

Appendix B: Interview questions

Questions asked to the user after the usability test (translated to English - original in Swedish)

1. What kind of feelings did you experience during the use? a) Why do you think you were experiencing them?

2. How would you describe this experience compared to your expectations?3. If you compare watching video with a head-mounted display and how you normally watch video, which do you think give

the best experience? a) Why?

4. What (if anything) would you like to experience with this kind of technology?5. What do you think is the most interesting and valuable part of watching video in virtual reality?6. How did you feel about the way you were navigating in the application?7. Did you feel like you could control everything you wanted to control in the user interface?8. How did the time it took to make a selection feel like?9. Was there anything that you felt was hard to understand?10. Was there anything that you felt was easy to understand?11. Was there anything that surprised you?12. Was there any functionality you felt you were missing?13. Was there anything that annoyed you?14. What do you think would have made the experience better?15. What would have made you chose to watch video in virtual reality over watching it on any other type of screen?16. Was there anything that you liked in the user interface?

a) Why?17. Was there anything that you disliked in the user interface?

a) Why?18. If you could have changed the user interface so it would become easier to use, what would you have liked to do?19. If you could have changed the user interface so it would become more fun to use, what would you have liked to do?20. Of all the things we have discussed during this session, what do you think have been the most important?

Appendix C: Questions after usability test

Appendix D: Survey design

Heuristic evaluation result

Problem name Problem description Heuristic(s) Severity

GLOBAL:Selection of function occurs before user is finished reading and interpreting the function name and icon

The user looks at a menu option and starts reading the text explaining the option but the selection of the option is completed before the user has the opportunity to finish reading and understand the function he/she just selected/activated.

1. Visibility of system status 3. User control and freedom5. Error prevention 6. Recognition rather than recall

High

GLOBAL Hard to see selection result and where to continue interaction to reach goal

The user choose “movies” in the main menu but does not see any change in the VRGUI as a respons to the action and does not know where to continue looking for the movie s/he was looking for and reach the goal of starting it. The user gaze at the button for leak light in the setting menu but does not see or notice the result of the action because s/he is to focused on the button and the change is to far away from the focus point in the persons FOV.

1. Visibility of system status2. Match between system and the real world 6. Recognition rather than recall

High

GLOBAL No way to undo or go back from faulty or accidental selection

When the user has done something by accident (sometimes not even aware of the selection/activation) there is no easy way to undo or go back from that selection. If a selection of a TV show from the display menu is done by accident - the menu is replaced with episodes from that TV show and if the user want to go back to se the display of all the TV shows s/he needs to start over by moving to the main menu and select TV shows again. If the user accidentally selects “Exit VR Experience” it will immediately close down the application and the user need to remove the smartphone from the HMD to restart the application.

1. Visibility of system status 3. User control and freedom5. Error prevention

High

Time consuming and hard to find a specific episode of TV show in display menu

The user have to scroll horizontally by turning their heads to the left or right to search for the right episode. Text is to small to be read while scrolling and there is no clear difference in imagery between seasons or episodes so the user is forced to stop the scrolling, turn his or her head in to the middle to read and then continue to scroll and guess where to stop next time.

3. User control and freedom5. Error prevention 6. Recognition rather than recall 7. Flexibility and efficiency of use

High

Non-ergonomic interaction required to reach goal

The user need to scroll in the display menu by turning his or her head to the right or left. The turn is beyond the comfortable degrees making the experience uncomfortable and leaving the neck soar.

7. Flexibility and efficiency of use High

Play/pause button display wrong icon (bug)

When the video is running, the play/pause button is displaying the play icon, confusing the user of the action that is pause if the user dwell long enough on it.

4. Consistency and standards 5. Error prevention

High

Information required for decisions is not visible when user is interacting with menu

Example 1: When choosing a new movie or TV show episode to watch fromt he display menu it might be important to know what is currently running on the screen and then the user have to look up from the display menu and at the screen or to the right to find the video information.Example 2: When the user is fast forwarding or rewinding the user can not see the timeline for the video so it is not possible to tell how far forward or rewind the user have moved into the video.

1. Visibility of system status5. Error prevention6. Recognition rather than recall

Medium

Icons used for “Exit VR Experience” & “Rewind 10 seconds” look like one usually used for a “go back” or undo action

The icon used for “Exit VR Experience” and “Rewind 10 seconds” is according to the users previous experience related to actions to “go back” or undo an action.

2. Match between system and the real world5. Error prevention

Medium

The same icon is used for both “Exit VR Experience” & “Rewind 10”

The same icon is used for two different actions and before the user gaze over them there is no explanatory text separating them from each other more than their different placement in the VRGUI.

1. Visibility of system status4. Consistency and standards5. Error prevention

Medium

Feedback during selection (when hovering) is not consistent across different objects the user can interact with

When the user is gazing at most object, s/he will se a orange progress circle filling to track the progress of the selection. But this circle is not used for certain selection/activation tasks such as fast forward and rewind. User waits for the normal feedback and it takes longer to realise when s/he has triggered the desired action.

1. Visibility of system status4. Consistency and standards

Medium

Icons & explaining text for setting menus functions hard to understand

The icons used and the text explaining each function in the setting menu is hard to interpret and does not match with the users previous experience and knowledge.

2. Match between system and the real world Medium

Help function is missing Help function is missing. 10. Help and documentation Medium

GLOBAL Unclear what is possible to interact with and what is not

Icons (like the two orange in the middle of the setting menu and the play menu) is not possible to interact with even though they look like they could be. The same goes for the progress bar below the display menu.

2. Match between system and the real world Low

Information about state of video missing

Information about total length of video and how long it has currently played is missing.

1. Visibility of system status Low

Appendix E: Heuristic evaluation result