潜意识暗示提高人机交互能力

SubliminalCuesWhileTeaching:HCITechniqueforEnhancedLearningPierreChalfounandClaudeFrassonDepartementd'lnformatiqueetdeRechercheOp@rationnelle,UniversitedeMontreal,Office2194,Montreal,Quebec,H3T1J4,CanadaReceived2June2010;Accepted25September2010AcademicEditor:KennethRevettCopyright©2011PierreChalfounandClaudeFrasson.ThisisanopenaccessarticledistributedundertheCreativeCommonsAttributionLicense,whichpermitsunrestricteduse,distribution,andreproductioninanymedium,providedtheoriginalworkisproperlycited.AbstractThispaperpresentsresultsfromanempiricalstudyconductedwithasubliminalteachingtechniqueaimedatenhancinglearner'sperformanceinIntelligentSystemsthroughtheuseofphysiologicalsensors.Thistechniqueusescarefullydesignedsubliminalcues(positive)andmiscues(negative)andprojectsthemunderthelearner'sperceptualvisualthreshold.Apositivecue,calledanswercue,isahintaimingtoenhancethelearner'sinductivereasoningabilitiesandprojectedinawaytohelpthemfigureoutthesolutionfasterbutmoreimportantlybetter.Anegativecue,calledmiscue,isalsousedandaimsatobviouslyattheopposite(distractthelearnerorleadthemtothewrongconclusion).Thelatestobtainedresultsshowedthatonlysubliminalcues,notmiscues,couldsignificantlyincreaselearnerperformanceandintuitioninalogic-basedproblem-solvingtask.Nonintrusivephysiologicalsensors(EEGforrecordingbrainwaves,bloodvolumepressuretocomputeheartrateandskinresponsetorecordskinconductivity)wereusedtorecordaffectiveandcerebralresponsesthroughouttheexperiment.Thedescriptiveanalysis,combinedwiththephysiologicaldata,providescompellingevidenceforthepositiveimpactofanswercuesonreasoningandintuitivedecisionmakinginalogic-basedproblem-solvingparadigm.IntroductionTheuseoftechnologytobuildIntelligentUserInterfaces(IUI)hasrevolutionizedthewaycomputersinteractwithhumanbeings.ExamplesoftheseIUIscanbefoundinvirtuallyeveryaspectofourlives,suchasmobilemediasharing[1,2],intelligentvehicularassistance[3],andmentalspellingmachines[4].OnegrowingareaofresearchwithintheHCIcommunityrecentlyhasbeenfocusingtowardsthedesignofsmartinterfacesforlearning.Indeed,asmartinterfaceshouldbeable,inalearningcontext,todetecttheuser'semotionalandcognitivestatesinordertoadjustandadapttheteachingmaterialaccordingly.SuchadaptivesystemsrelyingonefficientIUIsareknownasintelligenttutoringsystemsandarecomprisedofmultiplegoal-specificmodulestoaidthelearner.Oneofthesemodules,calledthetutor,makesuseofcognitivepedagogicalstrategiesandaffectivestatestoproperlymodelhumancognitionaccordingtothelearner'sconstantneedsandevolution.ThetutortakesadvantageofrecentdevelopmentinIUItoefficientlycommunicatewiththelearner.Thismultidisciplinaryfieldofresearchtriestoaccomplishthisdauntinggoalofuser-modelingandadaptationbyimplementingthemostrecentevolutionsandadvancesinvariousresearchareassuchasartificialintelligence,neuroscience,andcognitivescience.Oneofthoserecentadvancesthispastdecadehasbeentheshiftinemphasisforcognitivesciencefromlearner'sperformancetolearner'sexperienceduringlearning.Indeed,affectivestates,motivation,andknowledgeconstructionhavebeenextensivelymeasuredandexplored [5-8]andhaveshownthatemotionsareanimportantcomponentinskillacquisitionandplayapivotalroleinlearning.Indeed,researchesinneurosciencesandcognitivepsychologyhaveshownthatemotionsarewidelyrelatedtodiversecognitiveprocesses,suchasattention,problemsolving,anddecision-making[9,10].Emotionsinfluenceourbehaviorandplayanimportantroleinourevery-daydecision-makingprocesses[11].Cognitiveactivityisalsofundamentallyrelatedtoemotions[12].Cognitiveprocesssuchasproblemsolvinganddecisionmakingnotonlydependbutaregreatlyintertwinedwiththeindividual'semotionalstate[13].Moreover,emotionsareessentialactorsforcreativethinking,inspiration,aswellasconcentrationandmotivation[10,14].ItthenbecomesvitalforanHCIsystemtodetectandrecognizetheseemotionalandcognitivestates,viaphysiologicalsensorsorotherwise,andrelaythemtothepertinentITSmodules.Hence,learningsystemswouldbeabletointelligentlyadapttheircommunicationandinteractionwithlearnersthroughadaptiveHCIsystems.Nevertheless,amajorcomponentoflearninganddecisionmakingwhensolvingproblemshasbeenmostlyneglectedinthisresearchfield:humanunconsciouscognition.Indeed,thecognitiveunconsciousasamajorplayeristheintegrationandinterpretationofcomplexmaterialwithregardstodecisionmakingandpossiblylearning.Tothatend,alargebodyofworkinneuroscienceandotherfieldshasputforthcompellingevidencethatlearningsimple-to-complexinformationcanbedonewithoutperceptionorcompleteawarenesstothetaskathand[15-18].Theideathatanyinformationprojectedtoofasttobeconsciouslyperceivedbyalearner(calledsubliminalprojection)hasbeenthefocusofmuchresearchinneuroscienceandcognitivepsychology.AvarietyofIUIshavebeendesignedforsuchapurpose,rangingfromsimpletwo-dimensionalinterfaces(2D)tocomplex3Dimmersiveones [19-23].Furthermore,therecordingoftheneuralelectricalactivity,calledEEGactivity,presentinthebrainduringtheoccurrenceofthesementalprocessesisalsoanactiveresearchareainHCI.Indeed,anIUIthatdetectsbrainactivitycanrecognizeandquantifytheuser'sengagementlevelinspecificactivities[24].However,intheHCIcommunity,EEGactivityismainlyusedtoconstructbraincomputerinterfacesmainlyaimedatcharacterspellingoritemrecognition [4,18,25-27].Unfortunately,veryscarceresearchintheHCIcommunityhasemployedaffect,subliminalprimingandEEGforeducationalpurposes.Indeed,theexistenceofperceptuallearningwithoutperceptionhasnotonlybeenproven,butalsoreplicatedinonestudywedidtwoyearsago[19].Inthisstudy,wepresentedanovelsubliminalprimingtechniquebuiltintoanadaptiveIUIaimedatboostingperformancebyenhancingthelearner'sdeductivereasoningcapabilities.Ourfindingsconcurwiththeliterature:subliminalstimuli,whichisstimuliprojectedbelowthethresholdofconsciousperception,canenhancelearningandincreasethedeductivereasoningoflearnersonlyifcarefullyandintelligentlyconstructedbeforebeingintegratedintoanIUI.However,thisinitialstudysufferedfromamajorlimitation:theexclusiveuseofpositivesubliminalpriming(cuesdesignedtohelplearning,nothinderorinterferewithit).Thus,wedidnotknowwhateffectmightnegativecues,ormiscues,haveonlearningandperformancewhenintegratedintoourIUIsystem.Inthepresentpaper,weintendtofollowuponourrecentstudybydesigninganevolvedversionofouradaptiveIUIwithournovelsubliminallearningtechniqueaimedatenhancingthelearner'sinductivelearningcapabilities.ThisnewIUIimplementedinourtutoringsystemwillmarrypositiveandnegativeprimesaswellasaffectivesensorsinthestringent2Denvironmentresemblingonlinetests.Affectivesensorswillserveasimportantindicatorofthelearner'semotionalandcerebralstatewhenfacedwiththedecisionofcorrectlyansweringaquestion.Whenfacingaquestion,learnerscaneither(a)guesstheansweror(b)correctlyinferthesolution(sincethisisanexamandthesolutionisnotpresentedtothem).WebelievethatIUIswouldbeabletodetectbothoutcomes((a)and(b))byrecordingandanalyzingemotionalandcerebraldata.Wealsobelieve,basedontheextensiveliteraturetothateffect,thatsubliminalprimingshouldinfluencebothoutcomes.WethusintendtoinvestigatetherelevanceofaugmentingourIUIwithcerebralsensorsandusingoursubliminalteachingtechniquebystatingtwoHCI-researchquestions.First,doesintegratingdifferentsubliminalcuingtypes(positive,control,andmiscue)intothisnewlydesignedIUIenhanceorhamperthelearner'sinductivereasoningcapabilitiesandperformance?Second,whatsignificantphysiologicalimpactscanthisnewlydesignedinterfacewithoursubliminalteachingtechniquehaveonlearner'sperformanceduringquestionansweringaswellasontheentirelearningprocess?Theorganizationofthispaperisasfollows:inthefirstsection,wepresentpreviousworkrelatedtovariousaspectsofourresearch.ThesecondsectionwilldiscusspriminginHCI,morespecificallyfromaneducationalstandpoint.Thethirdsectionwilllaythebasesofphysiologicalrecordingsandimportancetoeducationandlearningingeneral.Thefourthsectiondescribestheexperimentsetupanddepictsthevariousaspectsrelatedtosubliminalcuesandmiscues.Thefifthsectionpresentstheobtainedresultswhicharediscussedinsectionsixleadingtothelastsectionwhereweconcludeandpresentfuturework.RelatedWorkThepresentworkemployssubliminalpriming,affect,andEEGtoinvestigatethepossiblecontributionofprimingtoenhancelearningandmorespecificallyinductivereasoning.Tothebestofourknowledge,thereareonlytwosimilarpapersintheITS/AIED(Artificialintelligenceineducation)/HCIcommunitythatemploysubliminalprimingandEEGinaneducationalcontext[28,29].Thefirstisourownworkwherewepresentedcerebralevidence,namely,aP300component(seebackgroundonEEGandaffectivedatabelow),toconfirmthatbothcuesandmiscueswereinterpretedinthebrain,butwithslightlydifferentlevelsandamplitudes.Thesecond,however,greatlydiffersfromoursintwoways:(1)theprimingusedisofapersonalandnotofacognitivenature(self-wordswereprojectedonthescreeninsteadofcognitivecuesandmiscues)and(2)theauthors'mainobjectivewastouseprimingtoenhancelearner'sself-esteemfirstandforemost.Thus,anyobservedperformanceincreasecouldbeconsideredasaprobablesideeffectofthehigherlevelofself-esteemreported.Inthepresentwork,cuesandmiscueswereconstructedpreciselytoenhanceperformancebyaugmentingthelearner'sinductivereasoningabilities.However,wewillbrieflydescribeinthissectiontheworkdoneinotherrelatedfieldsthathavebeenthedrivingforcebehindtheinspirationsandmotivationsforthiswork.Anexistingdissociationbetweenperformanceandconsciousnesshasbeenknowntoneurologistsforover100yearswithadisordercalledblindsight.Patientsinthisconditionareunabletoindentifyanythingpresentedinonesideoftheirvisualfieldeventhoughtheireyes(retinas)areperfectlyhealthy.Nevertheless,Poppelshowedthatpatientswithblindsightcanunconsciouslyidentifyandprocesssimplevisualinformationpresentedtotheir“blind”side*30+.Furthermore,DeGerderdemonstratedthatblindsightpatientscanrecognizeandidentifycomplexvisualstimuli(emotionalfaces)whensuchstimuliispresentedsubliminally[31].Theseresults,andmanyothers,havebeenreproducedsuccessfullyonhealthypatientsandhavecontributedtoclarify,andmoreimportantly,tojustifytheanatomicalseparationthatexistsbetweenconsciousandunconsciouscognition[32].Unfortunately,noworkintheHCIcommunity,besidesours[19,33],hasattemptedtouseaffectiveandcerebraldatainordertoassesstheimpactofsubliminalcuesandmiscuesonthelearner'sperformance,deductiveandinductivereasoning,aswellasdecisionmakinginaproblem-solvingcontext.However,ahandfulofpapersinvariousfieldshaveclaimedtheuseofsubliminalprimingasasupportformemoryintheHCIcommunity.Oneoftheearlyworksregardingtheimplementationofsubliminalcuesfortask-supportedoperationwithinasoftwarewasthetexteditorprogramofWallace[23].Inthisexperiment,Wallaceetal.investigatedtheresponseofsubjectswhenrequiringhelpfromatexteditor.Theyfoundthatthefrequencyatwhichsubjectsdemandedhelpwasmuchlowerwhentherequiredinformationwaspresentedinsubliminalmatter.Anotherveryimportantfindingisthefactthatallpreviousstudiesdidnothavetheintendedresultsbecausetheprojectedstimulusdidnottakeintoaccountthespecificationsofthecomputersuchasscreenresolutionandrefreshrate.ThememoryglassesbyDeVauletal.[20]usedwearableglassesthatprojectssubliminalcuesasastrategyforjust-in-timememorysupport.Theobjectivewastoinvestigatetheeffectofvarioussubliminalcues(correctandmisleading)onretentioninaword-facelearningparadigmandcomparerecallperformance.AnotheruseofprimingformemorysupportcanbefoundinthethesisofShutte[34],wheretheauthorassessedtheeffectsofbriefsubliminalprimesonmemoryretentionduringaninterferencetask.Thethesisexaminedindetailmultipleparametersofsubliminalprojectionssuchasduration,relevance,andcontract.Althoughtheresultsoftheseprimingseemedveryencouraging,theauthorcautionsHCIdesignersthatmisusingsubliminalprimingthatcanleadtocriticaldisruptionsofongoingtasks.FurtherworkfromMitchelletal.[35]hashypothesizedthatrecognitionperformanceinastandarditem-basedforgettingparadigmmaybealteredbysubliminalcues.Theseauthorsbelievethatthesecuescanautomaticallyactivatedifferentmnemonicstrategies,thusenhancingmemoryretentionandrecall.Theresultshaveshownthatitem-basedwordsprimedwiththeword“remember”seemtobebetterretainedthan“forgot”byaveryslimdifference,however.Besidesseemingtoimpactmemory,subliminalprimingcanalsohaveanemotionalconsequenceonlearners.Veryrecentworkfrom[21]putforwardaninterestingeffectthatsubliminalprimingcanhaveontheself-attributionofauthorshipofevents.Subjectswereaskedtocompeteagainstacomputerinremovingnonwordssuchas“gewxs”fromacomputerscreeninthefastesttimepossible.Afteradeterminedamountoftime,thecomputerwouldremovetheword.Subliminalprimesofself-associatedwordslike“I”and“me”beforeanactionincreasedthepersonalfeelingthatitwastheparticipantthateliminatedthenon-wordandnotthecomputer,thusincreasingthefeelingofself-authorshipofevents.Furthermore,monitoringtheemotionalreactionsofthelearnerusingphysiologicalsensorsinalearningenvironmentusingIUIisquiteexploredaswell.Indeed,theempathiccompanionisagoodexamplewheremultiplephysiologicalsensors,namely,galvanicskinresponse,heartrate,andrespirationweretakeninrealtimetoanalyzeandadaptthetutortotheemotionalreactionsofthelearnerinavirtual3DITS[36].BosmaandAndre[37]havemergedtwotechniquesinordertoresolveambiguitiesindialogueacts.TheyusedaBayesiannetworkapproachtodetermineanemotionalstateandafinitestatemachinemethodtostudythemeaningofdialogueactsaccordingtophysiologicaldata.Furtherresearchhasanalyzedamoredetailedandrelevantemotionalsignificanceofphysiologicalsignals,eitherincomplexlearningorgaming[38-41].ThereisunfortunatelyveryscarceworktoourknowledgeintheHCIfieldwhereEEGandemotionaldataareusedtoenhanceoradaptlearningaccordingtouser'sdemandsbesidestwonotableexceptions:(1)Stevensetal.employedalight-weightEEGmonitoringsystemtoevaluatechangesincognitiveworkload,engagementanddistractionasstudentsacquireproblemsolvingskills[42],and(2)Chaouachietal.havestartedtoinvestigatetheimportantlinkthatmayexistbetweenaffectandmentalworkloadasmeasuredbyawell-knownEEGmentalengagementindex[24].ThecurrentpaperispresentedthroughanewlydesignedIUIaimedatenhancingthelearner'sinductivereasoning.ThenewIUIisinterplaybetweensubliminalpriming,EEG,andaffectivedata.Thus,aprimeronsubliminalpriminginHCIwillfirstbepresented,followedbyabackgroundsurveyofEEGandaffectivedata,sincethesesensorsplayanimportant,andactive,partinourstudy.SubliminalPriminginHCIAsmentionedbefore,thisresearchfocusesonsubliminalstimulitoenhancelearninginatutoringsystem.Beforegoingfurther,weneedtoclearlyestablishtheterminologythatwillbeusedinthispaper.Indeed,thesimplementionofthewordsubliminalcanleadtoconfusion.Wefirststatethatalearnerisconsciouslyperceivingastimulusiftheyarefullyawareandabletoidentifythegivenstimulus.Intheexampleofacomputerscreensaverwhereonewouldseeaflyingwhiteboxoverablackcomputerscreen,thefactofidentifyingthewhiteboxissufficienttostatethatthelearnerconsciouslyperceivesit.However,ifweprojectveryquickly,10msforexample,theletter“A”inTimesNewRoman10pointsinlightgrayinthebottomleftcornerofthescreen,thenwecanstatethattheyhaveconsciouslyperceivedtheboxbutnottheletter.Thisisduetotheneurologicalpropertiesofconsciousperception:theexistenceofathresholdforconsciousaccess[15].Itispreciselythisthresholdthatweacceptasbeingthelinebetweenconsciousandsubconsciousperception(thatsomecancallunconsciousaswell).Thetechniqueusedtoprojectagivenstimulusbelowthisthresholdofawarenessiscalledsubliminalprimingasopposedtoaliminalprimingwherethestimuluscanbeconsciouslyperceivedabovethethreshold.Moreover,asubliminalstimulusmust,therefore,bepresentedforaveryshorttimeandcanvaryinintensity,duration,frequency,andshape.Ithas,howeverbeenestablishedthatsubliminalstimulicanbiasbehaviorandevenyieldbetterresultsthannosubliminalstimuliunderspecificexperimentalconditions[21,43].Indeed,simplysendingsubliminalmessageswithoutcaringforcontextnordesiredgoalsandemotionscanprovetobeinefficientorsimplyuseless[17,34].Thecognitiveprocessthattakesplacewhenthestimulus(vocalorvisual)iseitherunattendedorsubliminallyprojectedisastagethatwecallsubliminalprocessing.Contrarytopopularbelief,high-levelsemanticprocessinghasbeenobservedduringthisstage[44].Oneinterestingexampleisanearlystudyby[45],wheresubjectsweregivenunattendedstimulusintheformofwordsandwerecapableofdiscriminatingbetweentheiralternativemeanings.Anotherfascinatingexperimentplacedforwardthelong-termeffectofsubliminalprimingonthevisualsystem[43].Inthisexperiment,subjectslearnedataskwithoutactuallyrealizingit.Participantswereaskedtofocustheirattentiononrandomlettersappearingonacomputerscreenwhileatthesametimeimperceptiblemovingdotsindifferentdirectionswereappearingjustoutsideoftheirvisualfield.Afteramonth'straining,theparticipantssubconsciouslylearnedtorterciodgennitzifeyandbetthedotsmovementseveniftheirattentionwasconcentratedonthelettersappearingintheirvisualfieldonthescreen.Furthermore,theimpactofsubliminalstimulionbehaviorhasbeenproventobereliableonlyifthestimulusisgoalrelevantandpeoplearemotivated(eitherintrinsicallyorotherwise)topursuethegoal[17,46].Indeed,afewstunningexamplesofsuchimpactonbehaviorispresentedbyKarremansetal.[47]wheretheyarguethatforsuchsubliminalprimestobeprocessed(sayverbal),theprimeshavetoconsistofoneortwoshortwordsandnotofwholesentences.Thenotionofgoal-relevanceaswellaspropercueconstructionisthuscrucialforthesuccessofthehopedeffect.Themostrelevantwork,however,regardingourresearchhasbeendonebyLoweryetal.whodemonstratedthatsubliminalprimescanincreaseperformanceonmidtermexamscomparedtoneutralprimesandthatsubliminalprimingmayhavelong-termeffectsonreal-worldbehavior[48].Thus,webelievepossible,withcarefullydesignedsubliminalstimuli,toenhancelearningwithoutconsciousperceptionbythelearner.Wealsobelievethatthisnewformoflearningcantriggerasetofpositiveemotionalconditionsinthelearner,suchasmotivationandengagement.Inturn,thesepositiveemotionscanenhancelearning,inductiveproblemsolving,andpossiblydecisionmaking.Tothatend,wedesignedourcuestobeprojectedatstrategicspatialpositionsonthescreenbyfollowingthedirectionsgiveninatheoreticaltaxonomythatdifferentiatesbetweenconscious,preconscious,andsubliminalprocessingproposedbyDehaneetal.[32].Thistaxonomyisbasedontheglobalneuralworkspacehypothesis[49]thatdistinguishesprimeaccessibilityinthebrainbasedonstimulusstrengthandtop-downattention.Furthermore,thistaxonomyhasbeenquiterecentlyempiricallyvalidatedbyVandenBussche[50].BackgroundonEEGandAffectiveDataThissectionwillpresentbackgroundinformationontheimportanceofmeasuringphysiologicaldatabothintermsofEEGinthebrainasaffectivedataintermsofvalenceandarousal,twoimportantemotionaldimensionsusedinthisresearch.BackgroundonEEGIthasbeenknown,asearlyas1929,thattheon-goingelectricalfiringactivityofgroupsofneuronscanbemonitoredwithprobes,referredtoaselectrodes,placedonthescalp,outsidethebrain[51].Therecordingofsuchsmallactivity(inmicrovolts,10一6volts)iscalledelectroencephalographyorEEGandistypicallydonewithapolygraphdisplayingthecontinuouschangesinvoltageovertime.ThereareroughlytwomainparadigmswhenworkingwithEEGrawdata(seeFigure1).fig1Figure1:Snapshotofa10secondsEEGrawdataanalyzedusingtwomainparadigms.Thefirstparadigm,time/frequencyanalysis(typicallyusingafastFourriertransformationorFFT),isanoveralllookatspecificfrequenciesoveraperiodoftime.Thistechniqueismainlyusedtoclinicallyhelpdiagnosemultipledisorderssuchasepilepsy,sleepdisturbances,andattentiondisordersbyemployingneurofeedbackprotocols[52].Thistypeofanalysisgivesrelativelyfairinformationabouttheoverallmentalstateofanindividualbasedonbrainlocationsbeingsurveyed.Forexample,Alphawaves,orbands,are8to12HzrelativelylargeamplitudeEEGwavesthatareusuallyassociatedwitharelaxedbutawakestate[52].However,Alphaasymmetrypatternsbetweenlefthemisphere(LH)andrighthemisphere(RH)recordingswhileadultsubjectsareclosingtheireyes(calledeyesclosed)arecommonpatternsindepression(C3LHAlpha>C4RHAlpha).Thus,specificmentalchangescanbeassessedbycomparingrecordingsfrommultiplescalpsitesusinga3DspectrogramsuchastheonedepictedinFigure1.Althoughnoconsensusispresentlyavailableregardingbanddistribution,thefollowingrangesarethemostcommonlyagreeduponbytherapists:Delta(1一4Hz),Theta(4-8Hz),Alpha(8-12Hz),Beta(12-32Hz),andGamma(38-42Hz)[52].Indeed,inaneducationalsetting,attentionandsemanticmemoryperformancecanbothbeascertainedfromvariationofAlphaandThetabands[52,53].ChangesintheAlphabandhasalsobeenknowntocorrelatetoarithmeticstrategyusedinadditionandsubtractionwhichisveryclosetowhatwearetryingtoimproveinourstudy[54].Regardingdecisionmaking,Alpha,Beta,andDeltahavebeenshowntobevaluablemarkersforthebalancebetweenrewardandpunishment[55].Indeed,slowDeltaandThetawaveshavebeenlinkedtosubcorticalbrainregionsinvolvedinaffectiveprocesses[56,57]whereasfastBetaactivityhasbeenassociatedwithcognitivecontrolprocesses[58].Also,specificbands,suchastheGammaand40Hzbands,havebeenquiteextensivelystudieswhenitcomestoinsightfulproblemsolving[59,60].Anotherexplorationmadeinthe1980swastheexplorationofasymmetriesbetweenbrainregionsregardingspecificcognitivefunctions[61,62].Thesefindingsyieldedsomeinterestingmetrics,calledratios,tomeasureandexpressmentaloperations.Thus,recentworkinasymmetryanalysisrelevanttoourresearchhasrevealedhigherBetaasymmetriesfromtheleftbrainduringcomplexarithmeticprocessescomparedtosimplecomputations[63].Thisareaofresearchcanpotentiallybequiteinvaluableinaccessingwhetherthelearnerisengagedinfartoomuchmentalarithmeticthanrequiredforaspecificlesson.Thesecondparadigm,however,calledERPwaveformanalysis,takesadvantageofneurologicalpropertiesoftherawEEGsignaltogainbetterinsightintothecognitiveprocessingmechanismsinthebrain.Itdoessobysynchronizing(alsocalledlocking)therecordingoftherawEEGtoanevent.Byeventwemeananactionsuchasviewingapicturefromtheinternetordisplayingemotionalversusnonemotionalwordsonacomputerscreen(e.g.,love,murderversuschair,andtable).TheresultingEEGactivityiscalledan“Event-RelatedPotential”(ERP)whichcanbeeasilydistinguishedfromtherawEEG(toppartofFigure1)byitsconsistentmorphologicalshape(e.g.,theP300boldlineofFigure1appearingapproximately300msfollowinganevent).WhiletherawEEGismadeupofallbrainactivityataparticularpointintime,specificallyleftandrighthemisphereinthisexample,theERPisonlypartofthatrawactivityassociatedwiththeprocessingofaspecificevent.ERPsaredefinedbytheiramplitudeandlatency(thetimetakentoattainpeakamplitude).TovisualizeERPs,onemustusesignalprocessingtechniquestoeliminatenoneventactivitybyusingspecificband-passfiltersandaveragingmultipleepochstogether[64].Theaveragingprocesstendstodecreasetheinfluenceofrandomactivity(e.g.,thegraydottedlinesinFigure1)whilemaintainingtheconsistentevent-relatedactivity(e.g.,thesolidlineinFigure1).ByconventionERPresearchersseparateERPwaveformsintoseveralbasicpartscalledcomponents[64].Cognitivescientistshavebeenmostinterestedinthelong-latencyERPcomponentswhichincludetheN400andP300components.ThelettersPandNrepresentthepolarityofthecomponent,andthenumbersrepresenttheirlatencyafterstimulusonset(e.g.,theP300isapositivecomponentpeakingat300ms).Ingeneral,componentsoccurringafter250milliseconds,namely,theP300component,arethoughttoreflecthigher-ordercognitiveprocesses(e.g.,selectiveattention,resourceallocation,andlanguage)[25,64].Inthelightofwhathasjustbeenpresented,itisimportantto