BehavioralPPT课件

BehavioralTheoriesofLearning,.,2,Behaviorallearningtheoriesvs.focusonthewaysinwhichpleasurableorunpleasantconsequencesofbehaviorchangeindividualsbehaviorovertimeandwaysinwhichindividualsmodeltheirbehavioronthatofothers.,Aims:todefinelearningandthentopresentbehavioralandsociallearningtheories,explanationsforlearningthatemphasizeobservablebehaviors.,cognitivelearningtheoriesemphasizeunobservablementalprocessesthatpeopleusetolearnandremembernewinformationorskills.,.,3,WhatisLearning?Learningisusuallydefinedasachangeinanindividualcausedbyexperience(seeMazur,1990).Changescausedbydevelop-ment(suchasgrowingtaller)arenotinstancesoflearning.Neitherarecharacteristicsofindividualsthatarepresentatbirth(suchasreflexesandresponsestohungerorpain).However,humansdosomuchlearningfromthedayoftheirbirth(andsomesayearlier)entional,aswhenstudentsacquireinformationpresentedinaclassroomorwhentheylooksome-TwowaysthingupontheInternet.unintentional,asinthecaseofthechildsreactiontotheneedle.Allsortsoflearningaregoingonallthetime.,.,4,WhatBehavioralLearningTheoriesHaveEvolved?Pavlov:ClassicalConditioningThorndike:TheLawofEffectSkinner:OperantConditioning,.,5,Pavlov:ClassicalConditioningExperiment:Inthelate1800sandearly1900s,Pavlovandhiscolleaguesstudiedthedigestiveprocessindogs.Duringtheresearch,thescientistsnoticedchangesinthetimingandrateofsalivationoftheseanimals.Pavlovobservedthatifmeatpowderwasplacedinornearthemouthofahungrydog,thedogwouldsalivate.Becausethemeatpowderprovokedthisresponseautomati-cally,withoutanypriortrainingorconditioning,themeatpow-derisreferredtoasanunconditionedstimulus.Similarly,becausesalivationoccurredautomaticallyinthepresenceofmeat,alsowithouttheneedforanytrainingorexperience,thisresponseofsalivatingisreferredtoasanunconditionedresponse.,.,6,Pavlov:ClassicalConditioningWhereasthemeatwillproducesalivationwithoutanypreviousexperienceortraining,otherstimuli,suchasabell,willnotproducesalivation.Becausethesestimulihavenoeffectontheresponseinquestion,theyarereferredtoasneutralstimuli.Pavlovsexperimentsshowedthatifapreviouslyneutralstimul-usispairedwithanunconditionedstimulus,theneutralstimu-lusbecomesaconditionedstimulusandgainsthepowertopromptaresponsesimilartothatproducedbytheunconditio-nedstimulus.Afterthebellandthemeatarepresentedtogether,theringingofthebellalonecausesthedogtosalivate.Thisprocessisrefe-rredtoasclassicalconditioning.,.,7,Pavlov:ClassicalConditioningPavlovsemphasisonobservationandcarefulmeasurementandhissystematicexplorationofseveralaspectsoflearninghelpedtoadvancethescientificstudyoflearning.Pavlovalsoleftotherbehavioraltheoristswithsignificantmysteries,suchastheprocessbywhichneutralstimulitakeonmeaning.Althoughhisfindingshavefewapplicationstoclassroominstruction,theycanhelpateacherunderstandmanysituations,suchaswhenachildsanxietyaboutbeingamongstrangersgraduallydevelopsintoadebilitatingfearofcomingtoschool.,.,8,Thorndike:TheLawofEffectExperiment:ThorndikewentbeyondParlorbyshowingthatstimulithatoccurredafterabehaviorhadaninfluenceonfuturebehaviors.Inmanyofhisexperiments,Thorndikeplacedcatsinboxesfromwhichtheyhadtoescapetogetfood.Heobservedthatovertime,thecatsleaenedhowtogetoutoftheboxmoreandmorequicklybyrepeatingthebehaviorsthatledtoescapeandnotrepeatingthebehaviorsthatwereineffective.Fromtheseexperiments,ThorndikedevelopedhisLawofEffect.ThorndikesLawofEffectstatesthatifanactisfollowedbyasatisfy-ingchangeintheenvironment,thelikelihoodthattheactwillbere-peatedinsimilarsituationsincreases.However,ifabehaviorisfollowedbyanunsatisfyingchangeintheenvironment,thechancesthatthebehaviorwillberepeateddecrease.Thus,Thorndikeshowedthattheconsequencesofonespresentbehaviorplayacrucialroleindeterminingonesfuturebehavior.,.,9,Skinner:OperantConditioningExperiment:B.F.Skinnerproposedthatreflexivebehavioraccountsforonlyasmallproportionofallactions.Skinnerproposedanotherclassofbehavior,whichhelabeledoperantbehaviorsbecausetheyoperateontheenvironmentintheapparentabsenceofanyunconditionedstimuli,suchasfood.LikeThorndikes,Skinnersworkfocusedontherelationbetweenbehavioranditsconsequences.Forexample,ifanindividualsbehaviorisimmediatelyfollowedbypleasurableconsequences,theindividualengageinthatbehaviormorefrequently.Theuseofpleasantandunpleasantconsequencestochangebehaviorisoftenreferredtoasoperantconditioning.Skinnersworkfocusedonplacingsubjectsincontrolledsituationsand0bservingthechangesintheirbehaviorproducedbysystematicchangesintheconsequencesoftheirbehavior(seeIversen,1992).Skinnerisfamousforhisdevelopmentanduseofadevicethatis,.,10,Skinner:OperantConditioningcommonlyreferredtoastheSkinnerbox.Skinnerboxescontainaverysimpleapparatusforstudyingthebehaviorofanimals,usuallyratsandpigeons.ASkinnerboxforratswouldconsistofabarthatiseasyfortherattopress,afooddispenserthatcouldgivetheratanelletoffood,andawaterdispense.Theratcouldnotseeorhearanythingoutsideofthebox,soallstimuliwouldbecontrolledbytheexperimenter.OneimportantadvantageoftheSkinnerboxisthatitallowsforcarefulscientificstudyofbehaviorinacontrolledenvironment(Delpratounpleasantconsequencesweakenit.Inotherwords,pleasurableconsequencesincreasethefrequencywithwhichanindividualengagesinabehavior,whereasunpleasantconsequencesreducethefrequencyofabehavior.Ifstudentsenjoyreadingbooks,theywillprobablyreadmoreoften.Iftheyfindstoriesboringorareunabletoconcentrate,theymayreadlessoften,choosingotheractivitiesinstead.Pleasurableconsequencesarecalledreinforcers;unpleasantconsequencesarecalledpunishers.,.,13,ReinforcersAreinforcerisdefinedasanyconsequencethatstrengthens(thatis,increasesthefrequencyof)abehavior.Notethattheeffectivenessofthereinforcermustbedemonstrated.Wecannotassumethataparticularconsequenceisareinforceruntilwehaveevidencethatitstrengthensbehaviorforaparticularindividual.Forexample,candymightgenerallybeconsideredareinforcerforyoungchildren,butafterabigmealachildmightnotfindcandypleasurable,andsomechildrendonotlikecandyatall.Ateacherwhosays,Ireinforcedhimwithpraiseforstayinginhisseatduringmathtime,butitdidntwork,maybemisusingthetermreinforcedifthereisnoevidencethatpraiseisinfactareinforcerforthisparticularstudent.Norewardcanbeassumedtobeareinforcerforeveryoneunderallconditions.,.,14,ReinforcersTwobroadcategories:Primaryreinforcerssatisfybasichumanneeds.Someexamplesarefood,water,security,warmth,andsex.Secondaryreinforcersarereinforcersthatacquiretheirvaluebybeingassociatedwithprimaryreinforcersorotherwell-establishedsecondaryreinforcers.Forexample,moneyandgradesareexamplesofsecondaryreinforcersbecausetheyhavenovalueinthemselvesbuthavebeenassociatedwithprimaryreinforcersorwithotherwell-establishedsecondaryreinforcers.threebasiccategoriesofsecondaryreinforcer:socialreinforcers:eg.praise,smiles,hugs,orattention.activityreinforcers:eg.accesstotoys,games,orfunactivities.token(orsymbolic)reinforcers:eg.money,grades,stars,orpointsthatindividualscanexchangeforotherreinforcers.,.,15,PositiveReinforcersPleasurableconsequencegiventostrengthenbehavior.Suchaspraise,grades,andstars.,Reinforcers,NegativeReinforcersReleasefromanunpleasantsituation,giventostrengthenbehavior.Forexample,aparentmightreleaseastudentfromdoingthedishesifthestudentcompleteshisorherhomework.Ifdoingthedishesisseenasanunpleasanttask,releasefromitwillbereinforcing.,.,16,ReinforcersPremackPrinciple:Rulestatingthatenjoyableactivitiescanbeusedtoreinforceparticipationinlessenjoyableactivities.Oneimportantprincipleofbehavioristhatwecanpromoteless-desired(low-strength)activitiesbylinkingthemtomore-desiredactivities.Forexample,ateachermightsay,Assoonasyoufinishyourwork,youmaygooutsideorCleanupyourartproject,andthenIwillreadyouastory.ThePremackPrincipleissometimescalledGrandmasRulefromtheage-oldstatementEatyourvegetables,andthenyoumayplay.TeacherscanusethePremackPrinciplebyalternatingmoreenjoyableactivitieswithlessenjoyableonesandmakingparticipationintheenjoyableactivitiesdependonsuccessfulcompletionofthelessenjo-yableones.,.,17,ClassroomUsesofReinforcementThemainguidelinesfortheuseofreinforcementtoincreasedesiredbe.haviorintheclassroomareasfollows(seeBaldwinWielkiewicz,1995):1.Decidewhatbehaviorsyouwantfromstudents,andreinforcethesebehaviorswhentheyoccur.Forexample,praiseorrewardgoodwork.Donotpraiseorrewardworkthatisnotuptostudentscapabilities.Asstudentsbeginanewtask,theywillneedtobereinforcedateverystepalongtheway.Closeapproximationsofwhatyouhopetoaccomplishasafinalproductmustreceivepositivefeedback.Breakdownnewbehaviors(classroomassignments)intosmallerpartsandprovideadequaterewardsalongtheway.,.,18,2.Tellstudentswhatbehaviorsyouwant;whentheyexhibitthedesiredbehaviorsandyoureinforcethem,tellthemwhy.Presentstudentswitharubricthatitemizesthecriteriayouwillusewhenevaluatingtheirworkandincludethepointvalueforeachcriterion.Studentsthenwillbeabletodiscriminatetheirownstrengthsandweaknessefromthefeedbacktheyreceivefromyou.3.Reinforceappropriatebehaviorassoonaspossibleafteritoccurs.Delayedreinforcementislesseffectivethanimmediatereinforcement.Whenyouaregradinganassignment,presentfeedbacktothestudentsassoonaspossible.Itisimportantthatstudentsknowhowtheyaredoinginclass,sodontdelaywiththeirgrades.Whenconstrucunganassignment,youshouldalwaysconsiderthegradingschemethatyouwilluseandhowlongitwilltakeyoutoprovidetheintendedfeedback.,.,19,ReinforcersIntrinsicreinforcers:Behaviorsthatapersonenjoysengaginginfortheirownsake,withoutanyreward.Peopleliketodraw,read,sing,playgames,hike,orswimfornoreasonotherthanthefunofdoingit.Reinforcers0fthistypearecalledintrinsicreinforcers,andpeoplecanbedescribedasbeingintrinsical-lymotivatedtoengageinagivenactivity.Extrinsicreinforcers:Praiseorrewardsgiventomotivatepeopletoengageinbehaviorthattheymightnotengageinwithoutthem.Verbalpraiseandothertypesoffeedbackareextrinsicreinforcersthathavebeenfoundtoincrease,notdecrease,intrinsicinterest.Teachersshouldbecautiousaboutgivingtangiblereinforcerstochildrenforactivitiestheywouldhavedoneontheirown.,.,20,PracticalReinforcersAnythingthatchildrenlikecanbeaneffectivereinforcer,butthereareobviouspracticallimitationsonwhatshouldbeusedinclassrooms.Onegeneralprincipleofpositivereinforcementisthatitisbesttousetheleastelaborateortangiblereinforcerthatwillwork.Inotherwords,ifpraiseorself-reinforcementwillwork,dontusecertificates.Ifcertificateswillwork,dontusesmalltoys.Ifsmalltoyswillwork,dontusefood.However,donothesitatetousewhateverpracticalreinforcerisnecessarytomotivatechildrentodoimportantthings.Inparticular,tryallpossiblereinforcementstrategiesbeforeeventhink-ingofpunishment.Afewcategoriesofreinforcersandexamplesofeachappearhere(alsoseeAlbertoWielkiewicz,1995).Thesearearrangedfromleasttangibletomosttangible.,.,21,PracticalReinforcersSelf-reinforeement.Studentsmaybetaughttopraisethemselves,givethemselvesamentalpatontheback,checkoffprogressonaform,givethemselvesashortbreak,orotherwisereinforcethemselvesforcompletingataskorstayingoutoftrouble.Praise.PhrasessuchasGoodjob,Waytogo,Iknewyoucoulddoit,andotherverbalpraisecanbeeffective,butthesamemessagecanoftenbedeliveredwithasmile,awink,athumbs-upsignal,orapatontheback.Incooperativelearningandpeertutoring,studentscanbeencouragedtopraiseeachotherforappropriatebehavior.Attention.Theattentionofavaluedadultorpeercanbeaveryeffectivereinforcerformanychildren.Listening,nodding,ormovingclosermayprovideachildwiththepositiveattentionsheorheisseeking.Forout-standingperformanceorformeetinggoalsoveralongertimeperiod,studentsmightbeallowedaspecialtimetovisitwiththecustodian,helpintheoffice,ortakeawalkwiththeprincipal.,.,22,PracticalReinforcersGradesandrecognition.Gradesandrecognition(e.g.,certificatesofaccomplishment)canbeeffectivebothingivingstudentspositivefeedbackontheireffortsandincommunicatingprogresstoparents,whoarelikelytoreinforcegoodreportsthemselves.Publicdisplaysofgoodwork,notesfromtheprincipal,andotherhonorscanhavethesameeffect.Quizscores,behaviorratings,andotherfeedbackgivenfrequentlycanbemoreeffectivethanreportcardgradesgivenformonthsofwork.Home-basedreinforcement.Parentscanbeexplicitlyincludedinareinforcementsystem.Teacherscanworkoutwithparentsanarrangementinwhichparentsgivetheirchildrenspecialprivilegesathomeifthechildrenmeetwell-specifiedstandardsofbehaviororperformance.Privileges.Childrencanearnfreetime,accesstospecialequipment(e.g.,soccerballs),orspecialroles(suchasrunningerrandsordistributingpapers).Childrenorgroupswhobehavedwellcansimplybeallowed,.,23,PracticalReinforcerstolineupfirstforrecessordismissalortohaveothersmallprivileges.Activityreinforcers.Onthebasisofachievingpreestablishedstandards,studentscanearnfreetime,videos,games,oraccesstootherfunactivities.Activityreinforcerslendthemselvesparticularlywelltogroupcontingencies,inwhichawholeclasscanearnfreetimeorspecialactivitiesifthewholeclassachievesastandard.Tangiblereinforcers.Childrenmayearnpointsforachievementorgoodbehaviorthatheycanexchangeforsmalltoys,erasers,pencils,marb-les,comicbooks,stickers,andsoon.Tangiblereinforcersusuallyworkbetterifchildrenhaveachoiceamongseveraloptions(Fishertimeoutdeprivesthemiscreantofthisreinforcer.Theuseoftimeoutasaconsequenceformisbehaviorhasgenerallybeenfoundtoreducethemisbehavior(Costenbader&Reading-Brown,1995).,.,26,ImmediacyofConsequencesOneveryimportantprincipleofbehaviorallearningtheoriesisthatconsequencesthatfollowbehaviorscloselyintimeaffectbehaviorfarmorethandelayedconsequencesdo.Asmallerreinforcerthatisgivenimmediatelygenerallyhasamuchlargereffectthandoesalargereinforcerthatisgivenlater(Kulik&Kulik,1988).Immediatefeedbackservesatleasttwopurposes:First,itmakescleartheconnectionbetweenbehaviorandconsequence.Second,itincreasestheinformationalvalueofthefeedback.Inpractice,fewclassroomteacherscanprovideindividualfeedbackimmediatelytoalltheirstudents.However,thesameresultscanbeobtainedbygivingstudentsanswersrightaftertheycompletetheirwork.Indealingwithmisbehavior,teacherscanapplytheprincipleofimmediacyofconsequencesbyrespondingimmediatelyandpositive-lywhenstudentsarenotmisbehaving-ineffect,bycatchingthemintheactofbeinggood!,.,27,ShapingWhenteachersguidestudentstowardgoalsbyreinforcingthemanystepsthatleadtosuccess,theyareusingatechniquecalledshaping.Thetermshapingisusedinbehaviorallearningtheoriestorefertotheteachingofnewskillsorbehaviorsbyreinforcinglearnersforapproachingthedesiredfinalbehavior(J.E.Walker&Shea,1999).Shapingisanimportanttoolinclassroominstruction.theteachermightteachtheskillsstepbystep,graduallyshapingthefinalskill.Ateachstage,studentswouldhaveagoodchancetobereinforced,becausethecriterionforreinforcementwouldbewithintheirgrasp.Theprinciplehereisthatstudentsshouldbereinforcedforbehaviorsthatarewithintheircurrentcapabilitiesbutthatalsostretchthemtowardnewskills.,.,28,ExtinctionTheprocessofweakeningandeventualeliminationofalearnedbehaviorasreinforcementwithdrawniscalledextinction.Behaviorintensifieswhenthereinforcerisfirstwithdrawn,thenrapidlyweakensuntilthebehaviordisappears.Still,thebehaviormayreturnaftermuchtimehaspassed.Thecharacteristicextinctionburst,theincreaseinlevelsofabehaviorintheearlystagesofextinction,hasimportantconsequencesforclassroommanagement.Extinctionofapreviouslylearnedbehaviorcanbehastenedwhensomestimulusorcueinformstheindividualthatbehaviorsthatwereoncereinforcedwillnolongerbereinforced.,.,29,SchedulesofReinforcementSchedulesofReinforcementreferstothefrequencywithwhichreinfor-cersaregiven,theamountoftimethatelapsesbetweenopportunitiesforreinforcement,andthepredictabilityofreinforcement.Onecommonscheduleofreinforcementisthefixed-ratio(FR)schedule,inwhichareinforcerisgivenafterafixednumberofbehaviors.Fixed-ratioschedulesareeffectiveinmotivatingindividualstodoagreatdealofwork-especiallyifthefixedratiostartswithcontinuousreinforcementtogettheindividualgoingandthenmovestohighrequirementsforreinforcement.Onereasonthathighrequirementsforreinforcementproducehigherlevelsofbehaviorthanlowrequirementsisthatreinforcingtoofrequentlycanmakethevalueofthereinforcerwearoff.Studentswhowerepraisedforeverymathproblemwouldsoongrowfiredofbeingpraised,andthereinforcermightloseitsvalue.,.,30,SchedulesofReinforcementAvariable-ratio(VR)scheduleofreinforcementisoneinwhichthenumberofbehaviorsrequiredforreinforcementisunpredictable,althoughitiscertainthatthebehaviorswilleventuallybereinforced.Variable-ratioschdulesarehighlyresistanttoextinction.Evenafterbehaviorsarenolongerbeingreinforced,peoplemaynotgivenupworkingforalongtime.Becausetheyhavelearnedthatitmaytakealotofworktoberewarded,theykeeponworkinginthemistakenbeliefthatthenexteffortmightjustpayoff.Infixed-intervalschedules,reinforcementisavailableonlyatcertainperiodictimes.Fixed-intervalschedulescreateaninterestingpatternofbehavior.Theindividualmaydoverylittleuntiljustbeforereinforcementisavailab-le,thenputforthaburstofeffortasthetimeforreinforcementapproa-ches.Thesecharacteristicsoffixed-intervalschedulessuggestthatfrequentshortquizzesmaybebetterthaninfrequentmajorexams,.,31,SchedulesofReinforcementforencouragingstudentstogivetheirbesteffortallthetimeratherthanputtinginall-nightersbeforetheexam(Crooks,1988).Inavariable-intervalschedule,reinforcementisavailableatsometimesbutnotatothers,andwehavenoideawhenabehaviorwillbereinforced.Variable-intervalschedulesareveryeffectiveformaintainingahighrateofbehaviorandarehighlyresistanttoextinction.,.,32,MaintenanceMaintenanceisdefinedasthecontinuationofbehavior.Themaintenanceofbehavioralsooccurswithbehaviorsthatdonotneedtobereinforcedbecausetheyareintrinsicallyreinforcing,whichistosaythatengaginginthesebehaviorsispleasurableinitself.Forexample,manychildrenlovetodraw,tofigureoutproblems,ortolearnaboutthingseveniftheyareneverreinforcedfordoingso.Theconceptofresistancetoextinction,discussedearlier(inthesectiononschedulesofreinforcement),iscentraltoanunderstandingofmaintenanceoflearnedbehavior.Aswasnoted,whennewbehaviorsarebeingintroduced,reinforcementforcorrectresponsesshouldbefrequentandpredictable.However,oncethebehaviorsareestablished,reinforcementforcorrectresponsesshouldbecomelessfrequentandlesspredictable.Thereasonforthisisthatvariableschedulesofreinforcementan