研究生英语高级教程-第8单元

TooMuchTooSoon[1]Inasocietythatpridesitselfonprovidingitschildrenwithgreatopportunitiestolearn,growanddevelopisitpossiblethatwemightbedoingmoreharmthangood?[2]OnmorethanoneoccasionIhavepausedtoreflectonthatveryquestiongivensomecurrenttrendsandideasaboutchildrenaslittlespongesoflearning.Irememberseeingarecentcurrentaffairsprogramwheretherewasmuchhypeaboutteachingtwo-year-oldstoreadandwasmystifiedattheparentswhogleefullyexpressedhowtheywerepavingthewayfortheirchild’sfuturebyhavingthemparticipateinthisprogram.[3]Interestingly,manyofthesechildrenwerealsointhethrongsofextracurricularoverloadandshuffledfromoneformoftuitiontoanotherastheirparentsespousedhowimportantitwastogivethemthebeststartinlife…remember,thesekidsweretwo!Addingtothistypeofhypearenewsstoriesandadvertisementstellingparentsofparticulartoysand“educational”activitiesthatwillbuildbetterbrainsandturntheirchildrenintolittlegeniuses.[4]Moreover,inordertoensurethatchildrenhaveskillsandknowledgeneededforthefuture,schoolsareincreasingacademicdemandsonchildrenatveryyoungages—eveninpre-schoolorearlier.Thetruthofthematter,however,isthatanyagendawhichforceslearninguponyoungchildrenmayactuallybedoingmoreharmthangood.[5]Oneofthemostfascinatingneurologicalfindingsinrecentyearsistherecognitionoftheimportantinfluenceofexperienceonbraindevelopmentandlearning.Insomesensethisseemsratherintuitiveandmostpeoplehavealwaysknownthatwelearnfromexperience.WhatistrulyamazingishowexperienceactuallyshapesthearchitectureofthebrainandthefactthatthisprocessstartslongbeforelittleJohnnytakespianolessonsorsomeacademictest.Infact,Johnny’sbrainistakingshapeaboutthreeweeksafterconception.[6]Inuterus,Johnnyhasactuallybegunhislifelonglearningjourneyviasensorystimulireceivedfromtheworldinsideandoutsideofthewomb.Uponbirth,Johnny’slearningreallybeginstotakeoffwiththegrowthofconnections(synapses)betweensome100billionneurons.[7]Theseconnectionsareinfluencedbyindividualexperienceandthemorerepetitiveanexperiencethegreatertheopportunityforconnectionstobecomepermanentlyhardwired.ItiswidelyrecognizedthatJohnnywillneeddevelopmentallyappropriateenvironmentalstimulitofacilitatehislearningandneurologicalfunctioning.Importantly,over-stimulationandactivitiesthatareintroducedtoJohnnytooearlycanactuallyhinderhislearning.Inotherwords,“appropriate”doesnotnecessarilymeanmoreandmuchofthisisdependentonthegrowthofafattymaterialcalledmyelin.[8]Asnotedabove,neuronsprovidetherawmaterialforlearningbybuildingconnectionsinthebrain.Throughoutlifeneuronsbecomedifferentiatedtoassumespecialisedrolesandformconnectionswithotherneuronsenablingthemtocommunicateandstoreinformation.Stimulatingexperiencesactivatecertainconnections,repetitionconsolidatestheseconnectionsandthebrainlearns.However,thereisalsoaneurologicaltimetablethatextendsfrombirthintotheseconddecadeoflife.Throughearlychildhoodandintoadolescencethistimetableissignificantlyinfluencedbymyelin.Thisimportantmaterialinsulatesanequallyimportantpartoftheneuronknownasthe“axon”.Currentresearchidentifiesthattheescalationofmyelinoccursinvariousstagesandthereisactuallya100%increaseinmyelinduringadolescence.Inotherwords,thebuild-upandacquisitionofmyelintowardsfullbrainmaturationismoremarathonthansprintandnomeasureofextratuitionorearlytraininginanyactivitywillinfluencethisdevelopmentaltimeline.[9]Youmaybewonderingwhymyelinissosignificant.Asaninsulator,myelinaidsinthetransmissionofinformationfromoneneurontoanotherandthemore“myelinated”axonsinthebrain,thegreateropportunityforneuralinformationtobepassedquickly.Theendresultofallofthisisthatcertainactivitiesmaybeeasiertolearnwhenregionsofthebrainaresufficientlymyelinatedorwhenourbrainsbecome“fatter”.Thegrowthofmyelin,otherwiseknownasmyelination,isveryimportantforchildrenduetothefactthatwhenwearebornwehaveveryfewmyelinatedaxons.Thisisonereasonwhyvisualacuityandmotorcoordinationaresolimitedatbirth.[10]Anotherimportantaspectofmyelinisthataswegrowolderdifferentregionsofthebrainmyelinateatdifferentages.Forexample,whentheregionofthebrainresponsibleforlanguageproductionmyelinates,childrenarethenabletodevelopspeechandgrammar.Thesetimesofmyelinationhavebecomereferredtobyneuroscientistsas“learningwindows”andamazingly,ahealthybrainknowswhichareasneedtobemyelinatedfirstandthatmyelinationcannothappenallatonce;again,ittakestimetobecomea“fathead”.Therefore,claimsofteachingtwo-year-oldchildrentoreadwouldbehighlydependentonachild’sneuraldevelopment.[11]Giventheimportanceofexperience,somemightsuggestthattheearlierchildrenareintroducedtocertainexperiencesorstimulationthegreaterthepropensityforlearningandearlysuccess.However,whileweknowthatinputfromtheenvironmenthelpsshapethebrain,wemustalsorememberthatbrainmaturationandoveralldevelopmentdonotfollowaniceneatagenda.Significantly,eachindividualchildisdifferentandsimplyimmersingachildinanendlessbombardmentofstimulimaydomoreharmthangood.[12]Thinkofpenmanshipasanexample.Thereisnodenyingtheimportanceofprovidingachildwithopportunitiestocolour,doodleandmimiclettermakingwithdevelopmentallyappropriatetoolslikelar