10-The-Poverty-of-the-Stimulus-Argument

110ThePovertyoftheStimulusArgument2GeneraldataExceptforcongenitaldefectortraumaweallendupusing(atleast)aparticularlanguage,althoughwemighthaveendedupusinganyotherlanguage.Ourbrains,unlikethoseofotherspecies,aresuchastoenableustoacquirelanguageassuch,althoughtheyarenotprimedtoacquireanyparticularlanguage.3Theacquisitionoflanguageisspeciesspecific.Whateverdistinguishesusfromotheranimalsmustbespecificenough(notnecessarilyspecifictolanguage)forustoarriveatEnglishorItalianorNavajo,etc.Itmustalsobegeneralenoughtotargetanylanguagewithequalease.4InnatenessHumanspossessinnateequipment,whetherspecifictolanguageornot,thatenablesthemtoacquireanylanguage.Sofar,then,wedon’thaveanyargumentfortheclaimthatthehumanchildbeginswithsomethingspecificallylinguistic.Someother,speciesspecific,capacitycoulddothejob.5Thelanguageswespeakareverydifferent.Theremightbeuniversalfeaturessharedbyalllanguages,buttheyarenotapparentintheseeminglyinfinitevarietyofdatatowhichchildrenareexposed.Whatelsedoesthechildhaveotherthanthedata?Itseemsthatweareinfinitelyfarfromtheexplanatoryidealsituation,i.e.,themorelanguagesthereare,themoreinclusivemustbeourinitialcapacitytorepresentlanguage.6Triviality.Thatthechildbeginswithinnateequipmentistrueenough,butweseemtorequiresomethingdecidedlylesstrivial.Whatthechild’sinnateequipmentisrequiredtoactivelyconstrainsits‘choices’astowhatispartofthelanguagetobeattained.Butnochildiswiredtotargetanyparticularlanguage:thechildcanmaketheright‘choices’aboutanylanguagewithequalease.7InitialstageThechildrenmustbeginwith‘knowledge’specifictolanguage,i.e.,thedatatowhichthechildisexposedis‘understood’intermsofpriorlinguisticconceptsasopposedtogeneralconceptsofpatternorfrequency,say.E.g.:childrendistinguishphonemesfromrumours.8PovertyofthestimulusAchildmayacquirealanguageeventhoughthedataitselfistoopoortodeterminethelanguage:thechildneedsnoevidenceformuchoftheknowledgeshebringstothelearningsituation.Childrenacquirelanguagefrompidgin.Roughly,childrenalwaysmaketheright‘hypotheses’asafunctionoftheirgeneticendowment.9Sincethechildcanfixateonanylanguageinthefaceofapovertyofstimulusabouteachlanguageandsincealllanguagesareequallyacquirable,childrenallbeginwiththesameuniversallinguisticknowledge.Thisistheessenceofthepovertyofstimulusargument.10Thepovertyofthestimulusargumentdoesnottellus:1.Whatinformationisinnate.2.Howtheinnateinformationisrepresentedinthemind/brain.3.Whethertheinformationisavailabletoagenerallearningmechanismorspecifictoadedicatedone(i.e.generalintelligenceorlanguagemodule).Theseissuesaretobedecidedbythenormalscientificrouteofthetestingandcomparisonofhypotheses.11Positivedatatellsthechildthatsomeconstructionisacceptable.Negativedatatellsthechildthatsomeconstructionisunacceptable.Thereismuchdiscussionofthisdifference,forithasbeenclaimedthatnegativeevidenceistypicallyunavailableandnotusedbythechildevenwhereitisavailable.12Childrenareinnatelyconstrainedtoinitially‘chose’thesmallestpossiblelanguagecompatiblewiththeirpositivedata.13MuchofthedebatearoundthePovertyoftheStimulusArgumentfocusesonnegativeevidence.Ifthereislotofnegativeevidencetherearemorechancesthatthechild’slearningisbasedontrialanderror.Evenifthereisplentyofnegativedata(whichisquestionable),thePovertyoftheStimulusArgumentisnotrefuted.14TherelativeneutralityofthePovertyoftheStimulusArgumentsuggestssomethingsurprising:thefactthatthechildcanacquireanylanguagewithoutseeminglyenoughdatatodoso,indicates,counter-intuitively,thatlanguagesarenotsodifferent.Theinnate‘hypotheses’thechildrenemploymustbeuniversal,ratherthanlanguageparticular.Imaginethateachlanguageisradicallydistinct,aneffectofamyriadofcontingenthistoricalandsocialfactors.Thisseemstobewhatthepursuitofdescriptiveadequacytellsus.Now,ifthiswerethecase,thenthechild’sdatawouldstillbepoor.15Buthowwouldinnateknowledgehelphere?Since,exhypothesi,eachlanguageisasdistinctascanbe,thereisnogeneralitywhichmightbeencodedinthechild’sbrain.Thatis,thechildwouldeffectivelyhavetohaveseparateinnatespecificknowledgeabouteachoftheindefinitenumberoflanguagesitmightacquire.16ThisisjusttofallfoulofthePovertyoftheStimulusArgument:howdoesthechildknowthatthelanguageitisexposedtoisasampleofgrammarXasopposedtoanyoftheothergrammars?Thebestexplanation.Thespecificconjectureisthatweallbeginwithuniversalgrammar(UG),theonelanguage,asitwere.UGisinnateandisinformedinthesensethatitencodescertainoptionsorparameterswhicharesetbyexposuretocertaindata.17ToacquirealanguageissimplyforthevaluesofUG’sparameterstobesetinoneofafinitenumberofpermutations(giventheacquisitionofalexicon.)ChomskyunderstandsUGtobetheinitialstateofthelanguagefaculty(anabstractlyspecifiedsystemofthebrain.)18Toacquirealanguageistoacquireaparticularsystematicmappingbetweensoundandmeaning.Howdowefixateonsuchapairing?Thinkofthelanguagefacultyasageneticallydeterminedinitialstatepriortoexperience.Experiencetriggersthesettingofvaluesalongcertainparametersthatdeterminetheoutputconditions.Experiencealsoprovidestheassignmentoffeaturesinthelexicon,althoughnotthefeat