Announcements Psych 156A/ Ling 150: Acquisition of...

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Psych156A/Ling150:AcquisitionofLanguageII

Lecture16StructureI

Announcements

HW3isduebytheendofclasstoday

Reviewquestionsareavailableforstructure

Onlinecourseevaluationsareavailableforthisclass-pleasefillthemout!:)

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

DependsongrammaticalcategorieslikeNounsandVerbs(andtheirassociatedphrases(NP)),butalsoonmoreprecisedistinctionslikeSubjectsandObjects.

NounVerbNounNPNP

SomeNounPhrasedistinctions:Subject=usuallytheagent/actoroftheaction,“doer”:JarethObject=usuallytherecipientoftheaction,“doneto”:crystals

ComputationalProblem: Figureouttheorderofwords(syntax)

Importantidea:Theobservablewordorderspeakersproduce(likeSubjectObjectVerb)istheresultofasystemofwordorderrulesthatspeakersunconsciouslyusewhentheyspeak.Thissystemofwordorderrulesiscalledsyntax.

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

OnewaytogenerateSubjectVerbObjectorder:Thelinguisticsystemspecifiesthatorderasthegeneralpatternofthelanguage.AnexampleofthiskindofsystemisEnglish.

SubjectVerbObjectEnglish

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

AnotherwaytogenerateSubjectVerbObjectorder:ThelinguisticsystemspecifiesSubjectObjectVerbasthegeneralpattern,buttheVerbinmainclausesmovestothesecondpositionandsomeotherphrase(liketheSubject)movestothefirstposition.AnexamplelanguagelikethisisGerman.

German SubjectObjectVerb

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

____ VerbSubjectObjectVerb

movementrules

AnotherwaytogenerateSubjectVerbObjectorder:ThelinguisticsystemspecifiesSubjectObjectVerbasthegeneralpattern,buttheVerbinmainclausesmovestothesecondpositionandsomeotherphrase(liketheSubject)movestothefirstposition.AnexamplelanguagelikethisisGerman.

German

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

SubjectVerbSubjectObjectVerb

movementrules

AnotherwaytogenerateSubjectVerbObjectorder:ThelinguisticsystemspecifiesSubjectObjectVerbasthegeneralpattern,buttheVerbinmainclausesmovestothesecondpositionandsomeotherphrase(liketheSubject)movestothefirstposition.AnexamplelanguagelikethisisGerman.

German

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

AthirdwaytogenerateSubjectVerbObjectorder:ThelinguisticsystemspecifiesSubjectObjectVerbasthegeneralpattern,buttheObjectmovesaftertheVerbincertaincontexts(theObjectisunexpectedinformation).Kannadaisalanguagelikethis.

Kannada SubjectObjectVerb

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

Kannada SubjectObjectVerbObject

movementrule

AthirdwaytogenerateSubjectVerbObjectorder:ThelinguisticsystemspecifiesSubjectObjectVerbasthegeneralpattern,buttheObjectmovesaftertheVerbincertaincontexts(theObjectisunexpectedinformation).Kannadaisalanguagelikethis.

SubjectVerbObjectJarethjugglescrystals

SubjectVerbObject SubjectVerbSubjectObjectVerb

EnglishGerman

Kannada

SubjectObjectVerbObject

ComputationalProblem: Figureouttheorderofwords(syntax)

Thelearningproblem:Howdochildrenknowwhichsystemtheirlanguageuses?

SubjectVerbObjectJarethjugglescrystals

ComputationalProblem: Figureouttheorderofwords(syntax)

Thisisahardquestion!

Childrenonlyseetheoutputofthesystem(theobservablewordorderofSubjectVerbObject).

SubjectVerbObject SubjectVerbSubjectObjectVerb

EnglishGerman

Kannada

SubjectObjectVerbObject

SubjectVerbObjectJarethjugglescrystals

Syntax:Onereasonwhytranslationissohard

Translationisnotsoeasy: morethanjustword-by-word

http://www.nbc.com/nbc/The_Tonight_Show_with_Jay_Leno/headlines/

Hebrew

Translationisnotsoeasy: morethanjustword-by-word

Literally:Throughdangersimmenseanddifficultiesnotnumbered,there-isto-mefightingthroughmyherecastletransitioncitygoblintakebackyouchildthere-wasto-youstolen.

translate.google.com

HaitianCreole

Translationisnotsoeasy: morethanjustword-by-word

Literally:Throughdangercountlessanddifficultiescountless,IwasfighthowmeheretheymansionthemorefarthancitiestheGoblintheytakebackchildrenofthatyouwasthiefit.

translate.google.com

Hindi

Translationisnotsoeasy: morethanjustword-by-word

Literally:Untoldanduncountabledifficultiesthreatsmediumthrough,Iyoustoleisthatchildrenbacktaketheghostcitybeyondpalacethehereyourmethodsfromfightfought.

translate.google.com

Abouthumanknowledge:Language&variation

NavajoCodeTalkers

http://en.wikipedia.org/wiki/Code_talker#Use_of_Navajo

“…JohnstonsawNavajoasansweringthemilitaryrequirementforanundecipherablecode.NavajowasspokenonlyontheNavajolandsoftheAmericanSouthwest,anditssyntaxandtonalqualities,nottomentiondialects,madeitunintelligibletoanyonewithoutextensiveexposureandtraining.OneestimateindicatesthatattheoutbreakofWorldWarIIfewerthan30non-Navajoscouldunderstandthelanguage….”

https://www.youtube.com/watch?v=5rSvm3m8ZUA(~3minvideo)

CrucialcryptographicmethodusedinWorldWarII

NavajoCodeTalkerParadox(Baker2001)

EnglishmustbeverydifferentfromNavajoJapanesecoulddecodeEnglish,butcouldn’tdecodeNavajowhentheydidn’tknowitwasNavajo.

EnglishmustbesimilartoNavajoEnglishcanbetranslatedintoNavajoandbackwithnolossofmeaning.(Languagesarenotjustaproductoftheculture-pastoralArizonalifestylecouldn’thavepreparedthecodetalkersforPacificIslandhightechwarfare.Yet,translationwasstillpossible.)

Morphology(wordforms)English:invariantwordforms “thegirliscrying”,“Iamcrying”

Navajo:noinvariantforms(theremaybe100-200prefixesforverbstems)

At’éédyicha.“Girlcrying”

Yishcha.“Iamcrying”(yi+sh+cha)

Ninááhwiishdlaad.“Iamagainplowing”(ni+náá+ho+hi+sh+l+dlaad)

Typesofvariation

Wordorder(syntax)English:SubjectVerbObject(invariantwordorder) “Theboysawthegirl”

Navajo:SubjectObjectVerb,ObjectSubjectVerb(varyingwordorders,meaningdependsonlyonverb’sform)

Ashkiiat’éédyiyiiltsáboygirlsaw“Theboysawthegirl”

Ashkiiat’éédbiilstáboygirlsaw“Thegirlsawtheboy”

Typesofvariation

wals.info:TheWorldAtlasofLanguageStructures

Typesofvariation

Let’slookatsyntax…

Jacklaughs.

LaughsJack.ThistellsusthatmostlanguageshavetheSubjectcomebeforetheVerb…butnotalldo.

Typesofvariation

HowarethedifferentSubjectandVerbordersdistributedaroundtheworld?

Let’slookatsyntax…

Typesofvariation

WhatvaluedoesEnglishhave?

WhataboutFijian?

WhataboutSpanish?

Let’slookatsyntax…

Typesofvariation

Thinkingaboutsyntacticvariation

Similarities&differences:Parameters

Chomsky:Differentcombinationsofdifferentbasicelements(parameters)wouldyieldtheobservablelanguages(similartothewaydifferentcombinationsofdifferentbasicelementsinchemistryyieldmanydifferent-seemingsubstances).

Similarities&differences:Parameters

BigIdea:Arelativelysmallnumberofsyntaxparametersyieldsalargenumberofdifferentlanguages’syntacticsystems.

5differentparametersofvariation

Similarities&differences:Parameters

BigIdea:Arelativelysmallnumberofsyntaxparametersyieldsalargenumberofdifferentlanguages’syntacticsystems.

2differentparametervaluesofoneparameter

Similarities&differences:Parameters

BigIdea:Arelativelysmallnumberofsyntaxparametersyieldsalargenumberofdifferentlanguages’syntacticsystems.

Totallanguagesthatcanberepresented=2*2*2*2*2=25=32

Similarities&differences:Parameters

BigIdea:Arelativelysmallnumberofsyntaxparametersyieldsalargenumberofdifferentlanguages’syntacticsystems.

Similarities&differences:Parameters

English

French

Japanese

Navajo

Tagalog

BigIdea:Arelativelysmallnumberofsyntaxparametersyieldsalargenumberofdifferentlanguages’syntacticsystems.

Learninglanguagestructure

Chomsky:Childrenarebornknowingtheparametersofvariation.ThisispartofUniversalGrammar.Inputfromthenativelinguisticenvironmentdetermineswhatvaluestheseparametersshouldhave.

English

Learninglanguagestructure

Chomsky:Childrenarebornknowingtheparametersofvariation.ThisispartofUniversalGrammar.Inputfromthenativelinguisticenvironmentdetermineswhatvaluestheseparametersshouldhave.

Japanese

Learninglanguagestructure

Chomsky:Childrenarebornknowingtheparametersofvariation.ThisispartofUniversalGrammar.Inputfromthenativelinguisticenvironmentdetermineswhatvaluestheseparametersshouldhave.

Navajo

Learninglanguagestructure

Chomsky:Childrenarebornknowingtheparametersofvariation.ThisispartofUniversalGrammar.Inputfromthenativelinguisticenvironmentdetermineswhatvaluestheseparametersshouldhave.

Generalizationsaboutlanguagestructure

Greenberg’swordordergeneralizations

Navajo Japanese Navajo Japanese

Basicwordorder:SubjectObjectVerb

Ashkiiat’éédyiyiiltsáboygirlsaw

“Theboysawthegirl”

Basicwordorder:SubjectObjectVerb

Jareth-gaHoggle-obuttaJarethHogglehit

“JarethhitHoggle”

Greenberg’swordordergeneralizations

Navajo Japanese

Postpositions:NounPhrasePostposition

‘éé’biihnáásdzáclothingintoI-got-back“Igotbackinto(my)clothes.”

Postpositions:NounPhrasePostposition

Jareth-gaSarahtokurumadaJarethSarahwithcarby

LondonniittaLondontowent

“JarethwenttoLondonwithSarahbycar.”

Greenberg’swordordergeneralizations

Navajo Japanese

PossessorbeforePossessed

PossessorPossession

Chidíbi-jáádCarits-leg

“thecar’swheel”

PossessorbeforePossessed

PossessorPossession

Toby-noimooto-gaToby’ssister

“Toby’ssister”

Greenberg’swordordergeneralizations

Navajo Japanese

Basicwordorder:SubjectObjectVerb

Basicwordorder:SubjectObjectVerb

Postpositions:NounPhrasePostposition

Postpositions:NounPhrasePostposition

PossessorbeforePossessedPossessorPossession

PossessorbeforePossessedPossessorPossession

Despitethedifferencesinthelanguages(andtheirculturalhistories),bothJapaneseandNavajoareverysimilarwhenviewedthroughthesethreestructuraldescriptions.

Greenberg’swordordergeneralizations

English Edo(Nigeria)

Greenberg’swordordergeneralizations

English Edo(Nigeria)

Basicwordorder:SubjectVerbObject

SarahfoundToby

Basicwordorder:SubjectVerbObject

ÒzómiénAdésuwá OzofoundAdesuwa

Greenberg’swordordergeneralizations

English Edo(Nigeria)

Prepositions:PrepositionNounPhrase

JarethgavethecrystaltoSarah

Prepositions:PrepositionNounPhrase

ÒzórhiénénéebénéAdésuwáOzogavethebooktoAdesuwa

Greenberg’swordordergeneralizations

English Edo(Nigeria)

PossessedbeforePossessor

PossessionPossessor

questofSarah

(alternative:Sarah’squest)

PossessedbeforePossessor

PossessionPossessor

OmoOzóchildOzo

“childofOzo”

Greenberg’swordordergeneralizations

English Edo(Nigeria)

Basicwordorder:SubjectVerbObject

Basicwordorder:SubjectVerbObject

Prepositions:PrepositionNounPhrase

Prepositions:PrepositionNounPhrase

PossessedbeforePossessorPossessionPossessor

PossessedbeforePossessorPossessionPossessor

Again,despitethedifferencesinthelanguages(andtheirculturalhistories),bothEnglishandEdoareverysimilarwhenviewedthroughthesethreestructuraldescriptions.

Greenberg’swordordergeneralizations

Greenbergfoundforty-five“universals”oflanguages-patternsoverwhelminglyfollowedbylanguageswithunsharedhistory(Navajo&Japanese,English&Edo)

Notallcombinationsarepossible-somepatternsrarelyappearEx:SubjectVerbObjectlanguage(English/Edo-like)+postpositions(Navajo/Japanese-like)

Moral:Languagesmaybemoresimilarthantheyfirstappear“onthesurface”,especiallyifweconsidertheirstructuralproperties.

Greenberg’swordordergeneralizations Onepotentialparameter

English Italian

SubjectVerb

“Jarethwillcome.”

SubjectVerbJarethverráJarethwill-come

“Jarethwillcome.”

grammatical grammatical

English Italian

VerbSubjectVerráJarethWill-arriveJareth

“Jarethwillarrive”

*VerbSubject

*WillarriveJareth

ungrammatical grammatical

Onepotentialparameter

English Italian

*Verb

Willcome

VerbVerráHe-will-come

“Hewillcome”

ungrammatical grammatical

Onepotentialparameter

English Italian

SubjectVerb SubjectVerb

VerbSubjectVerb

Thesewordorderpatternsmightbefairlyeasytonotice.TheyinvolvethecombinationsofSubjectandVerbthataregrammaticalinthelanguage.Achildmightbeabletonoticetheprevalenceofsomepatternsandtheabsenceofothers.

Onepotentialparameter

*VerbSubject*Verb

English Italian

Expletivesubjects:wordswithoutcontent(maybemoredifficulttonotice)

Raining.

“It’sraining.”

Piove.It-rains.

“It’sraining.”

Notokaytoleaveoutexpletivesubject“it”.

Okaytoleaveoutexpletivesubject“it”.

Onepotentialparameter

English Italian

That-traceeffectforsubjectquestions

Whodoyouthink(*that)willcome?

Requiresno“that”inembeddedclause,despiteallowing“that”indeclarativesandobjectquestions

Ithink(that)HogglewillsaveSarah.Whodidyouthink(that)Hogglewouldsave?

Onepotentialparameter

CredicheJarethverrá.YouthinkthatJarethwill-come.“YouthinkthatJarethwillcome.”

Checrediche__verrá?Whothink-youthatwill-come?“Whodoyouthinkwillcome?”

Allows“that”intheembeddedclauseofasubjectquestion(anddeclarativeclauses).

Italian

OnepotentialparameterThat-traceeffectforsubjectquestions

English

English Italian

Notokaytoleaveoutexpletivesubject“it”.

Okaytoleaveoutexpletivesubject“it”.

Doesnotrequirespecialactionforembeddedsubjectquestions.

Requiresspecialactionforembeddedsubjectquestions.

SubjectVerb SubjectVerb

VerbSubject*VerbSubject

*Verb Verb

Alltheseinvolvethesubjectinsomeway-coincidence?Idea:No!There’salanguageparameterinvolvingthesubject.

Onepotentialparameter TheValueofParameters:Learningthehardstuffbynoticingtheeasypatterns

Englishvs.Italian:SubjectParameter

English ItalianSubjectVerb SubjectVerb

VerbSubject*VerbSubject

*Verb Verb

EmbeddedSubject-questionformation(easytomiss)

Whodoyouthink(*that)willcome? Checrediche__verrá?Whothink-youthatwill-come?

ExpletivesItrains

Piove.It-rains.

Hardtonotice

Easiertonotice

Englishvs.Italian:SubjectParameter

Bigidea:Ifallthesestructuralpatternsaregeneratedfromthesamelinguisticparameter(e.g.a“subject”parameter),thenchildrencanlearnthehard-to-noticepatterns(likethepatternsofembeddedsubjectquestions)bybeingexposedtotheeasy-to-noticepatterns(liketheoptionaluseofsubjectswithverbs).Thehard-to-noticepatternsaregeneratedbyonesettingoftheparameter,whichchildrencanlearnfromtheeasy-to-noticepatterns.

Children’sknowledgeoflanguagestructurevariationisbelievedbylinguisticnativiststobepartofUniversalGrammar,whichchildrenarebornwith.

TheValueofParameters:Learningthehardstuffbynoticingtheeasypatterns Anotherpossibleparameter

Syntax:theHeadDirectionalityparameter(Baker2001,Cook&Newson1996):headsofphrases(ex:NounsofNounPhrases,VerbsofVerbPhrases,PrepositionsofPrepositionPhrases)areconsistentlyineithertheleftmostorrightmostposition

Japanese/Navajo:Head-Last

VerbPhrase:ObjectVerb

Postpositions:NounPhrasePostposition

VP

NPObject

Verb

PP

NPObject

Ppostposition

Anotherpossibleparameter

Syntax:theHeadDirectionalityparameter(Baker2001,Cook&Newson1996):headsofphrases(ex:NounsofNounPhrases,VerbsofVerbPhrases,PrepositionsofPrepositionPhrases)areconsistentlyineithertheleftmostorrightmostposition

VP

NPObject

Verb

PP

PObjectNP

Preposition

Edo/English:Head-First

VerbPhrase:VerbObject

Prepositions:PrepositionNounPhrase

UniversalGrammar:Parameters

SNP VP

NPObject

Subject Verb

PP

PObjectNP

preposition

Edo/English

SNP VP

NPObject

Subject Verb

PP

NPObject

Ppostposition

Japanese/Navajo

Atthislevelofstructuralanalysis(parameters),languagesdiffervaryminimallyfromeachother.Thismakeslanguagestructuremucheasierforchildrentolearn.Alltheyneedtodoissettherightparametervaluesfortheirlanguage,basedonthedatathatareeasytoobserve.

Butwhatarelinguisticparametersreally?Howdotheywork?Whatexactlyaretheysupposedtodo?

Parameters

Aparameterismeanttobesomethingthatcanaccountformultipleobservationsinsomedomain.

Parameterforastatisticalmodel:determineswhatthemodelpredictswillbeobservedintheworldinavarietyofsituations

Parameterforourmental(andlinguistic)model:determineswhatwepredictwillbeobservedintheworldinavarietyofsituations

Statisticalparameters

Thenormaldistributionisastatisticalmodelthatusestwoparameters:

-µ forthemean -σ forthestandarddeviation

Ifweknowthevaluesoftheseparameters,wecanmakepredictionsaboutthelikelihoodofdatawerarelyorneversee.

Supposethisisamodelofhowmanyminuteslateyou’llbetoclass.

Let’susethemodelwithµ =0,andσ2=0.2.(blueline)

Statisticalparameters

Supposethisisamodelofhowmanyminuteslateyou’llbetoclass.

Let’susethemodelwithµ =0,andσ2=0.2.(blueline)

Howlikelyareyoutobe5minuteslate,giventheseparameters?

Notverylikely!Wecantellthisjustbyknowingthevaluesofthetwostatisticalparameters.Theseparametervaluesallowustoinfertheprobabilityofsomeobservedbehavior.

StatisticalparametersObservingdifferentquantitiesof

datawithparticularvaluescantelluswhichvaluesofμandσ2aremostlikely,ifweknowwearelookingtodeterminethevaluesofμandσ2infunctionφ(X)

Observingdatapointsdistributedlikethegreencurvetellsusthatμislikelytobearound-2,forexample.

Statisticalparameters

Statisticalvs.LinguisticparametersImportantsimilarity: Wedonotseetheprocessthat

generatesthedata,butonlythedatathemselves.ThismeansthatinordertoformourexpectationsaboutX,weare,ineffect,reverseengineeringtheobservabledata.

Ourknowledgeoftheunderlyingfunction/principlethatgeneratesthesedata-φ(X)-aswellastheassociatedparameters-μ,andσ2-allowsustorepresentaninfinitenumberofexpectationsaboutthebehaviorofvariableX.

Linguisticprinciplesvs.linguisticparameters

Bothprinciplesandparametersareoftenthoughtofasinnatedomain-specificabstractionsthatconnecttomanystructuralpropertiesaboutlanguage.

Linguisticprinciplescorrespondtothepropertiesthatareinvariantacrossallhumanlanguages.Comparison:theequation’sform–itisthestatistical“principle”thatexplainstheobserveddata.

Bothprinciplesandparametersareoftenthoughtofasinnatedomain-specificabstractionsthatconnecttomanystructuralpropertiesaboutlanguage.

Linguisticparameterscorrespondtothepropertiesthatvaryacrosshumanlanguages.Comparison:μandσ2determinetheexactformofthecurvethatrepresentsthelikelihoodofobservingcertaindata.Whiledifferentvaluesfortheseparameterscanproducemanydifferentcurves,thesecurvessharetheirunderlyingformduetothecommoninvariantfunction.

Linguisticprinciplesvs.linguisticparameters Theutilityofconnectingtomultipleproperties

Thefactthatparametersconnecttomultiplestructuralpropertiesthenbecomesaverygoodthingfromtheperspectiveofsomeonetryingtoacquirelanguage.Thisisbecauseachildcanlearnaboutthatparameter’svaluebyobservingmanydifferentkindsofexamplesinthelanguage.

“Thericherthedeductivestructureassociatedwithaparticularparameter,thegreatertherangeofpotential‘triggering’datawhichwillbeavailabletothechildforthe‘fixing’oftheparticularparameter”–Hyams(1987)

Theutilityofconnectingtomultipleproperties

Parameterscanbeespeciallyusefulwhenachildistryingtolearnthethingsaboutlanguagestructurethatareotherwisehardtolearn,perhapsbecausetheyareverycomplexpropertiesthemselvesorbecausetheyappearveryinfrequentlyintheavailabledata.

Whyhard-to-learnstructuresareeasier

Let’sassumeanumberofpropertiesareallconnectedtoparameterP,whichcantakeoneoftwovalues:aorb.

P1P2P3

P4

P5

P aorb?

HowdowelearnwhetherP4showsbehavioraorb?OnewayistoobservemanyinstancesofP4.

P1P2P3

P4

P5

P aorb?

aaaaaaaaaa…

Whyhard-to-learnstructuresareeasier

ButwhatifP4occursveryrarely?WemightneverseeanyexamplesofP4.

P1P2P3

P4

P5

P aorb?

???

Whyhard-to-learnstructuresareeasier

Fortunately,ifP4isconnectedtoP,wecanlearnthevalueforP4bylearningthevalueofP.Alsofortunately,PisconnectedtoP1,P2,P3,andP5.

P1P2P3

P4

P5

P aorb?

???

Whyhard-to-learnstructuresareeasierStep1:ObserveP1,P2,P3,orP5.Inthiscase,alltheobserved

examplesofthesestructuresarebehaviora.

P1P2P3

P4

P5

P aorb?

aaaaaaaaaaaaaa…

???

Whyhard-to-learnstructuresareeasier

Step2:UsethisknowledgetosetthevalueofparameterPtoa.

P1P2P3

P4

P5

P a

aaaaaaaaaaaaaa…

???

Whyhard-to-learnstructuresareeasierStep3:SinceparameterPisconnectedtoP4,wecanpredictthatP4will

alsoshowbehaviora-eventhoughwe’veneverseenanyexamplesofit!(WecanalsoinferP3andP5thesameway.)

P1P2P3

P4

P5

P a

aaaaaaaaaaaaaa…

a

Whyhard-to-learnstructuresareeasier

Whyacquisitioniseasier

Thishighlightsanotherbenefitofparameters-wedon’thavetolearnthebehaviorofeachstructureindividually.Instead,wecanobservesomestructures(ex:P1andP2)andinfertherightbehaviorfortheremainingstructures(P3,P4,andP5).

Thatis,insteadofhavingtomake5decisions(oneforP1,P2,P3,P4,andP5),weactuallyonlyneedtomakeonedecision-isPaorb?

P1P2P3

P4

P5

P a

a

aaaaaaaaaaaaaa…aa

HierarchicalBayesianlearninglinks:Overhypotheses

OverhypothesesinhierarchicalBayesianlearningaregeneralizationsmadeatamoreabstractlevel,whichcovermanydifferentdatatypes.

Inthisway,theyaresimilarinspirittolinguisticparameters.

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Supposeyouareobservingthecontentsofmarblebags.

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Thefirstbagyoulookathas20blackmarbles.

20

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Thesecondbagyoulookathas20whitemarbles.

20 20

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Thethirdandfourthbagsyoulookathave20blackmarbles.

20 20 20 20

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Yougetafifthbagandpulloutasinglemarble.It’swhite.Whatdoyoupredictaboutthecolordistributionoftherestofthemarblesinthebag?

20 20 20 20

1

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Mostadultspredictthisbagwillcontain19otherwhitemarbles,foratotalof20whitemarbles.

20 20 20 20

201

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Whatifyouthengetasixthbagandpulloutasinglepurplemarblefromit?

20 20 20 20

201 1

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Mostadultswouldpredictthattheother19marblesinthatbagarepurpletoo,for20purplemarblestotal.

20 20 20 20

1 20201

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

Whydoesthishappen?Itseemslikeyou’relearningsomethingaboutthecolordistributioningeneral(notjustforaparticularbag):allmarblesinabaghavethesamecolor.Thisallowsyoutomakepredictionswhenyou’veonlyseenasinglemarbleofwhatevercolorfromabag.

20 20 20 20

1 20201

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

20 20 20 20

1 20201observed

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

20 20 20 20

1 20201allblack allwhite allblack allblack

allthesamecoloroverhypothesis

HierarchicalBayesianlearninglinks:Overhypotheses

Overhypothesisexample

20 20 20 20

1 20201allblack allwhite allblack allblack

allthesamecolor makepredictionsoverhypothesis

HierarchicalBayesianlearninglinks:Overhypotheses

Linguisticoverhypothesisexample

Supposeyouareobservingthewordorderofsentencesyouhear.

HierarchicalBayesianlearninglinks:Overhypotheses

Linguisticoverhypothesisexample

ThefirstsentenceyouhearhastheVerbbeforetheObject(“Seethepenguin?”)

VerbObject

HierarchicalBayesianlearninglinks:Overhypotheses

Linguisticoverhypothesisexample

ThesecondsentenceyouhearhasthePrepositionbeforetheObject(“Ilikethepenguinontheiceberg”)andalsotheVerbbeforetheObject(“Ilikethepenguinontheiceberg”).

VerbObject PrepositionObjectVerbObject

HierarchicalBayesianlearninglinks:Overhypotheses

Linguisticoverhypothesisexample

Thesedatatellyouaboutwordorderforverbsandobjectsandalsoaboutwordorderforprepositionsandtheirobjects.

VerbObject PrepositionObjectVerbObject

observed

HierarchicalBayesianlearninglinks:Overhypotheses

Linguisticoverhypothesisexample

Inaddition,theyarerelatedviatheheaddirectionalityparameter,whichfunctionsasanoverhypothesis.

VerbObject PrepositionObject

headfirst headfirst

Headdirectionality=headfirst

VerbObject

HierarchicalBayesianlearninglinks:Overhypotheses

Linguisticoverhypothesisexample

Knowingthevalueofthisparameterallowsyoutopredictotherwordorderpropertiesofthelanguage.

PossessionPossessor

makepredictions

VerbObject PrepositionObject

headfirst headfirst

Headdirectionality=headfirst

VerbObject

HierarchicalBayesianlearninglinks:Overhypotheses

Learningoverhypotheses

Bayesianlearnercomputationalmodelsareabletolearnoverhypotheses,providedtheyknowwhattheparametersareandtherangeofvaluesthoseparameterscantake(ex:Kemp,Perfors,&Tenenbaum2006).

Whataboutreallearners?

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Question: Whenprovidedwithpartialevidenceaboutafew

objectsinafewcategories,caninfantsformamoreabstractgeneralization(anoverhypothesis)thatthenappliestoanewcategory?

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Trainingtrials: Observefourdifferentobjects

pulledoutbyexperimenterwhohadhereyesclosed-theobjectsaredifferentcolorsbutalwayshavethesameshape.

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Experimentaltrials: Expectedoutcome(assuming

infantshadtheoverhypothesisthatalltheobjectsfromasingleboxshouldbethesameshape)=

Experimenterpullsouttwoobjectswiththesamenewshape.

Infantsshouldnotbesurprised.

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Experimentaltrials: Unexpectedoutcome(assuming

infantshadtheoverhypothesisthatalltheobjectsfromasingleboxshouldbethesameshape)=

Experimenterpullsouttwoobjectswithdifferentshapes,onewhichisnewandonewhichisold.

Infantsshouldbesurprised.

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Controltrials: Expectedoutcome(assuming

infantshadtheoverhypothesisthatalltheobjectsfromasingleboxshouldbethesameshape)=

Experimenterpullsouttwoobjectswiththesamenewshape.

Infantsshouldnotbesurprised.

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Controltrials: Unexpectedoutcomecontrol= Experimenterpullsouttwo

objects,onewithanewshapethatcamefromthenewboxandonewithanoldshapethatcamefromanoldboxthatcontainedthatshape.

Infantsshouldnotbesurprisedthisoutcomeiscompatiblewiththeoverhypothesis.(Theoverhypothesisisactuallyirrelevanthere.)

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Results: Infantsintheexperimental

conditionlookedlongerattheunexpectedoutcome(~14.28s)whencomparedtotheexpectedoutcome(~11.32s).

Theyweresurprisedattheevidencethatdidn’tsupporttheoverhypothesis!

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Results: Infantsinthecontrolcondition

didnotlooklongerattheexpectedoutcomeascomparedtotheunexpectedoutcomecontrolthathadthesameobjectspresent(~10.3-11.0s).

Theywerenotsurprisedattheevidencethatwascompatiblewiththeoverhypothesis,eveniftheevidenceinvolvedtwodifferentlyshapedobjects.

Learningoverhypotheses:Dewar&Xu(2010)

9-month-olds

Overallresult:

9-month-oldsappearabletoformoverhypothesesfromverylimiteddatasets.

Hopefully,thismeanstheycanalsouselinguisticparameterstolearn,sinceparametersaresimilartooverhypothesesaboutlanguage!

Summary:Linguisticparameters

Linguisticparametersaresimilartostatisticalparametersinthattheyareabstractionsabouttheobservabledata.Forlinguisticparameters,theobservabledataarelanguagedata.

Parametersmakeacquisitioneasierbecausehard-to-learnstructurescanbelearnedbyobservingeasy-to-learnstructuresthatareconnectedtothesameparameters.

Parametersmaybesimilartooverhypotheses,whichBayesianlearnersand9-month-oldsarecapableoflearning.

Questions?

Youshouldbeabletodoupthroughquestion11onthestructurereviewquestions.

ExtraMaterial

Syntax:Onereasonwhynaturallanguagecomprehensionissohardforcomputers

SolvingtheLanguageProblem(ArtificialIntelligence)

HAL9000from2001:ASpaceOdyssey(1968)

PerfectproductionandcomprehensionofEnglish.

1960s:Languagenotconsideredoneofthe“hard”problemsofartificialintelligence.

2010:Gettingbetterbutstillnotperfect.

http://www.research.att.com/~ttsweb/tts/demo.php

http://bits.blogs.nytimes.com/2012/07/15/with-apple’s-siri-a-romance-gone-sour/?_php=true&_type=blogs&_r=0

SolvingtheLanguageProblem(ArtificialIntelligence)

2012:Apple’sSiriisgettingcloser,thoughstillhasproblems…

SolvingtheLanguageProblem(ArtificialIntelligence)

Contrast:Chess-playing.

In1997,aprogramnamedDeepBluebeatthereigningworldchampioninchess.Itdidthisbyhavingenoughcomputationalresourcestoinvestigateeverymoveoptionbeforeitactuallymadethechessmove.Thisshowsthatcomputers’poorperformanceonlanguageisnotaboutinsufficientcomputationalpower,sincethereisenoughcomputationalpowertosolvethechess-playingproblem(whichsomepeoplemightconsideraverydifficultproblem).

SolvingtheLanguageProblem(ArtificialIntelligence)

Updatefor2011onamachine’sabilitiestodowhathumansdo:

Manvs.Machine(Watson)inJeopardy&howhardaproblemlanguagecomprehensionandproductionis

http://www.youtube.com/watch?v=dr7IxQeXr7g(approximately9minvideo)

Watsonvs.allhumanityh~ps://www.youtube.com/watch?v=WFR3lOm_xhE(approximately4minvideo)

“We'res�llveryfarfromprogramswithcommonsense-AIthatcananswercomprehensionques�onswiththeskillofachildof8,"saidSloan.Heandhiscolleagueshopethestudywillhelptofocusa~en�ononthe"hardspots"inAIresearch.

http://www.sciencedaily.com/releases/2013/07/130715151059.htm

SolvingtheLanguageProblem(ArtificialIntelligence)

2013:Trueon-the-flylanguagecomprehensionisstillprettyhard,aswellasdeterminingtheanswerto“commonsense”questionsthatarephrasednaturally.

“Oneofthehardestproblemsinbuildinganar�ficialintelligence,Sloansaid,isdevisingacomputerprogramthatcanmakesoundandprudentjudgmentbasedonasimplepercep�onofthesitua�onorfacts-thedic�onarydefini�onofcommonsense.

CommonsensehaseludedAIengineersbecauseitrequiresbothaverylargecollec�onoffactsandwhatSloancallsimplicitfacts—thingssoobviousthatwedon'tknowweknowthem.Acomputermayknowthetemperatureatwhichwaterfreezes,butweknowthaticeiscold.”-JeanneGalatzer-Levy

Typesofvariation

VocabularyEnglish“think”verbs:think,know,wonder,suppose,assume,…

Multipletypesoftheactionverb“think”.Eachhascertainusesthatareappropriate.

“Iwonderwhetherthegirlsavedherlittlebrotherfromthegoblins.”[grammatical]

*“Isupposewhetherthegirlsavedherlittlebrotherfromthegoblins.”[ungrammatical]

VocabularyEnglish“think”verbs:think,know,wonder,suppose,assume,…Navajo“carry”verbs:dependsonobjectbeingcarriedaah(carryasolidround-ishobject)

kaah(carryanopencontainerwithcontents)

lé(carryaflexibleobject)

TypesofvariationSounds:EachlanguageusesaparticularsubsetofthesoundsintheInternationalPhoneticAlphabet,whichrepresentsallthesoundsusedinallhumanlanguages.There’softenoverlap(ex:“m”,“p”areusedinmanylanguages),butlanguagesalsomaymakeuseofthelesscommonsounds.

lesscommonEnglishsounds:“th”[T], “th”[D] lesscommonNavajosounds:“whisperedl”,“nasalizeda”,…

Typesofvariation