Evidence for Item Based Development

Slide 1:Evidence for Item Based Development

E. Bates and J. C. Goodman, On the Emergence of Grammar From the Lexicon M. Tomasello, The item-based nature of children's early syntactic development

Slide 2:Evidence for Item Based Development

Introduction What is item-based development? Studies in Lexically Based Grammar Studies in Item Based Development Conclusion

Slide 3:Introduction

What is Item Based Development? Hypothesis: children�s early utterances are organized around particular words and phrases. Speech is not abstract So why is early speech perceived as grammatical? Children imitate and reproduce adult utterances, appearing to posses a knowledge of grammar

Slide 4:Introduction

Item based nature is most evident in the use of verbs Children tend to retain sampled sentence structure for each particular verb, hence: A child might use �cut� in the schema Cut___ alone The same child will use in more complex schemas for �draw� like Draw___, Draw___on____,Draw___for___ When children learn the determiners a and the, they use each with a different set of nouns, usually mutually exclusive The cat The house The � a dog a plate a �

Slide 5:Introduction

Studies in Italian regarding verb use show that: 47% of all verbs used, were used in one form only 40% were used in two or three forms The remaining 13% were highly irregular forms (frequently used by adults), which could not be learned from generalization Study group were 3 children, aged 18 months to 3 years The verbs in question had 6 possible forms (first person singular, second person singular etc�)

Slide 6:Introduction

Transitive and Intransitive Transitive (Subject-Verb-Object) Intransitive (Subject-Verb) Can children use verbs they�ve heard in an intransitive context in a transitive way? Experiment Children were introduced a novel verb with a picture. For example �The sock is tamming� with a matching cartoon

Slide 7:Introduction

Later, they were encouraged, with another cartoon, to reply to the question �What is doggie doing?� We could expect the child to say something like �The doggie is tamming the car� This would be creative, as the child has taken a novel verb, and taken it into a new, transitive, context Very few children produced the transitive reply As a control for these results, other children were exposed to the transitive form, and they had no trouble reproducing it We�ll return to these studies later

Slide 8:Introduction

Why should we care? Chomsky�s nativist approach claims Language acquisition takes place quickly and effortlessly because children have full linguistic competence at birth Language acquisition relies only indirectly on the language they are exposed to Children are creative in early stages, because of innate grammar proficiency Item based development disagrees with this, and questions the presence of adult grammar in children�s language

Slide 9:Definitions

Grammar Grammar is the discovery, enunciation, and study of rules governing the use of language. The set of rules governing a particular language is also called the grammar of the language.Or as previously described: A set of sentences with a finite structural description. Lexicon What words are, how the vocabulary in a language is structured, how people use and store words, how they learn words, the history and evolution of words, types of relationships between words as well as how words are created. Lexicon is a word of Greek origin (?e?????) meaning vocabulary

Slide 10:First Debate

Grammar from the Lexicon What does this mean? Grammar has vocabulary qualities Grammar and vocabulary are learned the same Same mental mechanisms used for both Chomsky Grammar cannot be learned! (in finite time) It is different from vocabulary

Slide 11:Nature of Debate

Epistemology Empiricism Vs. Nativism Plato Vs. Aristotle Do we have a special grammar organ, or are we just really smart? Really smart = innate abilities not specific to language Soft empiricist claim

Slide 12:Emergentism

Emergentism Solutions to a problem are unpredictable We will explore the Emergentist approach Emphasizing the union between grammar and lexicon

Slide 13:The Giraffe

Is the giraffe�s neck a �leaf eating organ�? Is the giraffe itself a leaf eating organ?

Slide 14:Humans and Giraffes

Hypotheses: Human grammar has evolved like the giraffe�s neck Human beings have walked into a problem space that other animals cannot perceive Appearance of language applied pressure on neural mechanisms in the brain So� Human beings have symbols for everything When these symbols appeared together, grammar emerged

Slide 15:Evidence

Two types of evidence grammar and the lexicon same mental systems (neural mechanism) Strong relation between grammar/lexical development Overlap in symptoms of brain damage The same mental systems for grammar and the lexicon have other roles Same mental systems do other things

Slide 16:Evidence for Item Based Development

Introduction Studies in Lexically Based Grammar Normal Children Atypical Populations Lexicon and Grammar in the Adult Brain Studies in Item Based Development Conclusion

Slide 17:Studies

Research in normal children Relation between lexical development and grammar complexity Target group: normal children, 8 to 30 months of age Early language development in atypical populations Comparison with normal children Early/late talkers, focal brain injury, Williams and Down Syndrome, SLI

Slide 18:Studies

Grammar and lexicon in the adult brain Does modularization occur in a later stage? We will examine neurological patients

Slide 19:Development in Normal Children

General Maturation of speech development (English) Phonology (reduplicative babbling) - 6 to 8 months Meaningful speech � 10 to 12 months Additional 4 to 8 months in one word stage Burst in vocabulary growth (combinations) - 16 to 20 months Second burst, morphological � 24 to 30 months Mastering of morphological and syntactic structures � 3 to 3.5 years Appears like maturation of three mental modules Phonological Lexical Grammatical

Slide 20:Grammar, Comprehension Production

Zones of acceleration for each domain are separated by many weeks Lets try and find a connection

Slide 21:Vocabulary and MLU

Correlation between vocabulary and MLU Best indication for 28 month MLU is 20 month vocabulary Correlation is not cause

Slide 22:Cross Sectional Grammar Complexity

Individual differences around the grammar on vocabulary function are rather small (small s.d.)

Slide 23:Grammar and Expressive Vocabulary

Tight correlation between grammar and vocabulary Clear dissociation between words comprehended and words produced

Slide 24:Grammar and Expressive Vocabulary

Fan shaped pattern Implies that word comprehension is a prerequisite for expressive grammar not sufficient Comprehension and production can dissociate Grammar We expect vocabulary to put a ceiling on grammar complexity, until a threshold is reached grammar will then decouple with vocabulary Instead, grammar and vocabulary remain tightly coupled

Slide 25:Important Points

Study follows children through critical stage in development Is the correlation we found a correlation of grammar with itself? Vocabulary includes many prepositions, articles and other grammatical words Removal of such words yields close results Similar study conducted in Italian Similar results

Slide 26:Longitudinal Study

We can see that the link between grammar and lexical development extends to longitudinal studies as well

Slide 27:Explaining the Link

Perceptual bootstrapping Grammatical function words are short, low in stress and difficult to perceive Logical bootstrapping Children cannot understand relational terms, until they understand what they relate to. So, grammar depends on the lexicon Syntactic bootstrapping Children exploit sentential information to extract the meaning of a novel word. Grammar words are thus obtained

Slide 28:Explaining the Link

Nonlinear dynamics of learning in a neural network Experiments in neural network learning (even past tense learning) has resulted in non-linear curves Lexically based grammar The relation observed would be exactly what we would expect, if grammar is part of the lexicon

Slide 29:Development in Atypical Populations

We would like to find a pediatric population which displays a dissociation between grammar and the lexicon We shall examine Late and early talkers Early focal lesions Williams Syndrome and Down Syndrome Specific Language Impairment (SLI)

Slide 30:Late and Early Talkers

Late talkers Children of age 18 to 24 months who are in the bottom 10th percentile for expressive vocabulary Early talkers Children of age 12 to 24 months who are in the top 10th percentile for expressive vocabulary Do grammar and vocabulary dissociate in these two groups?

Slide 31:Late and Early Talkers

Grammar-on-vocabulary function for two children Age 16 to 30 months Age is a poor predictor of vocabulary and grammar

Slide 32:Two Case Studies

Slide 33:Two Case Studies

MW 17 months old, expressive vocabulary 596 words, MLU 2.13 SW 21 months old, expressive vocabulary 627 words, MLU 1.12 Deductions It appears that SW is lagging in grammatical development (just begun combining words). Possible dissociation Despite huge vocabulary, her grammatical level is average for her age However, SW displays advanced morphology (knows falling and fell) Dissociation could be explained by short auditory memory We will use this argument again

Slide 34:Early Focal Lesions

Assuming different neural mechanisms for grammar and vocabulary We expect to find dissociation between grammar and lexicon, in relation to congenital(Present at birth) brain injuries We also expect conformity with classic adult aphasia studies (discussed later) Delay in grammar development for left frontal damage (Broca�s area) Delay in lexical development for posterior left damage (Wernicke�s area)

Slide 35:Early Focal Lesions

No evidence in favor of predictions With older children Plastic reorganization of brain for early focal lesions Studies conducted during first stages of language acquisition might prove insightful Lesion site has impact on lingual development Target group: 10 months to 12 years

Slide 36:Classic Language Areas

Adults suffering damage to Broca�s area usually display inability to produce or comprehend grammatically complex sentences Damage to Wernicke�s area usually manifests in impairment of comprehension, and natural sounding speech without meaning

Slide 37:Early Focal Lesions

Absence of left right differences Absence of global differences Small but reliable disadvantage in word comprehension for right focal damage Wernicke�s area Left temporal cortex Delayed in expressive language (10 to 60 months) Reliable disadvantage Broca�s area No effects recorded for Broca�s Area Front damage is symmetric for right and left (during 19 to 31 months period) Conclusion: temporal lobe of left hemisphere is critical, but the frontal lobes become involved in later stages

Slide 38:Early Focal Lesions

Disappearance of left temporal effect Children with (any) early focal lesion rank below average at the age of 5 to 7 years Left lesion disadvantage disappears at this age, indicating that some plastic reorganization has taken place (the discussed Wernicke�s area)

Slide 39:Conclusions For Early Focal Lesions

Study group ranks well within 10th to 90th percentile of normal population in grammar-on-vocabulary function In a normal group of 19 children, we would also expect 1-4 children in the outskirts

Slide 40:Williams Vs. Down

Williams (WMS) and Down (DNS) syndromes Both constitute a form of genetically based mental retardation Mean IQ�s between 40 and 60 Contrast in grammar development Down Language abilities below mental age Severe function word omissions and structural simplifications Williams Below mental age Language abilities surprisingly good compared with other mental abilities

Slide 41:Williams Vs. Down

When do groups separate? Both groups are late talkers, seriously delayed in word comprehension and production during the infant scale (8 to 16 months in normal children) Though still 2 years delayed in vocabulary, during toddler scale (16 to 30 months in normal children), WMS children display good grammar capabilities (Within 10th to 90th percentiles) DNS children remain at a disadvantage First evidence of dissociation WMS usually score low on visual short term memory DNS usually score low on auditory short term memory A result of perceptual impairment?

Slide 42:Williams Vs. Down

Slide 43:Specific Language Impairment

Definition: A delay in expressive language abilities that is 1 standard deviation below average The term specific may be misleading Low attention span also diagnosed Studies show that grammatical morphology is highly effected This dissociation can also be explained by a difficulty of processing rapid auditory data

Slide 44:Grammar and Lexicon in the Adult Brain

Conclusions at this point We�ve seen an interdependence between grammar and lexicon compatible with unified grammar/lexical approach Adult neural mechanisms Does modularization occur in later stages This is not incompatible with findings so far We will present two kinds of evidence Neural imaging of lexical and grammatical processing Dissociation between lexicon and grammar in patients with focal brain injury (or lack of)

Slide 45:Grammar and Lexicon in the Adult Brain

Some points to keep in mind All knowledge is in the brain Short of finding neural activity at birth, can�t know source of knowledge (innate/acquired) Differences in experience must be accompanied in differences in neural activity Different responses to two classes of stimuli would require these classes be associated with different patterns in the brain Different brain activity accounted for Nouns vs. Verbs Animal words Vs. Tool Words High/low frequency words Classifying by brain activity would result in two many �systems� Difficulty in classifying by neural activity

Slide 46:Grammar and Lexicon in the Adult Brain

Localization and domain specificity are not the same If an area is used for language processing, it does not imply dedication Difficult to prove negative things (like dedication) Broca�s area known to mediate some motor tasks as well as language

Slide 47:Definitions

Aphasia Aphasia is a loss or impairment of the ability to produce or comprehend language, due to brain damage. It is usually a result of damage to the language centres of the brain (like Broca�s area).

Slide 48:Different Arguments

Neural Imaging So far no convincing study conducted Evidence of dissociation between grammar and lexicon exist, but vary from study to study Adult aphasia presents a more interesting challenge Damage to Broca�s area known to create grammatical difficulties Is Broca�s area central for grammar processing? Damage to Broca�s area results in processing impairments that transcend language

Slide 49:All Aphasic Patients have Lexical Difficulties

Anomia Deficit in word retrieval All Aphasic patients have some sort of Anomia Hence, a grammar deficit is always accompanied by a lexical deficit

Slide 50:Expressive Agrammatism

Studies in English show that patients of Broca�s aphasia suffer from agrammatism, while Wernicke�s aphasia patients do not Agrammatism for Wernicke�s aphasia only detected in highly inflected languages (like German and Czech) English is poor in inflections So, the above hypotheses is a result of studies conducted in English! The following table summarizes agrammatism in different populations

Slide 51:Expressive Agrammatism

Slide 52:Similar Symptoms

Review of the table reveals that Patients with agrammatical symptoms, have similar symptoms relating to the lexicon Patients with omission pattern in grammar, have word retrieval failures (common in Broca�s aphasia) Patients who display word substitution in grammar (in instead of at) also display substitution in vocabulary (paraphasia). Common to Wernicke�s and WMS Etc Results suggest that grammatical and lexical deficits have common cause

Slide 53:Receptive Agrammatism

Receptive agrammatism Is characterized by a difficulty of processing inflections and closed-class words. More difficulties with non-canonical word order types For example The rabbit is being thrown by the bear is more difficult than the bear is throwing the rabbit present in normals as well, under the influence of noise, or other interference Closed-class words � part of the vocabulary of a language that isn�t likely to change (such as pronouns)

Slide 54:Receptive Agrammatism

Not unique to aphasia populations, present in normals under adverse conditions

Slide 55:Evidence for Item Based Development

Introduction Studies in Lexically Based Grammar Studies in Item Based Development Investigating children�s verb usage Building a Usage Based Model Conclusion

Slide 56:Recalling Previous Experiment

Transitive and Intransitive Transitive (Subject-Verb-Object) Intransitive (Subject-Verb) Can children use verbs they�ve heard in an intransitive context in a transitive way? Experiment Children were introduced a novel verb with a picture. For example �The sock is tamming� with a matching cartoon Later, they were encouraged, with another cartoon, to reply to the question �What is doggie doing?�

Slide 57:Recalling Previous Experiment

The above experiment was conducted with children aged 2-3 years old Other studies have shown that children of age 3-4, have no difficulty assimilating a novel verb and using it creatively

Slide 58:Similar Experiments in English

Novel verbs were presented in different sentence frames Presentational construction (This is called groping) Imperative construction (Tam, Anna!) Passive construction (Ernie is getting meeked by the dog) The children were encouraged to produce transitive sentences Children under the age of 3 were very poor in creative constructions

Slide 59:Inducing non-Grammatical English

Presenting 3 novel verbs Age groups: 2;8, 3;6, 4;4 Verbs introduced One in normal SVO (transitive) form Ernie meeking the car One in SOV form Ernie the car tamming One in VSO form Gropping Ernie the car Almost everyone produced SVO forms with the verb they heard in that form When encouraged to use the incorrect forms The older children corrected the verb to normal transitive form The younger children generally produced the illegal forms in which the verb was introduced These results are inconsistent with an innate proficiency in grammar

Slide 60:Additional Attempts

Key to Graph

Slide 61:Additional Attempts

As we can see, creativity improves with age

Slide 62:Two Supporting Facts

Perhaps young children are reluctant to use novel words in novel ways? Studies show that children freely use novel nouns in novel sentence frames Perhaps children have production difficulties? Children participating in the studies proved no better in comprehension, than they did in production

Slide 63:Introduction

As we�ve seen, the above results contradict Chomsky�s nativist approach Chomsky�s nativist approach claims that Language acquisition takes place quickly and effortlessly because children have full linguistic competence at birth Language acquisition relies only indirectly on the language they are exposed to. Children are creative in early stages, because of innate grammar proficiency

Slide 64:Possible Nativist Retorts

Performance Limitations Children have performance limitations that inhibit the expression of innate knowledge However: children display no limitations when learning new nouns, or reproducing familiar sentence frames with novel verbs Genes for adult like grammar turn on later Perhaps early speech is item-based, but appropriate �brain circuits� turn on at later stages Problem: All the above experiments were conducted on the English transitive form, which children could produce with other verbs

Slide 65:Usage Based Model

Nativist model is lacking At odds with empirical data A new model is needed Usage Based Model This approach tends to characterize a child�s language in terms of cognitive and communicative processes involved Children begin categorizing concrete nouns quite early Only later do children analyze the syntactic structure of their item-based constructions Adult end point Instead of abstract grammar, we have an inventory of symbolic resources This resembles the lexically based grammar we spoke of earlier

Slide 66:Usage Based Model

Processes involved Imitative learning Children reproduce adult utterances, but not only reproduce, but for the same communicative purpose (they recognize it has meaning) Imitative learning for all constructions Children find abstract categories and schemas Children find patterns Done in concrete nouns quite early (Daddy�s car into Daddy�s_____) Children see both structural and functional similarities in sentences like dad kisses mommy, I hit Jeffery Hypothesis: a critical mass of verbs is necessary

Slide 67:Usage Based Model

Processes (continued�) Children combine structures and schemas For example, the child combines See___(Mommy/Ball) with Daddy�s___(Car) into See daddy�s car Child must realize, that Daddy�s car is somehow equivalent to Mommy or Ball

Slide 68:Evidence for Item Based Development

Introduction Studies in Lexically Based Grammar Studies in Item Based Development Conclusion Grammaticalization Lexically based grammar

Slide 69:Conclusion

So we reject the Nativist Account Where does language come from? Hypothesis Grammatical structures do not come from the human genome Children do not invent grammar A reasonable theory would be that once the homo sapiens learned symbolic communication, a string of successive symbols began to take form. This is called Grammaticalization Grammaticalization processes are well attested to in literature of the recent past

Slide 70:Grammaticalization

What is it The inventory of symbolic conventions is universal (the existence of a past, all humans have hands etc.) Peculiarities of each language are governed by what that community thinks it�s important to talk about The structures and conventions of a language evolve, adapt and change. This is called Grammaticalization

Slide 71:Examples

From English The future tense with the word will (used for volition). �I will it to happen� turns to �It will happen� Go was used to indicate movement, so �I am going to the store� turned into �I am going to sleep� The past perfect tense, with have, is most likely to have derived from sentences like �I have a broken finger�, turning into �I have broken a finger� Phrases like �On the top of� or �In the side of� turn into �On top of� or �Inside of�, eventually reducing to �atop� or �inside�

Slide 72:Conclusion

So how do we account for abstraction? Chomsky noted that abstraction must be contributed from the individual child�s mind (The sentences themselves are not abstract) It is difficult to imagine children applying abstract properties to the language through some innate capability In accord with recent data, it is possible to imagine children using their cognitive and vocal auditory processing skills on the historical product of Grammaticalization

Slide 73:The Origin of Language

And so we can hypothesize Human language originated from our adaptation to symbolic communication The grammatical structures of modern languages are due to the process of historic Grammaticalization and the analysis of that product using Imitation Schema formation Structural combining Done by separate individuals