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
1
Evidence for Item Based Development

Introduction

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What is item-based development?
Studies in Lexically Based Grammar
Studies in Item Based Development
Conclusion
2
Introduction

What is Item Based Development?


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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
3
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
a dog
The house
a plate
The …
a…
4
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…)
5
Introduction

Transitive and Intransitive

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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
6
Introduction



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

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
7
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
8
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 (λεξικόν) meaning vocabulary
9
First Debate

Grammar from the Lexicon
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What does this mean?
Grammar has vocabulary qualities
Grammar and vocabulary are learned the same
Same mental mechanisms used for both
Chomsky

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Grammar cannot be learned! (in finite time)
It is different from vocabulary
10
Nature of Debate
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Epistemology
Empiricism Vs. Nativism

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Plato Vs. Aristotle
Do we have a special grammar organ, or are
we just really smart?

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Really smart = innate abilities not specific to language
Soft empiricist claim
11
Emergentism

Emergentism

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Solutions to a problem are unpredictable
We will explore the Emergentist approach

Emphasizing the union between grammar and lexicon
12
The Giraffe


Is the giraffe’s neck a “leaf eating organ”?
Is the giraffe itself a leaf eating organ?
13
Humans and Giraffes

Hypotheses: Human grammar has evolved
like the giraffe’s neck

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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
14
Evidence

Two types of evidence

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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
15
Evidence for Item Based Development


Introduction
Studies in Lexically Based Grammar
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Normal Children
Atypical Populations
Lexicon and Grammar in the Adult Brain
Studies in Item Based Development
Conclusion
16
Studies

Research in normal children

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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
17
Studies

Grammar and lexicon in the adult brain


Does modularization occur in a later stage?
We will examine neurological patients
18
Development in Normal Children

General Maturation of speech development (English)
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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
19
Grammar, Comprehension Production


Zones of acceleration for each domain are separated by
many weeks
Lets try and find a connection
20
Vocabulary and MLU

Correlation between vocabulary and MLU


Best indication for 28 month MLU is 20 month vocabulary
Correlation is not cause
21
Cross Sectional Grammar Complexity

Individual differences around the grammar on vocabulary
function are rather small (small s.d.)
22
Grammar and Expressive Vocabulary


Tight correlation between grammar and vocabulary
Clear dissociation between words comprehended and
words produced
23
Grammar and Expressive Vocabulary

Fan shaped pattern

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
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
24
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
25
Longitudinal Study

We can see that the link between grammar and lexical
development extends to longitudinal studies as well
26
Explaining the Link

Perceptual bootstrapping


Logical bootstrapping


Grammatical function words are short, low in stress and
difficult to perceive
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
27
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
28
Development in Atypical Populations


We would like to find a pediatric population
which displays a dissociation between
grammar and the lexicon
We shall examine
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Late and early talkers
Early focal lesions
Williams Syndrome and Down Syndrome
Specific Language Impairment (SLI)
29
Late and Early Talkers
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Late talkers

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Early talkers
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Children of age 18 to 24 months who are in the bottom
10th percentile for expressive vocabulary
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?
30
Late and Early Talkers


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Grammar-on-vocabulary function for two children
Age 16 to 30 months
Age is a poor predictor of vocabulary and grammar
31
Two Case Studies
32
Two Case Studies

MW
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SW
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17 months old, expressive vocabulary 596 words, MLU 2.13
21 months old, expressive vocabulary 627 words, MLU 1.12
Deductions

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
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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
33
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)
34
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
35
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
36
Early Focal Lesions

Absence of left right differences
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Wernicke’s area

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Absence of global differences
Small but reliable disadvantage in word comprehension for right
focal damage
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
37
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)
38
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 14 children in the outskirts
39
Williams Vs. Down

Williams (WMS) and Down (DNS) syndromes

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Down
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Both constitute a form of genetically based mental
retardation
Mean IQ’s between 40 and 60
Contrast in grammar development
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
40
Williams Vs. Down

When do groups separate?


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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?
41
Williams Vs. Down
42
Specific Language Impairment


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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
43
Grammar and Lexicon in the Adult Brain

Conclusions at this point

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Adult neural mechanisms

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We’ve seen an interdependence between grammar and
lexicon
compatible with unified grammar/lexical approach
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)
44
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
45
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
46
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).
47
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
48
All Aphasic Patients have Lexical Difficulties

Anomia

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Deficit in word retrieval
All Aphasic patients have some sort of
Anomia

Hence, a grammar deficit is always accompanied by a
lexical deficit
49
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
50
Expressive Agrammatism
51
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
52
Receptive Agrammatism

Receptive agrammatism


Is characterized by a difficulty of processing inflections
and closed-class words. More difficulties with noncanonical 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)
53
Receptive Agrammatism

Not unique to aphasia populations, present in normals
under adverse conditions
54
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
55
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?”
56
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
57
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
58
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
59
Additional Attempts

Key to Graph
60
Additional Attempts

As we can see, creativity improves with age
61
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
62
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
63
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
64
Usage Based Model

Nativist model is lacking



Usage Based Model




At odds with empirical data
A new model is needed
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

This resembles the lexically based grammar we spoke of earlier
resources
65
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
66
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
67
Evidence for Item Based Development




Introduction
Studies in Lexically Based Grammar
Studies in Item Based Development
Conclusion


Grammaticalization
Lexically based grammar
68
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
69
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
70
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”
71
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
72
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
73
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Evidence for Item Based Development