Download Corinne Stevens. P5577126 TMA05 Evaluate the arguments that

Corinne Stevens. P5577126
TMA05
Evaluate the arguments that challenge nativist theories of language development
In 1965 Noam Chomsky set the nativist perspective on language development by proposing
the existence of an innate Language Acquisition Device (LAD), whereby humans are born
with the pre-programmed ability to verbalize and comprehend all manner of sentences, even
if they have never been heard before. He argued that although language content is provided
by the environment, it is the principles of transformational grammar that are biologically
inherent, claiming that a domain specific, modular structure exists in the brain, thus allowing
children to “effortlessly” identify and utilize intricate language rules, to which he termed as
“Universal Grammar”. According to Chomsky (1981), “Universal Grammar” is visualized as
a “two-tier system”; a “hard-wired basic layer” equipped with “principles” significant to all
languages, and a “partially-wired” second layer containing “pre-set options” or switches,
reliant on for the setting of “parameters” (properties of a language), in order to distinguish
appropriate rules, relevant to the native language that the child is exposed to. He stated that
“Experience is required to set the switches. When they are set the system functions”
(Chomsky, 1986), and “a few changes in parameters yield typologically different languages”
(Chomsky, 1986), therefore acknowledging that the environment’s role is to help the infant
“set the switches”.
Nativists such as Fodor (1983) and Pinker (1994) advocated and elaborated on Chomsky’s
original viewpoint, adding their own interpretations regarding language development. Fodor
(1983) claimed that innate domain-specific, modular mechanisms exist in the brain to take on
specific tasks such as language. Pinker (1994) supports this in his belief that language must
arise from an innate mechanism in human brains, since it is far too complex to be learned,
maintaining that there is “an identifiable seat [for language] in the brain, and perhaps even a
special set of genes that help wire it into place” (Pinker, 1994). While nativists acknowledge
that the environment has a role to play in developing these mechanisms, they believe it is
over an evolutionary period that spans generations (Phylogenetic). It is the empiricist belief
however, that it is the environment that plays the major role in language development and this
takes place via interaction on an individual level (Ontogenetic).
Fodor’s “model of the mind” consists of three main mechanisms; a transducer, for receiving
external, sensory information; modular, cognitive input systems, for perceiving and
processing sensation before sending the information to a central processor which deals with
higher cognitive tasks (problem solving, abstract thought etc) by deciding how to utilize the
information. He states that it is the input systems that are genetically predetermined, modular,
encapsulated (working independently of other areas), domain specific regions that control
specific processing tasks (eg. Language), and it is his conception on “innately specified
modularity” has been of great interest to cognitive development theorists.
Karmiloff-Smith (1992), contested his theory on “innate modularity”, hypothesizing instead,
that the brain becomes “modularized” during the development process. Drawing on research
carried out by Neville (1991) and Johnson (1993) on “equipotentiality” (both left and right
hemispheres of the brain having “equal potential” for language development), KarmiloffSmith refers to the inherent property of plasticity that occurs during early brain development,
where other areas of the brain can take over a function if a specialized area becomes
damaged. Although language is associated with the left hemisphere of the brain in adults,
Reilly and colleagues (1998), who studied children with focal lesions, found that language
delay occurred regardless of which side of the brain the damage occurred. The most notable
delays in word knowledge occurred in the right hemisphere group, therefore suggesting that
the areas responsible for language acquisition in a child and are different to the region
controlling language processing in adults, in addition to exemplifying that other areas of the
brain can accomplish language if required. Karmiloff-Smith (1992) theorized that inherent,
domain-specified predispositions exist, which eventually select brain circuits for domainspecific tasks, resulting in the formation of modules; however, she states that development of
these modules occurs as a result of the brain “self-organising” due epigenetic activity (genetic
predispositions interacting with environmental input) rather than via innate modular
mechanisms proposed by Fodor. Johnson reinforces this view, stating “While regions of the
left temporal lobe may be best suited for language processing, they are not critical since
language can develop in a close to normal way without them. (Johnson, 1997).
A “self-organising” brain is a viable concept according to Connectionist, neural network
modelling. Plunkett & Marchman (1993) created neural networks to investigate language
acquisition, providing evidence on vocabulary spurt, morphological inaccuracy and U-shaped
development. They discovered that the consistent vocabulary spurts observed when
researching early language acquisition in infants could be demonstrated by computer models,
and their results demonstrated that learning became easier as a child’s vocabulary increased,
hence resulting in a sudden increase in vocabulary. Plunket & Marchman (1993) proposed
that a single mechanism was responsible for this, therefore giving support for empicist, single
route theories, and challenging dual route theories proposed in nativist explanations of
language development.
Pinker & Prince (1988) hypothesized that a dual route, or two innate, parallel cognitive
mechanisms are responsible for early language acquisition and mistakes occurring during the
process. According to them, the mechanisms encompass rule systems regulating the correct
word endings, and memory systems for learning inflections (words indicating past tense
verbs or plurals, eg. –ed, s). Their theory predicts that vocabulary inflections are reliant on
the memory system storing the required word and the rule system for providing the
appropriate, “regular” word ending. For example, if the correct irregular past tense verb
“threw” was already stored in the memory system, it would not be necessary to engage with
the rule system and it would be blocked. If, however, the word “threw” was not stored in the
memory system, the rule mechanism would be consulted, resulting in the application of the
regular verb ending (-ed), thus leading to the morphological error of “throw” being inflected
as “throwed”. Pinker & Prince (1988) argue that this over-regularization provides an
explanation for morphological errors occurring, in addition to presenting their view on why a
U-shaped pattern of development occurs during language production. Dual route theorists
explain this pattern by claiming that a child’s initial language production is perfect and that
the U-shaped dip transpires as more vocabulary is learned and more irregular verbs are
encountered, therefore leading to over-regularization since the child is relying on a regular
rule system that had accepted either “-ed” or “s” as default rules. The rise in the pattern
materializes as a result of the child experiencing and storing correct irregular inflections,
building up their memory system and minimising future errors.
According to nativists such as Pinker (1991), “double dissociation” which demonstrates a
failure in inflection usage provides evidence for dual route theory. Focusing on two
developmental disorders, Pinker (1991) argues that research has shown that children with
Williams Syndrome experience problems producing irregular, past tense verbs (Bellugi et al,
1990), while those with Specific Language Impairment (SLI) have difficulty producing
regular past tense verbs (Gopnik & Crago, 1991), therefore indicative of two systems being
required for inflection production. Conversely, Thomas et al (2001) observed no
discrepancies in regular/irregular past tense verb production in children with Williams
Syndrome and Bishop (1997) also discovered no clear-cut dissociation in SLI children,
therefore rendering Pinker’s evidence for dual route theory as questionable.
Dual route and Universal Grammar principles are contested by empirists such as Rumelhart
& McClelland (1987) who argue that all inflections are memorised within a single route
procedure. This theory gives consideration to huge memory capabilities, which opponents
allege is unfeasible; however, using connectionist models to support their claims, Rumelhart
& McClelland (1987) found that large numbers of inflections could be memorised by simple
neural networks. Also supporting this theory, Plunkett & Juola (1999) found that a trained
network of 5000 different inflections exhibited similar U-shaped development during training
to that found in children developing language. Results were also consistent with Brown’s
(1973) conclusions on children’s grammatical development, demonstrating that plural
inflections preceded past tense inflections. Single route theories claim that as more inflections
are stored to memory, over-regularization errors become more common. This is due to rising
competition between words for memory storage, resulting in “interference effects”, where
similar sounding words and their inflections easily present problems. For example, similar
sounding words such “man” and “fan” have different plural inflections; “fans” is regular and
“men” is irregular. If many regular words of similar phonologic structure are stored, irregular
words such as “man” may be over-regularized; however like dual route theory as more
irregular words are stored, less errors are made. Single route theory predicts that irregular
verbs of similar sound to regular verbs will be susceptible to having “-ed” added whereas
dual route theory states incorrect inflections are uninfluenced by similar words. Marchman
(1997) demonstrated in her investigation involving 74 children that an irregular verb (eg.
blow) with more regular verb “enemies” (eg. mow, show, stow) than irregular verb “friends”
(eg. throw, know) would be more vulnerable to having “-ed” added incorrectly and this is
consistent with single route theory. Further evidence favouring a single route explanation of
German inflectional morphology was illustrated in Szagun’s (2001) longitudinal study of 20
German children, where it was found that very young children made errors immediately when
using plural inflections, as predicted.
Nativist critic, Tomasello (2000) refers to the “piecemeal” nature in which infants build up
their grammatical knowledge when acquiring syntax, claiming that this is because they have
not yet learned what constitutes as “verbs” or “nouns”, fundamental to the nativist Universal
Grammar theory. Tomasello’s “distributional approach”, suggests that verb meanings play a
major role since they provide vital clues to rules regarding sentence structure. For example,
infants in Naigles (2000) preferential looking task that used transitive (needs object) and
intransitive (no object) verbs to examine whether meaning could be attached to grammatical
context found that they were able to link phrases to the images, therefore demonstrating that
their sensitivity to grammatical terms could enable them to learn about verb endings.
Tomasello argues that early categorisation of “verbs” and “nouns” are “emergent properties
of a learning process, rather than prerequisites for it” and that creativity in building sentences
arises from growing “pockets of knowledge” that stimulate each other, leading to “systematic
expression of grammatical regularities” His approach, however, offers no explanation for
how children overcome the over-generalization errors found in dative alternations (sentences
with different structures that have the same meaning) or question formation.
Using a neural network model trained to predict the next word in a sentence; Elman (1990,
1993) found that the computer was able to use the inbuilt features within sentence structures
to detect verbs and nouns and work out the correct sequence of those categories. He also
discovered that the computer’s ability to learn grammar was dependent on the sentence type it
was exposed to. He discovered that if it was exposed initially to simplified grammatical
sequences, it would perform better in learning more complex grammatical sequences later in
training. Some researchers refer to this simplified dialogue as “motherese” or “child directed
speech” (Snow, 1972) and argue that it teaches language that assists grammatical
development. (Furrow et al, 1979). Bruner (1975) argued that “true language” arose from
scaffolding a child’s learning using simplified speech to talk about objects. Despite
uncertainty regarding the motherese hypothesis, Elman’s experiment is congruent with it, as
it is with Tomasello’s “distributional approach”, therefore demonstrating that “grammatical
development proceeds in a piecemeal fashion”, in addition to demonstrating that interaction
is necessary for language development.
To conclude, this essay has attempted to focus on the viability of the empiricist challenge to
nativist theories on language development. Nativists argue that language is innate and
controlled by a domain specific, modular mechanism that is pre-programmed with
grammatical knowledge exclusive to any native language. Empiricists reason that cognitive
mechanisms develop as a result of direct interaction with the environment or via epigenetic
principles where brain is able to “self-organise” to correspond with environmental input.
Cortical lesion research has been inconclusive in finding a specialized area for language
acquisition in children; however research on “equipotentiality” using ERP scanning has
provided evidence for brain plasticity and Connectionist modelling has confirmed “selforganisation” does take place. Connectionist modelling has also provided substantial
information that favours empiricist, single-route and “distributional approach” theories,
whereas “double-disassociation” has not yet been conclusive for dual route theory. Some
aspects of nativist theory are conceivable and useful for understanding phenomena such as
language recognition; however, empiricist theories are reinforced by more convincing
evidence, with epigenetic research being the more rational approach to future language
development exploration.
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References:
First Relationships in John Oates, Psychological Development and Early Childhood, Oxford, Blackwell/ The
Open University.
Brain and Cognitive Development in Denis Mareschal, Mark H Johnson and Andrew Grayson, Cognitive and
Language Development in Children, Oxford, Blackwell/ The Open University
Reading A: “The fragmented mind” from what infants know in Jacques Mehler and Emmanuel Dupoux,
Cognitive and Language Development in Children, Oxford, Blackwell/ The Open University
Reading B: Beyond Modularity in Annette Karmiloff-Smith, Cognitive and Language Development in Children,
Oxford, Blackwell/ The Open University
The development of children’s understanding of grammar in Kim Plunkett and Clare Wood, Cognitive and
Language Development in Children, Oxford, Blackwell/ The Open University
Reading A: An extract from The Articulate Mammal in Jean Aitchison, Cognitive and Language Development
in Children, Oxford, Blackwell/ The Open University
Neural Networks Study Booklet, ED209 Child Development, The Open University