Transcript The Generative approach

The acquisition of grammar
(syntax and morphology)
Chomsky, Wexler, Pinker
THE NATIVIST APPROACH
Poverty of the stimulus
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Who saw what?
Who gave a gift to whom?
Who went where?
*?Who went when?
*Who went why?
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It is likely that John will be delayed.
John is likely to be delayed.
It is probable that John will be delayed.
*John is probable to be delayed.
Abstract knowledge
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Who did John wonder you gave a ring to _ ?
*Who did John wonder what you gave _ to _ ?
*Harryi admires himi.
Harryi admires himselfi.
Tom*i believes that Harryi admires himselfi.
The nativist conclusion
(Chomsky, Pinker)
• The logical problem of language acquisition
– Analogical learning leads to overgeneralisation
errors
– To recover from these errors, negative evidence
would be needed (explicit information that certain
sentences are ungrammatical)
– the solution is to assume that children are
equipped with innate knowledge of language
The “continuity” hypothesis
• Humans are born with a Language Acquisition
Device, containing Universal Grammar.
• Substantive universals
– parts of speech: noun, verb, adj, adposition,
conjunction …
– grammatical functions/relations: subject, object,
predicate, complement, adjunct …
– syntactic devices: case, agreement, tense, number …
The “continuity” hypothesis
• Rules operating over the substantive universals
(structure building and constraints)
– generative grammar: a finite set of rules operating
over a finite set of substantive universals allowing an
infinite number of sentences (recursion)
• Parameters allowing diversity
– pro-drop, head-dependent order
• A mental lexicon containing words,
subcategorisation frames (argument structure)
and other idiosyncratic properties
The process of language acquisition
• Category labelling (linking): assigning
substantive universal classes to words/phrases
in the target language
• Setting parameters
Pro-drop parameter
Pro-drop
• Kati alszik.
Kate sleeps
• _ alszik.
sleeps
• Az eső esik.
the rain rains
• _ esik.
rains
Non-pro-drop
• Kate is sleeping.
• She is sleeping.
• It is raining.
• It is raining.
Head Direction Parameter
Right-branching (head-first)
• Verb – object
• Noun – adjective
• Preposition – noun
• E.g. Spanish
Left-branching (head-final)
• Object – verb
• Adjective – noun
• Noun – postposition
• E.g. Japanese
McWhinney, Goldberg, Tomasello
USAGE-BASED APPROACHES
Critique of nativism
• Languages are too diverse for a Universal
Grammar (Croft, Goldberg)
• UG does not solve the problem of category
labelling or the acquisition of the lexicon
(Pinker, McWhinney)
• Children do overgeneralise, UG does not have
an answer to how they recover from the
errors (Bowerman)
Assumptions
• The child’s initial knowledge of language is
qualitatively different from the mature state
(non-continuity)
• The learning mechanisms are not domain-specific
• social cognition
• pattern-finding, statistical learning
• Construction grammar:
– not lexical items + syntactic rules
– but constructions, patterns with specific functions
From signal to structure
• Phonological (prosodic) bootstrapping
– prosodic cues (pitch, pauses) help identify phrase
and clause boundaries (Morgan & Demuth 1996)
– even newborns can distinguish content words
from function words based on phonological
features (Shi et al 1999)
From signal to structure
• Distributional cues
– categorisation based on co-occurrence patterns: articles,
prepositions, morphological markers, etc. (Maratsos 1990)
– school-age children learn an artificial language containing
such information faster (Saffran 2002)
– 1 year olds can categorise words based on distributional
information (Gomez & Lakusta 2004)
• training phase: listening to aX and bY phrases (a and b: one
syllable, X and Y two syllables)
• testing phase: light flashing on one side, when child looked,
training language or a different language was played. Looking time
was measured. Significant difference.
– 18 months olds can learn long-distance agreement in an
artificial language: pel-wadim-rud, pel-kicey-rud, pel-puserrud (Gomez 2002) – type frequency is important: number
of different items shown in the pattern
Generalising patterns (abstraction)
• 7 months olds can learn patterns based on
examples (Marcus et al 1999)
– trained on ABB language
– tested on ABB vs. ABA
PRAGMATICS
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expressing and identifying intentions
using speech acts
recovering implicatures
conversational norms
non-literal language
discourse coherence
New vs. given information
• perspective taking, establishing common
ground (at 3-4 years)
– Referential communication task
• 4-12 year olds show egocentric behaviour (disregarding
the other person’s perspective) (Epley et al 2004)
• in a simpler set-up, six year olds displayed sensitivity to
the other person’s perspective (Nadig & Sedivy 2002)
Array of objects, including both occluded and mutually observable objects,
from the participant’s and director’s perspective. (The critical
instruction from the director on this trial was to ‘‘move the small truck above
the glue.’’) Epley et al 2004
Non-literal language and ToM
• Metaphor, irony, humour (Glucksberg, Gibbs)
• Implicatures (Grice, Sperber & Wilson)
Grice’s implicatures
• I’ve put the key in either the green or the
round box.
Those with either rich or famous parents can
come in.
• Charles fell and broke his leg.
It’ll rain and there’ll be a strong wind.
• If it rains tomorrow, we’ll stay in.
• I’ve had some biscuits.
Grice’s maxims
• Maxim of quantity
– Scalar implicatures
• Maxim of quality (truthfulness)
– Irony, metaphor
• Maxim of relation (relevance)
– metaphor
• Maxim of manner (clarity)
Scalar implicatures
• Maxim of Quantity
– some -> not all (Katsos & Bishop
2011)
– 2 -> not 3
– may -> not must
• “You need to throw three rings
on the stick to win.”
Development
• Metaphor:
– depends on novelty
– Simple metaphors understood by 4-5 years
• Irony
– Often taken to be deception
– Recognised from about 7-8 years
• Scalar implicatures
– Logical meaning preferred (if given a binary scale)
– Adult performance from about 8-9 years
Possible reasons for delayed
acquisition
• Strong correlation with (?)
– ToM performance (Happé)
(to understand intentions abstracting away from
literal meaning)
– Vocabulary and grammar ability (Norbury)
– Cognitive flexibility (Foppolo)
(to maintain two or more meanings and switch
between them as required by the situation)