Lecture 5 Developmental Psychology PDF

Early Multi-Word Speech: Nativist Approaches Professor Anna Theakston PSYC21021: Topics in Developmental Psychology Overview Last week, focus on how constructivist approaches explain acquisition of multiword utterances. This week, nativist (or generativist) accounts Learn...

Early Multi-Word Speech: Nativist Approaches Professor Anna Theakston PSYC21021: Topics in Developmental Psychology Overview Last week, focus on how constructivist approaches explain acquisition of multiword utterances. This week, nativist (or generativist) accounts Learning Objectives By the end of this week you should be able to: Outline some of the assumptions of nativist accounts of language acquisition Outline the assumptions of 'maturation' accounts of language acquisition Explain what is meant by 'the linking problem' and describe one account put forward to solve the problem Evaluate the strengths and weaknesses of nativist approaches Lecture Structure Part A: Background Part B: Nativist approaches – assumptions & Principles & Parameters Part C: Maturational models Part D: The linking problem Overall summary & areas for evaluation  Do I have Universal Grammar? Part A: Background !? In contrast to Constructivist Approaches, Nativist (or generativist) approaches assume that children approach the task of learning language with innate machinery that is specific to language, sometimes described as a Language Acquisition Device or Universal Grammar (UG). the world any language ↳ of Steven Pinker on How Children Learn Language As you watch the video, listen out for the evidence that is cited in support of a Universal Grammar account from the · kids use language rules & to generalisations moment they begin speak. ·" sentence that is made up by the adult, a gone sticky" that is not All this shows kids make up theirown sentences. Did you notice any similarities with last week? The theory you adopt can influence how you interpret the available empirical evidence. It is important to try to look at the evidence objectively and weigh up which theoretical account provides the best fit. children are pre-wived with universal grammar. Chomsky : a Nativists argue that children's utterances are creative because they have access to innate grammatical rules; Constructivists argue that children's utterances are creative because creativity is based on the use of lexical frames learned from the language children hear, with new items inserted into variable 'X' slots, e.g. I want X  ea that the todoe we they believe have owitactors > - Nativists argue that children observe adult word order because they have an abstract rule trat Subject – Verb - Object -theybelievefacanildrenearning. , Constructivists argue that children observe adult word order because they pick up highly frequency lexical frames from their input (which, of course, follow the adult word order) I – want – a drink  1 wug, 2 wugs… Nativists argue that generalisations (e.g. adding inflections to words, wug -> wugs) provide evidence of-abstract (innate) rules Constructivists argue that generalisations demonstrate that children learn these patterns gradually from distributional analysis of the language they hear - Part B: Nativist approaches - assumptions & initial evidence 1. What are nativist approaches to language acquisition? 2. Principles & Parameters (P&P) 3. Evidence to support P&P approaches 4. Challenges for P&P approaches  has been born with a abstracr(innat child - a rules in their used to learn be language. 1. Nativist assumptions  Assume that grammar is a symbolic computational system which processes the relationships between abstract variables (e.g. Chomsky, 1995; Marcus, 1998).  Assume that grammatical categories and rules are given apriori in the child’s brain from birth (UG). grammar. ↳ universal  Predict that the acquisition of a particular aspect of grammar should have an all-or-nothing quality. ‘As soon as an item is assimilated into a class, that item automatically inherits the privileges of that category.’ (Marcus,1998: 250) work out that 4) For example, as soon as you belongs to the noun it 'at' is a nown should be able to , use category and then the youwordat in thesame waa General predictions Radford (1990: 61): ‘...Once a child is able to parse an utterance such as "close the door!", he will be able to infer from the fact that the verb "close" in English precedes its complement "the door", that all verbs in English precede their complements…’ Prediction 1: children should learn these innately specified aspects of grammar very early on Prediction 2: children should show consistent treatment of members of a particular grammatical category.  2. The nature of UG: Principles and Parameters O All the possible rules for languages are innate. Grammar is universal (UG) – the rules of grammar apply in all languages. Where the rules of grammar differ across languages, they do so in highly constrained ways which are encoded by parameters. & you need There are different settings for each parameter is the to work out what right Children need to work out which parameter settings apply setting. for the language they are learning. Examples of parameter settings Word order – Verb-Object (English) or Object- Verb (Japanese) I eat sashimi “watashi-wa sashimi-o tabe-tai-desu“ = I sashimi eat-want Subject use – In some languages subjects are obligatory (English), in others subjects are optional (Italian). It is raining Sta piovendo = is raining 3. Theoretical advantages of UG Avoids problem of explaining how children acquire complex grammatical rules Allows a unified theory of acquisition across languages whilst explaining how languages differ.  Empirical Evidence for Principles & Parameters Children’s early utterances (usually) observe adult word order – taken as evidence the relevant parameter is set. Children are productive from early on (allgone sticky) – taken as evidence they are applying rules of grammar. Some evidence that children understand the role of word order (Subject-Verb-Object transitive construction) from age 2yrs or earlier from preferential looking studies… subietverb-objec a b hey · arenot good at using  Preferential looking/pointing studies things e different - Check which screen child points at First give a sentence & then check which matches pic child pointing “The frog is kradding the monkey” ( - monkey. The frog is doing something to the Subject comes before in English. “The monkey is gorping the frog” ~ action. The monkey doing is subject comes before-  Preferential looking & pointing studies Children aged 1;9 can identify the correct picture to match Subject-Verb-Object sentences from a choice of 2 causal actions (Gertner, Fisher, & Eisengart, 2006) Taken as evidence for setting the word order parameter brain. - its already in their BUT - disagreement from constructivists as to what these F results mean – comprehension vs. production Constructivists believe that it may be a case where is believe that whatever word children may just are is the subject & that's why they said first. the pointing right getting have not learned enough to be able Children may put sentences together. to 4. Theoretical problems for UG Parameters not clearly specified. How many parameters are there? Which aspects of language are coded by parameters and which are not? Unclear how children avoid setting parameters incorrectly. Want a drink?, Got to go now Bilingualism – how do children set two (or more) versions of same parameters? Empirical evidence against P&P -subject-verb-object Children display limited knowledge of SVO word order in production and act-out studies (e.g. Akhtar et al, 1997; Akhtar, 1999; Matthews et al, 2005; Chan et al, 2010). rules based X around but Naturalistic data studies provide evidence of partial, some not lexically specific knowledge within a grammatical category words all. – verbs, auxiliaries, determiners (e.g. Pine et al, 1998; Lieven et al, 1997; Wilson, 2003) Many studies show a very close relation between what children hear, how often, and what and when they learn Glanguage (e.g. Ambridge et al., 2015) from caregivers Interim summary Nativist approaches provide an account of children’s early multiword utterances that emphasises their similarity to a childrenfadt adult language between no difference > - Continuity accounts (that posit grammatical rules from the outset) explain development in terms of limitations on performance rather than limited knowledge Next: maturation accounts to explain why children’s language develops, while maintaining innate knowledge Part C: Maturational models Children's language develops (changes over time), so many researchers argue that this provides evidence that they do not start out with a full innate UG (contra continuity accounts). One solution to this problem is to build in a part of UG that matures over time according to a biologically-determined timescale. (e.g. Radford, 1990) Radford’s (1990) maturational model At the Lexical Stage of development (around 20 months), children's utterances consist of mainly content words such as nouns, verbs, adjectives and prepositions, with other parts of the corresponding adult utterance omitted. At the Functional Stage (around 24 months) the child's innate grammar 'matures' and the parts governing the use of more complex grammatical components switch on; for instance auxiliary verbs (e.g. to mark modality, certainty, futurity - can, will, might), determiners (to distinguish definite and indefinite referents - a/the), and inflections (to mark tense and agreement - watch/watch- ed, I watch/He watch-es) comonte Distinct stages of development? Lexical utterances ↑ Functional utterances a cons Kathryn no like celery I’m pulling this Hair wet I don’t need that Pig say oink Will you help me? Mummy doing? She likes icecream I watched the ducks Hands dirty Theoretical Advantages & Evidence Explains why early utterances are not fully grammatical. Allows for development over time so more likely to fit the empirical data. Some have claimed a similar trajectory of learning for typically developing children with normal hearing, deaf, blind (e.g. Gleitman, 1981), despite their experiences of the world being different. Theoretical & Empirical Problems Difficult to identify precise point in development when maturing aspects of the grammatical system come ‘on-line’. From earliest stages children show some use of most grammatical functions, although inconsistent, and varies across languages At around 24 months, children’s use of many ‘functional’ words related to lexical frames Can I X?, Don’t X etc. (Lieven et al, 1997) Interim Summary UG approaches claim innate abstract grammar, but explain changes in children’s language over development in terms of biological maturation of parts of the grammatical system. BUT Do changes in language over development actually reflect a process of gradual learning from the input combined with the ability to be productive in limited ways? (constructivist account) How can we distinguish these two approaches? Part D: The linking problem 1. What is the Linking problem? 2. A solution - Semantic Bootstrapping 3. Advantages & disadvantages 1. What is the This is a dog, by the way, dog is linking problem a noun! How do children link up their innate knowledge of grammatical categories to the words they are hearing? Caregivers don’t label particular words as nouns, verbs etc. But Universal Grammar – what children are hypothesised to have innately - is defined in these terms  2. A proposed solution – Semantic Bootstrapping (Pinker, 1984; 1989) Assumes: Grammatical (syntactic) categories and rules innate Children use semantics (meaning) to map words in the input onto these innate syntactic categories by using innate Linking Rules to map semantics onto syntax Relations between grammatical categories & meaning? Dog You Noun Kick Verb verb Bite Verb Car Noun noun noun Tree Noun verb Chase Verb Linking rules between meaning and syntax The child ‘links’ individual words to innate grammatical categories (e.g. noun, verb, adjective, preposition, …)…. Word meaning Child assumes that the word is a …. Attribute Adjective Person, thing Noun Action, change of state Verb Spatial relation, path, Preposition direction, Linking rules cont. The child can also link semantic roles: Agent – the person carrying out the action Patient – the person or thing affected by the action to syntactic roles Agent = Subject of sentence Patient = Object of sentence  How does linking work? IMAGINE YOU HEAR: “wug tamo pim” 1) ‘Wug’ means ‘dinosaur’ 2) ‘Pim’ means ‘puppet’ 3) The agent in this picture/event is the puppet (‘Pim’) 4) So the puppet is the Subject 5) So the Subject comes after the Image showing puppet Object in this language – dragging a toy dinosaur Object-Verb-Subject word order along comes at the end for · figured out that the subject this specific sentence · Grammatical categories Want verb Verb noun Idea Noun verb Think Verb See verb Verb noun Problem Noun Pain verb Noun The problem – it’s not always easy to work out grammatical categories from meaning… Not all verbs are actions (Believe, want, need) Not all nouns are concrete objects (Idea, dream, justice) Not all subjects are agents (She wants a drink) Solution: Use a form of distributional analysis to determine word order for the language from prototypical sentences. Then apply knowledge of word order to work out grammatical category of more abstract terms.  Using a prototypical sentence to work out word order and grammatical categories for non-prototypical examples Prototypical transitive sentence The cat [Agent=Noun=Subject] Transitive chased [Action=Verb] sentence the mouse [Patient=Noun=Object] Noun phrase Verb phrase Subject Noun phrase Verb Object The cat chased (agent) (action) the mouse (patient) I want a drink 3. Advantages of semantic bootstrapping Explains how children break into innate system. Explains why early utterances follow adult word order. Explains how children learn verbs which are not actions, nouns which are not objects etc. 4. Problems for semantic bootstrapping Many of children’s early lexically-specific utterances are not semantically prototypical, and therefore are unlikely to be based on innate knowledge of semantic linking rules there isn't - obvious agent an. I want a drink, I don’t like it (Lieven et al, 1997) - In passive sentences, the noun phrase (NP) which is usually the object of an active transitive becomes the subject ACTIVE: =agent > patient- The cat (agent:Subj) chased the mouse (patient:Obj) PASSIVE: patient > agent = - The mouse (patient:Subj) was chased by the cat (agent:Obj) The problem of passives If the child hears passive utterances (e.g. the postman was bitten by the dog) early on, she may use semantic bootstrapping to conclude that her language is object- verb-subject problems parsing other utterances Some nativists propose that the passive ‘Parameter’ doesn’t mature until later (5yrs) so passives are learned late (e.g. Borer & Wexler, 1987) But, Children do hear and use passive sentences from fairly early on, (e.g. in Tomasello’s verb island study), especially in some other languages (e.g. Demuth, 1989). Interim summary Nativist approaches claim an innate abstract UG. But how do children map words onto grammatical categories? Semantic Bootstrapping proposed as a solution based on children’s perceptual understanding of the world around them and innate linking rules But the approach faces problems in terms of fit to the empirical evidence from children’s early utterances  Overall Summary Nativist account introduced to explain how children learn how to put words together into sentences. Assumes children operate with innate knowledge specific to grammar. To account for differences between languages, grammar encoded in Principles and Parameters. Continuity accounts assume children start out with full grammatical knowledge Maturational accounts assume parts of the grammatical system 'switch on' at different stages in development based on a predetermined biological timetable. Key challenge - how do children link up the language they hear with their innate grammar; the Linking Problem. Critical Evaluation Children show improved performance on comprehension tasks compared to production – does this demonstrate that they have innate abstract knowledge? How can we differentiate between maturation of innate grammar and development due to gradual learning? And for those of you interested in neuroscience, how might innate grammar be represented in the brain?  Reading Guidance The material covered in this lecture will be assessed via a short answer & MCQ Exam. Note, questions may require you to reason about and make inferences from the information you have learned. Students who have a better understanding of the material are better able to manipulate the information to arrive at the correct answers. You might find it helpful to read sections from: Clark, E. (2009/2016). First Language Acquisition. The 2nd Edition is available as an electronic VLeBook via the Library website that you can download or read online, and is suitable for this course unit. The updated 3rd Edition is available in hard copy from the library. For this lecture content, the following section is most helpful: Part IV (Process in acquisition), Chapter 15 (Specialization for language), pp. 369-374