How Children Learn the Meanings of Nouns and Verbs Tingting “Rachel” Chung Ph. D. Candidate in Developmental Psychology University of Pittsburgh

What’s in a word? beef /bif/ Noun (mass) Cow/ox meat Root Phonology Grammatical category Meaning Morphology

Why is word learning interesting?  Inductive problem - Potentially wide range of hypotheses  Mapping problem – Cross-linguistic variations  High growth rate

Why is word learning interesting?  Inductive problem - Potentially wide range of hypotheses  Mapping problem – Cross-linguistic variations  High growth rate

What’s a Gavagai?

Why is word learning interesting?  Inductive problem - Potentially wide range of hypotheses  Mapping problem – Cross-linguistic variations  High growth rate

Language may organize concepts in different ways  Melissa Bowerman Differences between English and Korean

English-speaking adults

Korean-speaking adults

English-learning 2-year-olds

Korean-learning 2-year-olds

Why is word learning interesting?  Inductive problem - Potentially wide range of hypotheses  Mapping problem – Cross-linguistic variations  High growth rate

Statistics  10,000 words by 1 st grade 5.5 per day from 1.5 to 6 yrs  40,000 words by 5 th grade 20.5 per day from 1 st to 5 th grade

Sources of information about word meaning  Principles and constraints  Pragmatics  Syntax

Principles and Constraints  The Whole Object Assumption  The Taxonomic Assumption  Mutual Exclusivity

Principles and Constraints  The Whole Object Assumption  The Taxonomic Assumption  Mutual Exclusivity

Whole Object Assumption in Initial Mappings Evidence Tendency of whole object interpretation in ambiguous situations with inappropriate syntax in languages without count/mass distinction More nouns in early vocabulary Novel nouns learned faster

Whole Object Assumption Criticisms Only roughly 40% of early words are object labels. Children learning Chinese, Japanese, and Korean learn verbs and nouns simultaneously

Whole Object Assumption Explanations Object concepts are richer and more cohesive Ostensive teaching of nouns more prevalent in middle-class Americans

Whole Object Assumption Consequences - speculations Verbs are harder to learn Adjectives are harder to learn e.g., color words (Soja, 1994)

Principles and Constraints  The Whole Object Assumption  The Taxonomic Assumption  Mutual Exclusivity

Taxonomic Assumption in Word Extensions Evidence Find another one Find another dog

Taxonomic Assumption in Word Extensions Basic Level (Perceptually based) Early categorization in infancy may be at superordinate level But most early words and extensions are basic-level.

Taxonomic Assumption in Word Extensions Conceptual extensions

Taxonomic Assumption in Word Extensions Shape Bias Find another dax

Principles and Constraints  The Whole Object Assumption  The Taxonomic Assumption  Mutual Exclusivity

Mutual Exclusivity Evidence Fast mapping of novel label to novel object when familiar object is present Lack of fast mapping of second labels

Mutual Exclusivity Value Fast-mapping Avoiding redundant hypotheses Overcoming whole object assumption Overriding taxonomic assumption

Nature of Principles and Constraints  Are they language specific?  How and when do children overcome them?  Are they applicable to learning of words in other classes?

Potential Principles and Constraints in Verb Learning  Whole Event Assumption?  Taxonomic Assumption?  Mutual Exclusivity?

Whole Event Assumption  Unlikely  Agentive manner/action  outcome > instrument > agent  Event parsing/representation is crucial

Taxonomic Assumption  What is event taxonomy?  Basic-level verbs?  WordNet (Miller & Felbaum, 1991)

Mutual exclusivity  Fast-mapping of verbs in 3-year-olds  Effect size is smaller

Role of Syntax General syntax-semantics links Tendency of object label interpretation with a noun and action interpretation with a verb (Brown 1957) BUT: How does the child know the grammatical category of a word?

Syntax and verb meanings Syntactic bootstrapping (Gleitman) Syntax narrows down possible hypothesis about verb meaning

He is daxing He is daxing it. He is daxing to her. He is daxing from her.

Naigles (1990)

Problems with syntactic bootstrapping research Infinite hypothesis space reduced by 15 times is still infinite Confound of semantics and syntax Requires syntactic knowledge

Role of Social and Pragmatic Cues Joint attention Referential intent Case of autism

Summary Multiple sources of information are needed in word mapping. Constraints are “default principles” that can be overridden given appropriate circumstances. Research should move beyond nouns.

Discussion questions Is there ordering of constraints? How are event nouns learned? (e.g., party, bath, trip) How are dual category words learned? Do nouns have to be learned before verbs are?