18 and 24-month-olds use syntactic knowledge of functional categories for determining meaning and reference

Yarden Kedar

Marianella Casasola

Barbara Lust

Department of Human Development

Cornell University

Two word classes: Content Words and Function Words

• Function words (FW):– No descriptive content; serving a grammatical purpose

– Representing some basic functional categories (CP, DP, IP)

– Extremely frequent in language

– Have some typical prosodic and phonological characteristics

– Occur at the periphery of major phrases (‘the ball’)

– Have fixed distributional properties; particular FW occur in particular phrase types

The Acquisition of Functional Categories

Function words are typically omitted by young children

Are children insensitive to these elements?

The Acquisition of Functional Categories

(I) When do children start noticing FW?

(II) Can they distinguish between different FW?

(III)Do they use this knowledge to understand the

meaning or referents of sentences?

Evidence on children’s perception of function words

• Toddlers responded better to grammatical versus omitted-function-word utterances (Shipley, Smith, & Gleitman, 1969; Petretic & Tweney, 1977)

• Toddlers omitted English FW more frequently than nonsense FW in an imitation task (Gerken et al, 1990)

• Newborns categorically discriminated function and content words in a habituation-by-sucking design (Shi, Werker and Morgan, 1999)

Gerken & McIntosh (1993)

A comprehension/discrimination pointing task

• Show me the bird (grammatical)

• *Show me was bird(ungrammatical - English FW)

• *Show me gub bird (ungrammatical – nonsense FW)

• *Show me _ bird (ungrammatical - null)

Gerken & McIntosh (1993)Results:

Significant difference in correct pointing between the versus was, and between the versus gub

- but not between the grammatical condition (the) and the null condition

This Study – Questions

• The insignificant difference between

the grammatical and the null

conditions.

• Comparing the vs. and

• Younger children?

Design• 18- and 24-month-olds: Sixteen monolingual

toddlers in each age group

• [Can you see (FW) (Noun)?] e.g., Can you see and ball?

– Editing each segment (e.g., can you see) separately

• Eight different FW x Noun combinations; Two items of each FW type

The Preferential looking-listening paradigm

• Toddlers do not interact with the experimenter

• Choose between only two images

• Frame-by-frame offline coding

CUP

PHONE

BED

HAT

PLANE

TRUCK

CAR

SHOE

BALL

BOOK

BIRD

DOG

BRUSH

SPOON

DUCK

CAT

Dependent variables

First Look:• Was a toddler’s first look directed to the target

image?

Latency: • How long did it take toddlers to orient towards

the target image?

Proportion of Looking Time:• Duration of look to the target object during

control and test trials

Results: First Look to Target

First Look to Target

0.721

0.4920.548

0.667

0.0

0.2

0.4

0.6

0.8

THE AND EL NULL

Function Word

Mean

prop

ortio

n of

corre

ct fir

st loo

k

*the vs. and(p=.0002)

*the vs. el(p=.01)

Also, null vs. and(p=.03)

Main effect (only) for Function Word(p = .0073)

Results: Latency

• Main effect FW p = .014

• the < and p =.007

• the < el p =.004

• the < nullp =.024

LATENCY TO TARGET

0.374 0.992 1.035 0.8870.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

THE AND EL NULL

Function Word

Time (

sec)

*

Results: Immediate Latency(only cases in which first look was directed to target)

0.132 0.239 0.208 0.3440.0000.0500.1000.1500.2000.2500.3000.3500.4000.450

THE AND EL NULL

Function Word

Time (

sec) *

• Main effect FW p = .0001

• the < and p =.008

• the < el p =.026

• the < nullp =.024

Also: El < Null p=.036

Proportion of Looking Time (PLT):

• PLT to target: Difference from control to test trials

• PLT to target during test trials

PLT to target during test trials

0.6130.556 0.545 0.547

0.0

0.2

0.4

0.6

0.8

THE AND EL NULL

Function Word

Mea

n Pr

opor

tion

of

Look

ing

Tim

e

0.110

0.086 0.0890.082

0.000

0.020

0.040

0.060

0.080

0.100

0.120

THE AND EL NULL

Function Word

Diffe

renc

e in

PLT

Summary of Results

1. Replication of Gerken & McIntosh’s findings2. Extending G&M’s findings:

• Toddlers distinguished the grammatical condition (the) from the null condition

• Toddlers distinguished the determiner the from the conjunction and

3. 18-month-olds demonstrated the same patterns of looking behavior

Conclusions

• FW are detected and used to facilitate reference already at 18 months of age (preceding production)

• Computation of linguistic input is done at the phrasal/sentential level

• Specifically, Noun Phrases (or Determiner Phrases) have priority over simple lexical items for linking to semantics and determining reference:

– Such sensitivity could help children know the syntactic class of words/phrases even with no referential context

Future Research

• Younger age groups

• Comparing different FW pairs

• Comparative cross-linguistic research

• Developmental neuroscience: ERP

Thank You