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

Subjects 24-month-olds: 16 (9 females, 7 males) monolingual toddlers Age range: Mean = 24;01 Mean MLU (in morphemes) = 1.09 Use of FW in obligatory contexts = 22.83% (0%-60%) 18-month-olds: 16 (females, males) monolingual toddlers Age range: Mean = 17;25 Mean MLU (in morphemes) = 0.43 No use of FW

The Preferential looking-listening paradigm Toddlers do not interact with the experimenter Choose between only two images Frame-by-frame offline coding

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

Predictions In grammatical test trials: 1.Significantly more identifications of the target image on first look 2.Significantly shorter latencies to the target image 3.Overall greater proportion of looking time to the target image

Results: First Look to Target *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: First Look to Target

Results: Latency Main effect FW p =.014 the < and p =.007 the < el p =.004 the < null p =.024

Results: Latency

Results: Immediate Latency (only cases in which first look was directed to target) Main effect FW p =.0001 the < and p =.008 the < el p =.026 the < null p =.024 Also: El < Null p=.036

Results: Immediate Latency

Proportion of Looking Time (PLT): PLT to target: Difference from control to test trials PLT to target during test trials

Summary of Results 1.Replication of Gerken & McIntosh’s findings 2.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

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