STRUCTURAL LIMITS ON VERB MAPPING The role of abstract structure in 2.5 year olds’ interpretations of novels verbs Article by : Cynthia Fisher,University of Illinois, 2002 Presentation by : Denise, Shauna, Kara, Rachelle, Mélanie & Robyn

Let’s set things up a little... Background, terminology & previous studies…

n Everyday, without noticing, adults take for granted that there is a link between syntax and meaning. n The structure of an utterance affects its interpretation. –Example: The cat ate the mouse. The mouse ate the cat.

WHY? Bootstrapping! n The syntactic bootstrapping theory… n The idea that children use information about the sentence structure to guide sentence comprehension from an early point in acquisition. n In other words… semantics builds on top of syntax.

Many support this claim... n Children between the approx. ages of 2 and 5 take novel verbs in different sentence structures to have difference meanings. n Naigles & Fisher

NAIGLES Results n Children who heard TRANSITIVE: –LOOKED longer at the causal scene The duck is blicking the bunny. n Children who heard INTRANSTIVE: –LOOKED longer at the non-causal scene The duck and the bunny are blicking.

FISHER 1996 n Same experiment but they HID THE IDENTITY WITH AMBIGOUS PRONOUNS n Assessed the interpretation by asking questions about whose role the verb described. –Intransitive: Which one pilked the other one fast? –Transitive Which one pilked fast?

Results for both experiments… n Children and adults are more likely to choose causal agents as the subject of the transitive sentences. n This result is evidence that the structure of the sentence and the arguments was meaningful to the children (Fisher)

FISHER - Main Ideas... n Syntactic Bootstrapping n Abstract Representation n Predictions: –Even though children are conservative with new verbs, syntactic bootstrapping will still play a role for children under the 3 years old.

SOME DISAGREE… n Abstract representation plays a minimal role in the early phases of acquisition n Based on these findings… –Children are quite conservative –Children produce late errors The late errors are followed by a period when the child combines verbs and sentences only in patterns that are present in the input.

Fisher’s Response... n A big part of syntax acquisition must be completed before productive innovation is possible n Considerations: –Children need to figure out the grammatical functions –Innovation requires that the child to have a language reproductive mechanism allowing him to retrieve or build sentence structure only on meaning.

FISHER - Let’s recap... n year old children are similar to adults in regards to their production of novel verbs. n They have a set of fundamental syntactic structures (abstract representations) n They use the syntax to interpret new utterances.

THIS STUDY HYPOTHESIS

HYPOTHESIS… n Do 2.5-year-olds use overall sentence structure to help them interpret novel verbs?

EXPERIMENT

EXPERIMENT 1- Subjects n yr. olds –12 girls –12 boys n 23 3 yr. olds –12 girls –11 boys n 24 college-aged adults –12 female –12 male

EXPERIMENT 1- Subjects n Children and adults randomly assigned either transitive or intransitive condition and to one of two stimulus orders. n Showed 4 brief videotaped caused-motion events. (approx sec). n One active participant (agent) directly caused the motion of passive participant (patient) n Each videotaped event shown 3 times in row separated by brief intervals of blank screen.

Sentence Structure n The two sentence contexts differed in the number of noun-phrase agreements n Sentences provided only structural information about verb by using only ‘she & ‘her to identify participants n There were no direct clues as to the identity of the subject or object of verb n Nonsense verbs were heard during the “ blank screen” interval: –preceding first repetition of event –repeated 9 times during –between 3 repetitions of each event.

Table 1 - Stimulus events and sentences She stipes (her) over there! She braffs (her) over there! She pilks (her) back and forth! She gishes (her) around! Stimulus sentences Participant A pulls B backwards along a slippery surface by pulling on B’s backpack. A rolls B toward her on a wheeled dolly by pulling on a feather boa tied around B’s feet. A wheels B forward and back in a red wagon. A rotates B on a swivel stool by pulling on the ends of a scarf around B’s waist. Unfamiliar motion events

She stipes (her) over there!

She braffs (her) over there!

She pilks (her) back and forth!

She gishes (her) around!

n Depending on which condition the child was assigned to the experimenter asked either: “Which one (verb)ed the other…? Point!” (TRANSITIVE CONDITION) OR “Which one (verb)ed…? Point!” (INTRANSITIVE CONDITION) n This experiment was also run with adults

EXPERIMENT 2 n An additional 24 two and a half year olds were tested. n Same procedure was used.

RESULTS

Hypothesis confirmed n Children interpret new verbs in accord with their number of arguments. n When interpreting new verbs describing the same motion events, children who heard Transitive sentences were more likely to assume that the verb referred to the actions of the causal agent.

n Both children and adults who heard the Transitive sentences were more likely to point to the agent of each causal event n These results suggest that children use syntax to guide interpretation of novel verbs.

Table 2: Mean proportion agent choices by age and sentence context, Experiment 1 n Age groupIntransitiveTransitiveMean n 30 months0.326 (0.110)0.625 (0.104) (0.080) n 40 months0.045 (0.045)0.667 (0.089)0.370 (0.083) n Adults0.313 (0.088)1.00 (0.000)0.656 (0.084) n Mean (0.054)0.64 (0.053)

DISCUSSION

n The study supports previous experiments showing children are sensitive to structure in interpretation n Extends data to younger children

IF... n The syntax-semantics link is present so early in life n Children use sentence structure to interpret new verbs at such an early age… n WHY ARE THEY UNWILLING TO INNOVATE WITH NEWLY-LEARNED VERBS???

n the requirements for interpretation of words are very different from those for innovation n in order to innovate, children need: –to know the syntax of the language (including morphology and word order) –to develop a system that will produce sentences with these regularities, without the help of having practiced a specific structure

Let’s look at another reason that children are conservative... n Imagine child sees toy Ernie launched through the air

n Child hears –“Ernie pilked!” –(Possible translation: “Ernie flew/soared/fell”) n In this case, verb is used intransitively n How is child to know if the verb can also be used transitively?

Assumptions of the structure- mapping view: n The data obtained in this experiment imply that early sentence comprehension is facilitated by abstract mental representations of sentence structure –What is the nature of these abstract representations? –How do these representations influence early verb development?

n Researchers continue to investigate the structure-mapping mechanism for early syntactic bootstrapping because: –It makes sense given widely held views about language acquisition (Fisher, 1996, 2000a; Fisher et al., 1994) –It makes unique and verifiable predictions of verb interpretation errors

The structure-mapping mechanism assumes that: n Semantic structures of verbs match up to conceptual knowledge of events n Children can identify and understand some nouns in fluent speech

These assumptions have consequences for early sentence comprehension... n Structural alignment allows children to obtain a fairly accurate semantic structure for the sentence n Structural alignment puts constraints on sentence interpretation n Because they can already link nouns with referents, children should not have trouble comparing structural alignment of sentence structures with relevant conceptual structures

Structure-mapping and cross- linguistic variation: n Structure-mapping is abstract enough to allow for cross-linguistic variation in the relationship between a language’s syntax and its semantics while still providing necessary constraints on these links n Structure-mapping takes variation into account because it assumes an incomplete knowledge of sentence structure on the part of the infant

Predictions of Structural Alignment: n Fisher’s proposed structure-mapping mechanism for syntactic bootstrapping uniquely predicts that nouns in a sentence are not the same as the arguments of a verb

Future research of this nature will: n Test in detail the predictions of early partial- structure matching in sentence comprehension n Help us obtain a better understanding of which information sources, constraints, and biases children use in language acquisition

Future Directions… n Neuro-imaging

Questions or Comments?