Presentation on theme: "Ashley David Sara McTaggart Annie Porter Ellen Ramsey"— Presentation transcript:
1 Ashley David Sara McTaggart Annie Porter Ellen Ramsey What infants know about syntax but couldn’t have learned: experimental evidence for syntactic structure at 18 months Jeffrey Lidz, Sandra Waxman, Jennifer FreedmanAshley DavidSara McTaggartAnnie PorterEllen Ramsey
2 Background Information Two major views:Nativist view:Grammar acquisition depends on innate structures in addition to inputMajor support: “poverty of the stimulus”General learning view:Linguistic input is sufficient in explaining the child’s acquisition of grammarUses general purpose learning mechanismsPoverty of the stimulus– input underdetermines the linguistic representations of the adult grammarBackground Information
3 Support for the Nativist View Poverty of the stimulus:Looking at NP structure and AnaphorsPossibility of two representations of NP (containing a det, adj, and noun):Flat NestedAnaphors:Anaphoric elements substitute only for constituents.Example:I’ll play with this red ball and you can play with that one.What is one referring to?[ ball ][ red ball ]Background Information
4 Noun Phrase Representations Support for the Nativist ViewNoun Phrase RepresentationsFlat structurehypothesisNPdet adj Nothe red ballNested structure hypothesisNPdet N’adj N’Nothe red ballThe nested structure accounts for the anaphoric use of one since it is under this structure that red ball is represented as a constituent.Background Information
5 Flat vs Nested structure in children… One is anaphoric to N’ and this is only possible in the nested structureBUTEven if a child used the flat structure, finding evidence that they were wrong would be difficult because every situation where one= [N’ red ball] true also makes one= [N°ball] trueBackground Information
6 Flat vs Nested structure in children… Background Information …continuedConsider the following situation which would be needed to provide evidence against the flat structure:Sally has a red ball but Julie doesn’t have one.Imagine that Julie has a ball, but it’s a blue ball.In this case, interpreting one as referring to N° is false since one would be referring to ball, but Julie has a ball, just not a red ball.SallyJulieBackground Information
7 Flat vs Nested structure in children… …continuedA child coming across this type of situation would have to come to the conclusion that their flat structure hypothesis was false and would have to change to the nested NP structure in order to have correct grammar.These types of situations are rare. So, if a learner started with the flat structure, it is possible that they would never get the evidence to lead them to the correct structure.Because there is no evidence of English speakers having a flat structure grammar, the idea is not considered. We assume the nested structure.Background Information
8 Support for a nested structure… Hamburger & Crain (1984) found that children do represent the NP with a nested structure AND that they know one is anaphoric to N’…BUTStill not enough to describe how learners’ structure begins- as flat structure that matures into nested structure OR as a nested structure from the startBackground Information
9 Corpus analysis Support for the Nativist View Examined linguistic input of (2) children using CHILDES (found 792 anaphoric uses of one)Experimenters were interested in looking at the possibility of one as anaphoric to N’ not being available to learnersExamined structures of antecedentMain idea: If there are a lot of instances of one referring unambiguously to N’- it is possible that input is significant for child to learn syntactic properties of one (general learning view)Results: In 95% of the cases, the antecedent did not provide unambiguous indication of one referring to N’Conclusion: Linguistic input is insufficient for learner to know that one is anaphoric to N’ (nested structure) which supports the nativist viewAntecedent is important because it has the potential of indicating whether one refers unambiguously to N’
10 ExperimentationResearch question: Do infants know that one is anaphoric to N’ and thus have a nested NP structure?Prediction: They do [have a nested structure] and will therefore interpret one as anaphoric to N’.
11 Subjects Experimentation 24 English-speaking children (12 male; 12 female)Age: 16m; 23d – 18m;15d (ave: 18m;3d)Selected because just beginning to produce more than one-word utterancesTwo taken out because of failure to complete experiment
12 Materials Experimentation Auditory stimuli Visual stimuli Sentences & questions recorded in infant-friendly voice to be used as audio track with video in testingUsed objects whose names are normally recognized by infants of ~13 months+ (a bottle, a car, a shoe, a bear)Visual stimuliConstructed using computer drawing programBrightly coloured & large to attract attentionOf equal salience(Two) objects displayed on split-screen (side-by-side)
13 Set-up Experimentation Records infant looking times & locations CamcorderPresents audio-visual materials61 in. LCD screen20 in.20 in.12 in.12 in.18 in.18 in.80 in.Projects imagesCamcorderChild (sitting on booster seat)
14 Procedure Experimentation Playroom- Testing room- parents were explained experiment, signed consent form, and completed vocabulary checklistTesting room-Parents instructed not to interact with child- sat behind child and wore visor that blocked view of screen so not to influence child’s direction of gaze
15 Procedure (continued) ExperimentationProcedure (continued)Familiarization PhaseImage of single object presented 3xAppeared alternating fashion on L or R screen accompanied by a recorded voiceObject was presented with a NP that included adet + adj + noun (example: Look! A yellow bottle.)Testing PhaseTwo objects appeared simultaneously side-by-side (on either side of the screen’s midline)Both images were from the same category as the familiarization object BUT only one was the same colour4 trials that each included these two phases
16 Procedure (continued) ExperimentationProcedure (continued)Control condition-In the test phase, the child heard a neutral phrase:Now look. What do you see now?Anaphoric condition-In the test phase, the child heard a phrase containing the anaphoric one:Now look. Do you see another one?Each condition consisted of 4 trials (familiarization and test phase)Children were randomly assigned to either conditionTest phase lasted 8 secondsEntire experiment lasted 3 minutes 46 seconds
17 Familiarization Phase Example of Control ConditionFamiliarization PhaseLook! A brown bear!
18 Familiarization Phase Example of Control ConditionFamiliarization PhaseWow! A brown bear!
19 Familiarization Phase Example of Control ConditionFamiliarization PhaseLook! A brown bear!
20 Now look. What do you see now? Example of Control ConditionTest PhaseNow look. What do you see now?
21 Familiarization Phase Example of Anaphoric ConditionFamiliarization PhaseLook! A yellow bottle.
22 Familiarization Phase Example of Anaphoric ConditionFamiliarization PhaseWow! A yellow bottle.
23 Familiarization Phase Example of Anaphoric ConditionFamiliarization PhaseLook! A yellow bottle.
24 Now look. Do you see another one? Example of Anaphoric ConditionTest PhaseNow look. Do you see another one?
25 Coding & Predictions Experimentation Coding Predictions Durations of looking time to the L or R test image were coded afterwards by a single coder who watched the video of the sessionAnother coder coded 25% of the dataInter-coder reliability- 96%PredictionsControl condition- linguistic stimulus does not favour one image over the other so expect child to look longer at novel imageAnaphoric condition- where child looks should indicate their type of structureIf represent with flat structure- either image could be referents of the nounLinguistic stimulus is uninformativeShould see same as control (look to novel image)If represent with nested structure- should have preference for image that matches one as anaphoric to N’ (look to familiar object)Preferential looking task- infants look longer at image that match linguistic stimulus if one is available
26 Results Experimentation What does this imply??? Conclusion Control conditionPreference for novel imageAnaphoric conditionMore attention to familiar image than novel imageSubjects in the anaphoric condition were more likely to look at the familiar image than were the subjects in the control conditionConclusionBy 18 months of age infants interpret one as anaphoric to N’ and therefore represent NPs with a nested structureWhat does this imply???
27 ExperimentationFigure 1. Mean looking time (in seconds) to the two test images in each condition
28 Other possible interpretation of results… ExperimentationOther possible interpretation of results…It could be the case that infants treat one as anaphoric to N°BUTwhen they are asked to pick out another image that denotes, for them, N°- they have a preference for the familiar image (familiarity bias)SO…Conducted a control experiment to make sure this was not the case.
29 Control Experiment Same as Experiment with the following exception… Test phase, two conditions:Noun condition- children asked question that contained only the noun presented during familiarization (N°)Example: “Do you see another bottle?”Adjective-Noun condition- children asked question that had adj-noun combination heard in familiarization (N’)Example: “Do you see another yellow bottle?”
30 Predictions and Results Control ExperimentPredictions and ResultsNoun Condition (where both are nouns):If children had a familiarity bias- would expect to see children looking longer at the familiar imageIf children do not have a familiarity bias- would expect child to look at either image in the noun conditionAdj-Noun conditionWould expect child to look longer at the familiar object since only that image corresponds with the N’What found
31 Control ExperimentFigure 2. Mean looking time (in seconds) to the two test images in the control experiments
32 Interpretation of results… Control ExperimentInterpretation of results…Because no familiarity bias was found- conclude that children choose familiar object (in anaphoric condition) because it matches their nested NP structure
33 DiscussionLearners just beginning to combine words already have a rich syntactic representationSupport for poverty of the stimulusLearners never consider that an element could be anaphoric to N° but behave like adults who consider one as anaphoric to N’Support for nativism- but experimenters still acknowledge role of inputEND