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 Freedman
Ashley David
Sara McTaggart
Annie Porter
Ellen Ramsey

2. Background Information
Two major views:
Nativist view:
Grammar acquisition depends on innate structures in addition to input
Major support: “poverty of the stimulus”
General learning view:
Linguistic input is sufficient in explaining the child’s acquisition of grammar
Uses general purpose learning mechanisms
Poverty of the stimulus– input underdetermines the linguistic representations of the adult grammar
Background Information

3. Support for the Nativist View
Poverty of the stimulus:
Looking at NP structure and Anaphors
Possibility of two representations of NP (containing a det, adj, and noun):
Flat Nested
Anaphors:
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 View
Noun Phrase Representations
Flat structure
hypothesis NP
det adj No
the red ball
Nested structure hypothesis NP
det N’
adj N’ No
the red ball
The 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 structure
BUT
Even 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] true
Background Information

6. Flat vs Nested structure in children… Background Information
…continued
Consider 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.
Sally
Julie
Background Information

7. Flat vs Nested structure in children…
…continued
A 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’
…BUT
Still not enough to describe how learners’ structure begins- as flat structure that matures into nested structure OR as a nested structure from the start
Background 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 learners
Examined structures of antecedent
Main 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 view
Antecedent is important because it has the potential of indicating whether one refers unambiguously to N’

10. Experimentation
Research 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 utterances
Two 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 testing
Used objects whose names are normally recognized by infants of ~13 months+ (a bottle, a car, a shoe, a bear)
Visual stimuli
Constructed using computer drawing program
Brightly coloured & large to attract attention
Of equal salience
(Two) objects displayed on split-screen (side-by-side)

13. Set-up Experimentation Records infant looking times & locations
Camcorder
Presents audio-visual materials
61 in. LCD screen
20 in.
20 in.
12 in.
12 in.
18 in.
18 in.
80 in.
Projects images
Camcorder
Child (sitting on booster seat)

14. Procedure Experimentation Playroom- Testing room-
parents were explained experiment, signed consent form, and completed vocabulary checklist
Testing 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)
Experimentation
Procedure (continued)
Familiarization Phase
Image of single object presented 3x
Appeared alternating fashion on L or R screen accompanied by a recorded voice
Object was presented with a NP that included a
det + adj + noun (example: Look! A yellow bottle.)
Testing Phase
Two 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 colour
4 trials that each included these two phases

16. Procedure (continued)
Experimentation
Procedure (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 condition
Test phase lasted 8 seconds
Entire experiment lasted 3 minutes 46 seconds

17. Familiarization Phase
Example of Control Condition
Familiarization Phase
Look! A brown bear!

18. Familiarization Phase
Example of Control Condition
Familiarization Phase
Wow! A brown bear!

19. Familiarization Phase
Example of Control Condition
Familiarization Phase
Look! A brown bear!

20. Now look. What do you see now?
Example of Control Condition
Test Phase
Now look. What do you see now?

21. Familiarization Phase
Example of Anaphoric Condition
Familiarization Phase
Look! A yellow bottle.

22. Familiarization Phase
Example of Anaphoric Condition
Familiarization Phase
Wow! A yellow bottle.

23. Familiarization Phase
Example of Anaphoric Condition
Familiarization Phase
Look! A yellow bottle.

24. Now look. Do you see another one?
Example of Anaphoric Condition
Test Phase
Now 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 session
Another coder coded 25% of the data
Inter-coder reliability- 96%
Predictions
Control condition- linguistic stimulus does not favour one image over the other so expect child to look longer at novel image
Anaphoric condition- where child looks should indicate their type of structure
If represent with flat structure- either image could be referents of the noun
Linguistic stimulus is uninformative
Should 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 condition
Preference for novel image
Anaphoric condition
More attention to familiar image than novel image
Subjects in the anaphoric condition were more likely to look at the familiar image than were the subjects in the control condition
Conclusion
By 18 months of age infants interpret one as anaphoric to N’ and therefore represent NPs with a nested structure
What does this imply???

27. Experimentation
Figure 1. Mean looking time (in seconds) to the two test images in each condition

28. Other possible interpretation of results…
Experimentation
Other possible interpretation of results…
It could be the case that infants treat one as anaphoric to N°
BUT
when 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 Experiment
Predictions and Results
Noun Condition (where both are nouns):
If children had a familiarity bias- would expect to see children looking longer at the familiar image
If children do not have a familiarity bias- would expect child to look at either image in the noun condition
Adj-Noun condition
Would expect child to look longer at the familiar object since only that image corresponds with the N’
What found

31. Control Experiment
Figure 2. Mean looking time (in seconds) to the two test images in the control experiments

32. Interpretation of results…
Control Experiment
Interpretation 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. Discussion
Learners just beginning to combine words already have a rich syntactic representation
Support for poverty of the stimulus
Learners 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 input
END