1. Arguments for Nativism Various other facts about child language add support to the Nativist argument: • Accuracy (few ‘errors’) • Efficiency (quick, easy) • Uniformity (within and across languages) • Constrained (POS)

2. Poverty of the Stimulus If (i) children know X, and (ii) evidence for X is not sufficiently present in the input to children, then X must be innate.  Children come to know things that they should not know, given what they hear.

3. the girl is in the market Example of the POS: auxiliary inversion (Chomsky, 1971) (1)

4. Example of the POS: auxiliary inversion (Chomsky, 1971) (1) the girl is in the market

5. Example of the POS:auxiliary inversion (Chomsky, 1971) (1) Is the girl [t] in the market ?

6. Principle of Y/N Question Formation:  Move the auxiliary to the front of the sentence. This works for 99% of the sentences in English. But not all…

7. Sentences with Multiple Auxiliaries John is in the house now that it is raining.

8. Sentences with Multiple Auxiliaries John is in the house now that it is raining. Is John [t] in the house now that it is raining?

9. Sentences with Multiple Auxiliaries John is in the house now that it is raining. Is John [t] in the house now that it is raining? *Is John is in the house now that it [t] raining?

10. Revised Principle of Y/N Question Formation:  Move the first auxiliary to the front of the sentence. The girls is in the market John is in the house now that it is raining.

11. But… a. The child that is sitting on the floor is hungry. b. *Is the child that [t] sitting on the floor is hungry? c. Is the child that is sitting on the floor [t] hungry?

12. So what’s the principle? [The child that is sitting on the floor] is hungry. [The child that is sitting on the floor]

13. So what’s the principle? Is [the child that is sitting on the floor] [t] hungry?

14. So what’s the principle? • Linear Order Hypothesis (Incorrect): To make a yes-no question, front the first auxiliary. • Structural Dependency Hypothesis (Correct): In order to make a yes-no question, front the main auxiliary.

15. How does a child learn this? • The child must hear sentences of the following kind: Is the child that is sitting on the floor hungry? • Nativists argue such evidence is stunningly rare in CDS. • Crain & Nakayama (1987) show children aged 3;2 have knowledge of this principle.

17. Poverty of the Stimulus At its heart, the POS argument is a problem of INDUCTION. Induction: how do you go from individual examples to a generalized rule?

18. Induction A simple example: 1 2 … What’s the next number in this progression? 3? 4? 7?

19. The Induction Problem • You’re about to see 5 slides of 3 colored bars in frames. • The first 4 slides exhibit a property that you need to learn. • Decide whether or not the 5th slide exhibits the property in question.

20. 1

21. 2

22. 3

23. 4

24. ?

25. Answer • NO • The property in question in whether the area covered by the bars is greater than 50% of the area of the rectangle. • This generalization is more natural for pigeons to learn than for humans.

26. Try it again

27. 1

28. 2

29. 3

30. 4

31. ?

32. Answer • YES • Property in question in whether the 3 bars are unequal in height. • This generalization is more natural for humans than for pigeons.

33. Try it again

34. 1

35. 2

36. 3

37. 4

38. ?

39. Answer • YES • You only saw examples decreasing in height from left to right. But the generalization was still that the bars only had to be different heights.

40. Try it again

41. 1

42. 2

43. 3

44. 4

45. ?

46. Answer • YES • Property in question is whether the 3 bars are unequal in height. • But what about the 4th example? • Oh, that? It was a mistake.

47. The Induction Problem • You have to be able to discern the relevant dimension(s) • Any set of input data potentially allows an infinite number of generalizations. • How does an unbiased learner select the one correct hypothesis from amongst these infinite hypotheses?

48. Returning to Yes-No Question Formation • Linear Order Hypothesis (Incorrect): To make a yes-no question, front the first auxiliary. • Structural Dependency Hypothesis (Correct): In order to make a yes-no question, front the main auxiliary.

49. So how do kids learn the correct principle?

50. Children are born with the knowledge that language is dependent on structure, not linear order.