Syntax 5

Syntax 5Nov 18, 2015 – DAY 35

Brain & Language

LING

4110-4890-5110-7960

NSCI

4110-4891-6110

Fall 2015

Course organization

Schedule:http://www.tulane.edu/~howard/BrLg/t1-Intro.html#schedule-of-topicsToday's chapter:http://www.tulane.edu/~howard/BrLg/t19-aIFG.htmlFun with https://www.facebook.com/BrLg15/Quiz before Thanksgiving will be in class & on Blackboard.

11/18/15

Brain & Language - Harry Howard - Tulane University

2

Grades

Q1Q2Q3Q4Q5Q6Q7MIN6554734AVG9.08.88.88.49.27.58.7MAX10101010101010

11/18/15

Brain & Language - Harry Howard - Tulane University

3

Combinatorial net 2

11/18/15

Brain & Language - Harry Howard - Tulane University

4

The lexical interface

11/18/15

Brain & Language - Harry Howard - Tulane University

5

Models of sentence processing

Traditional generative model

A separate mental module parses sentences just like we just did. Lexical access happens first.Then one syntactic hypothesis is considered at a time.There is no influence of meaning.

More recent interactive model

There is no separate module for parsingLexical access, syntactic structure assignment, and meaning assignment happen at the same time (in parallel).Several syntactic hypotheses can be considered at a time.

11/18/15

Brain & Language - Harry Howard - Tulane University

6

How to decide

?

On

-line

processing

Two types of processing

on-line

Happens in real time.Instructions for an experiment to test it:You will read a sentence, one word at a time. Push a key after each word.

off-line

Happens after the fact.Instructions for an experiment to test it:You will read a sentence.Point to the picture that describes it best.

11/18/15

Brain & Language - Harry Howard - Tulane University

7

Working memory & syntax

11/18/15

Brain & Language - Harry Howard - Tulane University

8

Left-to-right solution of arithmetic1 + 1 + 1 = ?(1 + 1) + 1 = ?2 + 1 = 3Left-to-right parsing of a sentence.[S [NP a cat] [VP is [PP on [NP the couch]]]]

S

NP

a cat

V

P

V

is

PP

on the couch

Working memory span or capacity

The amount of material that you can keep on your ‘scratch pad’ is known as your working memory span or capacity.How much is it?Miller’s number: 7 ± 2It varies a little from person to person and even from domain to domain in the same person.That’s the meaning of the “± 2”Working memory span can be impaired in brain injury.It has recently been shown to be correlated with fluid intelligence.

11/18/15

Brain & Language - Harry Howard - Tulane University

9

The working memory needed for parsing …

… is part of a general purpose working memory

Individual differences in working memory are implicated in strategies for understanding complex spoken sentences.

… constitutes its own specialized store of working memory.

Some patients who share severe deficits of general purpose working memory are still able to understand complex spoken sentences.Individual differences in working memory are usually not implicated in on-line language understanding.

11/18/15

Brain & Language - Harry Howard - Tulane University

10

syntax 4

Sentence comprehension and syntactic parsing

11/18/15

Brain & Language - Harry Howard - Tulane University

11

Syntax vs. pragmatics: Ferreira & CliftonSelf-paced reading (on-line) task

SentenceRelative clauseSubjectLatency at by1. The evidence examined by the lawyer shocked the jury.reducedinanimatesame as 32. The evidence that was examined by the lawyer shocked the jury.unreducedinanimatequicker than 13. The defendant examined by the lawyer shocked the jury.reducedanimatesame as 14. The defendant that was examined by the lawyer shocked the jury.unreducedanimatequicker than 3

11/18/15

Brain & Language - Harry Howard - Tulane University

12

The fact that there is no garden path at

by

in (3) shows that syntax can perform the parse without access to pragmatics.

Just & Carpenter

Low reading spanLatency at by

unreducedrelative clausereducedrelative clauseinanimatesubject~450 ms~500 msanimatesubject~450 ms~500 ms

High reading spanLatency at by

11/18/15

Brain & Language - Harry Howard - Tulane University

13

unreducedrelative clausereducedrelative clauseinanimatesubject~350 ms~400 msanimatesubject~425 ms~475 ms

Same as before: no competition from pragmatics to confuse (and slow down) syntactic parse

Different: latency is indeed longer in bottom cell than top cell of reduced relative clause > pragmatics creates a garden path

Why?

‘Cognitive capacity’Low span readers only have enough capacity to process syntactic cues; nothing is left over to process pragmatics > modular processing (syntax first).High span readers have enough capacity to process syntactic cues and pragmatics > interactive processing (all cues considered simultaneously).

11/18/15

Brain & Language - Harry Howard - Tulane University

14

Syntactic complexity

How about these sentences?8a) The dog chased the cat.8b) The cat hunted the rat.8c) The rat nibbled the cheese.9) The rat the cat hunted nibbled the cheese.10) The rat the cat the dog chased hunted nibbled the cheese.

11/18/15

Brain & Language - Harry Howard - Tulane University

15

Center embedding

11/18/15

Brain & Language - Harry Howard - Tulane University

16

9) The rat the cat hunted nibbled the cheese.

The rat which the cat hunted nibbled the cheese.

10) The rat the cat the dog chased hunted nibbled the cheese.

The

rat which the cat which the dog chased hunted nibbled the cheese.

How might this be processed?

11/18/15

Brain & Language - Harry Howard - Tulane University

17

thematic role for ‘the rat’

thematic role for ‘the cat’

thematic role for ‘the dog’

The parser encounters …

the rat > look for a predicate to supply a thematic role …

the cat > wait, put the previous search on hold & look for another predicate to supply a thematic role …

the dog > wait, put the previous search on hold & look for yet another predicate to supply a thematic role …

Ok, now I am lost.

push-down stack

Interim conclusion

The limit on center embedded is 2.Given that Miller’s number is much larger, it would appear that there is a working memory specialized for parsing.

11/18/15

Brain & Language - Harry Howard - Tulane University

18

‘Edge’ embedding does not create this problem

11/18/15

Brain & Language - Harry Howard - Tulane University

19

i) The dog chased the cat that hunted the rat that nibbled the cheese.

ii) The

dog that chased the cat that hunted the rat that nibbled the cheese was a dachshund.

Thinking about sentences, and science

Mary bought a book for John.The direct object THEME follows the verb in English.Which book did Mary buy for John?The direct object THEME follows the verb in English or precede its clause when it is introduced by which.John asked Mary about a student.TOPIC is the object of the preposition about.Which student did John ask Mary about?TOPIC is the object of the preposition about, or it precedes its clause when it is introduced by which.Is adding "it precedes its clause when it is introduced by which" a good idea?

11/18/15

Brain & Language - Harry Howard - Tulane University

20

Generalization

You should have gotten the idea that every statement that is made about NPs in English must be duplicated to take into account questions with which.But clefting requires a tripling of statements about NPs:This book is what Mary bought for John.Leprechauns is what John asked Mary about.And there are even more constructions that require even more duplication.Is this a good way to describe the grammar of English?NO! because we lose track of perfectly good generalizations like the direct object follows the verb or THEME is usually the direct object.Is there a principle of science that can help us out here?

11/18/15

Brain & Language - Harry Howard - Tulane University

21

Leprechauns!

Think of an explanation for

something:The Earth spinning on its axis makes day and night.The Earth spinning on its axis or leprechauns pushing it, makes day and night.Rain falls when water condenses in the atmosphere.Rain falls when water condenses in the atmosphere or leprechauns piss from clouds.Does adding leprechauns to all our explanations make them better?

11/18/15

Brain & Language - Harry Howard - Tulane University

22

Ockham’s razor, simplicity, economylex parsimoniae

Ockham’s razor is a principle that generally recommends selecting from among competing hypotheses the one that makes the fewest new assumptions.Einstein-ish: “Make things as simple as possible, but not simpler.”

11/18/15

Brain & Language - Harry Howard - Tulane University

23

Back to our sentences

The sentences and their leprechaunsMary bought a book for John.Which book did Mary buy for John?John asked Mary about a student.Which student did John ask Mary about?How to get rid of the leprechaunsMary bought a book for John.Which booki did Mary buy ____i for John?John asked Mary about a student.Which studenti did John ask Mary about ____i ?(b, d) are called filler-gap constructions, though the gap is also called a trace.

11/18/15

Brain & Language - Harry Howard - Tulane University

24

Final project

Improve a Wikipedia article about any of the topics mentioned in class or any other topic broadly related to neurolinguistics.Write a short essay explaining what you did and why you did it.Print the article before you improve it, highlighting any subtractions. Print the article after you improve it, highlighting your additions.

11/18/15

Brain & Language - Harry Howard - Tulane University

25

NEXT TIME

More syntax

11/18/15

Brain & Language - Harry Howard - Tulane University

26