Transcript 10 - Tulane University

SYNTAX 4
NOV 16, 2015 – DAY 34
Brain & Language
LING 4110-4890-5110-7960
NSCI 4110-4891-6110
Fall 2015
11/16/15
Brain & Language - Harry Howard - Tulane University
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Course organization
• Schedule:
• http://www.tulane.edu/~howard/BrLg/t1-Intro.html#schedule-oftopics
• Today's chapter:
• http://www.tulane.edu/~howard/BrLg/t19-aIFG.html
• Fun with https://www.facebook.com/BrLg15/
• Quiz before Thanksgiving will be in class & on
Blackboard.
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Grades
Q1
Q2
Q3
Q4
Q5
Q6
Q7
MIN
6
5
5
4
7
3
4
AVG
9.0
8.8
8.8
8.4
9.2
7.5
8.7
MAX
10
10
10
10
10
10
10
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COMBINATORIAL NET 2
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The lexical interface
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What does it mean to lead someone
down the garden path?
• The Cambridge
Dictionary of American
Idioms says that the
negative connotation of
‘leading someone down
the garden path’ is
“based on the idea that a
path in a garden is very
pleasant, so someone
who is brought along it
can be deceived without
noticing it.”
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A different kind of problem
1. The old man the boat.
2. The man whistling tunes pianos.
3. The cotton clothing is made of grows in Mississippi.
4. The complex houses married and single soldiers and
their families.
5. The author wrote the novel was likely to be a bestseller.
6. The tomcat curled up on the cushion seemed friendly.
7. The horse raced past the barn fell.
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SYNTAX 4
Sentence comprehension and syntactic parsing
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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 parsing
• Lexical access, syntactic structure assignment, and meaning
assignment happen at the same time (in parallel).
• Several syntactic hypotheses can be considered at a time.
• How to decide?
• On-line processing
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Two types of processing
on-line
off-line
• Happens in real time.
• Happens after the fact.
• Instructions for an
• Instructions for an
experiment to test it:
experiment to test it:
• You will read a sentence,
• You will read a sentence.
one word at a time.
• Push a key after each word.
• Point to the picture that
describes it best.
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Working memory
• How would you solve this arithmetic problem?
• 1+1+1=?
• (1 + 1) + 1 = ?
• 2+1=3
• So you need to store the second half of the problem as you calculate
the first half.
• The prototypical example is keeping a telephone number in
mind as you dial it:
• 862-3417
• This sort of storage is known as working memory, and has
been variously characterized as:
• a scratch pad,
• a temporary work space,
• a buffer.
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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 ± 2
• It 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.
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Short-term memory
• There is also something called short-term memory, which
I can never understand how it is different from working
memory.
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Fluid vs. crystallized intelligence
• Fluid (Gf) and crystallized (Gc) intelligence are factors of
general (G) intelligence.
• Fluid intelligence is the capacity to think logically, recognize
patterns, and solve problems in novel situations.
• Crystallized intelligence is the ability to use skills, knowledge, and
experience. It improves somewhat with age, as experiences tend to
expand one's knowledge.
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Back to syntax
• Parsing a sentence also exercises working memory.
• [S [NP a cat] [VP is [PP on [NP the couch]]]]
S
VP
NP
a cat
V
is
PP
on the couch
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One or two working memories?
• There is some debate over whether the working memory
needed for parsing is part of a general purpose working
memory or constitutes its own specialized store of working
memory.
• Evidence for the latter
• Some patients who share severe deficits of general purpose working
memory as assessed by attention span tests are still able to
understand complex spoken sentences.
• Individual differences in working memory are usually not implicated in
on-line language understanding.
• HH: does this mean that language is more an aspect of crystalized
intelligence than fluid intelligence?
• Evidence for the former
• Individual differences in working memory are implicated in strategies
for understanding complex spoken sentences.
• Ingram says it’s a tie.
• I am going to try to test this in the next experiment.
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Some relevant tasks
• Sentence processing
• Self-paced reading:
• A sentence is presented as a series of words on a computer monitor,
and the subject presses a key on the keyboard after each word.
• The horse raced past the barn fell.
• Working memory
• Attention span
• How many digits can the subject remember and recall in normal or
reverse sequence?
• Verbal working memory ~ reading/listening span
• The subject reads/hears a series of sentences presented as a block.
• How many sentences can the subject recall the last word of?
• This span correlates highly with verbal SAT scores.
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Syntax vs. pragmatics: Ferreira & Clifton
Modified from Ingram p. 271; see Figure 13.1
Sentence
Relative
clause
Subject
Latency at by
1. The evidence examined by
the lawyer shocked the jury.
reduced
inanimate
same as 3
unreduced
inanimate
quicker than 1
reduced
animate
same as 1
unreduced
animate
quicker than 3
2. The evidence that was
examined by the lawyer
shocked the jury.
3. The defendant examined by
the lawyer shocked the jury.
4. The defendant that was
examined by the lawyer
shocked the jury.
The fact that there is no garden path at by in (3) shows that
syntax can perform the parse without access to pragmatics.
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Brain & Language - Harry Howard - Tulane University
Just & Carpenter
see Figure 13.2
Low reading span
Latency at by
High reading span
Latency at by
unreduced
relative
clause
reduced
relative
clause
unreduced
relative
clause
reduced
relative
clause
inanimate
subject
~450 ms
~500 ms
inanimate
subject
~350 ms
~400 ms
animate
subject
~450 ms
~500 ms
animate
subject
~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
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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).
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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.
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Brain & Language - Harry Howard - Tulane University
NEXT TIME
More syntax
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