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Phrase Structure Tree
Syntactic Rules
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Break down the sequence using a Phrase Structure Tree
Rules of allowable word sequences in a language
(grammatically correct)
Phrase structure
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sentences composed of smaller units (constituents)
article
Allowable Sequences
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Sentences: Phrase Structure Rules
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Noun Phrase + Verb Phrase
n Noun
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n Verb
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Some verbs do not require objects (intransitive)
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Set of complicated rules governing syntax
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n Verb:
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(auxiliary) + Verb: Ex: is chewing
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n Prepositional Phrase
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English -- meaning relies on word order
change order -- change meaning
ex: can't have two or more noun phrases
adjacent
interpret initial noun phrases as an adjective
red fire engine
fire engine red
n red engine fire
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Ex: Obtain
Ex: Sleep
We follow them (& know when they are violated)
May not be able to describe or explain
Preposition + Noun Phrase: Ex: over the moon
Are syntactical rules important?
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article adjective noun
Gets more complicated:
Some verbs require objects (transitive)
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Phrase:
Verb + Noun Phrase: Ex: ate the green grass
Verb + Prepositional Phrase: Ex: grazed in the grassy meadow
noun
Phrase Structure
Phrase:
(article) + (adjective) + noun : Ex: The spotted cow
Pronoun : Ex: She
adjective
What are we trying to accomplish
with language?
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Convey meaning or information
Syntactical rules – aid in conveying information
Information – represented in propositional
network (e.g., ACT) ???
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Grammatical Sentence
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Minimal requirements are a Noun Phrase and a Verb
Phrase
Jack ran – grammatical
n Jack tired – ungrammatical
n Why? May be rooted in organization of memory
Verb usage
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n Propositional
(subject) -- Noun Phrase
n Some
information about Doer (action or state) -- Verb Phrase
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e.g., Sleep -- He slept
(Propositional network -- certain relations require
object?)
Phrase Structure
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Word order important in specifying the doer,
the action, and the object
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Other verbs do not require an object (intransitive)
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Agent -- Relation -- (Object)
n Doer
Word Order
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e.g., Save -- He saved the dog
Networks
n Proposition:
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Some verbs require an object (transitive)
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provides a "road map" for understanding
Mapping onto propositional representation
Ate a worm the bird -- meaning is clear
Ate a shark the man -- meaning is ambiguous
Meaning changes if we change the word order
If road map unclear . . .
Psychological Reality of Syntax
He wants to discuss sex with Dr. Phil.
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Grammatical categories are psychologically real
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Evidence:
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Dr. P
e.g., Nouns vs. verbs
Kim et al (1991) – studied how we “verb” nouns
Treated differently than corresponding/similar irregular
verbs
Dr. P
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Examples
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Examples
Gretzky got a penalty for hitting the goalie with
a high stick.
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Gretzky high-sticked the goalie.
n Gretzky high-stuck the goalie.
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Brian needed nerves of steel to face the ordeal.
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Pete tried to stick the tape on the wall again and
again.
Benzinger was good at stealing bases.
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Pete re-sticked the tape on the wall.
n Pete re-stuck the tape on the wall.
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Examples
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General Patton ordered his artillery to form a
ring around the city.
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Songs of freedom ringed through the land.
Songs of freedom rang through the land.
Psychological Reality of Syntax
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Songs of freedom were ringing through the land.
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Process/organize by phrase structure
Example: Caplan (1972)
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He always puts the pig on a spit to roast it over a
fire.
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He quickly ringed the city with artillery.
n He quickly rang the city with artillery.
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Last night, Benzinger stealed second base twice.
Last night, Benzinger stole second base twice.
Examples
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Brian steeled himself for the ordeal.
Brian stole himself for the ordeal.
Again last night, he spitted the pig.
Again last night, he spat the pig.
Whenever I come up with a suggestion, he
always spits on it.
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Again last night, he spitted on my idea.
Again last night, he spat on my idea.
Caplan (1972)
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Sentences read to subjects
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constructed special sentences
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Most recent phrase – most active/accessible
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Now that artists are working fewer hours oil prints are rare
Now that artists are working in oil prints are rare
Ex: probed with "oil"
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Afterwards – Asked if a probe word was present?
faster in the first type of sentence -- oil in last phrase
slower in second type of sentence -- oil in first phrase
Probe words – identical in position & wording
Differ only in phrase (last vs. not last)
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Reality of Syntax
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Subject paced reading
Ex: Aaronson & Sarborough (1977)
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single word presentation
n Press
key to continue
paced reading”
golfcourse,
Mounts
Woods
bought
After
Tiger
soda.
draft
beat
cold
the
Dr.
on
a
n “subject
measured time spent on each word
n pauses between phrases
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Factors affecting comprehension
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Negative vs. Positive forms of sentences
Sherman (1976) -- tested comprehension
affirmative sentences
n 1 , 2 , 3 , or 4 negatives
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n ex:
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Passive Sentences
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active sentences typically easier to comprehend
sequence of doer, action, object
ex: Obler
Obler,, Fein, Nicholas, & Albert (1991)
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Few people strongly deny that the world is not flat
n The
n affirmative: 100%
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negatives: 59%
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Active advantage depends on meaning
The girl caught the ball
n The ball was caught by the girl
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woman rescued the dog
dog was rescued by the woman
94% correct on active
81% correct on passive
"I looked over, and there ain't wasn't nothing
there no more”
Caveat on Passive Sentences
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gave adults in their 30's active and passive sentences
n The
Comprehension
can't confuse subject and object
No advantage for active
Sentence Parsing
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How do we extract a sentence's phrase structure
and meaning?
Assign each word a syntactic role in that
sentence
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running -- adjective, noun, verb?
Evidence suggests that we parse and begin to
comprehend "on line”
actively setting up phrase structure while
sentence is coming in
Use both syntax and semantics
Extract phrases -- compile and then proceed
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Syntax as a guide to
parsing/comprehension
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Articles -- a noun is coming
ly -- signals an adverb – a verb is coming
Can’t have two nouns in a row
. . . was “verbed
“verbed”” . . .-.-- passive structure
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A dorgon was fuppily veeped by the vardy raglimore
raglimore..
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Who did what to whom?
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Minimal Attachment
Assumption of minimal attachment
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what is the simplest phrase structure that will
accommodate sentence up to this point?
e.g., simplest -- NP + V
Semantics as a guide to parsing
knowledge about the meaning and use of words
does the verb require an object?
if yes -- know that a noun phrase is coming
evaluate meaning before the end of the sentence
Evidence that we interpret on line
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Garden path sentences
The horse raced past the barn fell.
After the musician had played the piano was quickly
taken off the stage.
n Fat people eat accumulates.
n The old man the ships.
n The cotton clothing is made of grows in Mississippi.
n We painted the wall with cracks.
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Part of the way through the sentence – discover
phrase structure we are using doesn’t work
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