Discourse Context. What are Non-minimally Attached PPs? They modify the NP they follow When does an NP need modification? When it wouldn’t be clear in context who or what it refers to If you see/hear The doctor examined the patient with ... - PowerPoint PPT Presentation
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10/20/10 Psyc / Ling / Comm 525 Fall 2010 Discourse Context • What are Non-minimally Attached PPs? – They modify the NP they follow – When does an NP need modification? – When it wouldn’t be clear in context who or what it refers to • If you see/hear The doctor examined the patient with ... – In a context where there are several patients in the waiting room – You may expect what follows to tell you which patient is meant – i.e., context may lead you to expect a Non-minimal Attachment
Transcript
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Discourse Context• What are Non-minimally Attached PPs?
– They modify the NP they follow– When does an NP need modification?– When it wouldn’t be clear in context who or what it refers to
• If you see/hear The doctor examined the patient with ...– In a context where there are several patients in the waiting
room– You may expect what follows to tell you which patient is
meant– i.e., context may lead you to expect a Non-minimal
Attachment
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Altmann & Steedman(1988)
Contexts:A burglar broke into a bank carrying some dynamite. He planned to blow open a safe. Once inside, he saw that there was ...
• 2-safe context:... a safe with a new lock and a safe with an old lock.
• 1-safe context: ... a safe with a new lock and a strongbox with an old lock.
• Target Sentences:MA: The burglar blew open the safe with the dynamite and ...NMA: The burglar blew open the safe with the new lock and ...
10/20/10 Psyc / Ling / Comm 525 Fall 2010
• Prediction If people use discourse context immediately,
– they'll read new lock faster than dynamite after the 2-safe context
– because they need new lock to know which safe is meant
• Results (Moving-Window RT)– People did read new lock faster than dynamite after 2-safe
context– i.e., the Non-Minimally Attached sentence was easier than the
Minimally Attached sentence• Suggests people don’t always try the simpler structure 1st
– What they try first seems to depend on the discourse context– BUT, these results have been notoriously difficult to replicate!
• What if the context comes from the world rather than discourse?– If that influences parsing, the system is clearly interactive
• Head-mounted eyetracker• Track eyes while people look at visual scenes &
hear spoken instructions– They usually look at objects before reaching for them– So eye movements can show what they’re thinking of
reaching for, based on how they’re understanding a sentence so far
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Procedures• People looked at displays of 4 objects while hearing
instructions like:– Put the apple on the towel in the box.– Ambiguous between:
• Put the apple on the towel in the box. towel = destination (MA)
• Put the apple on the towel in the box. towel = modifier (NMA)
• The visual scene had either 1 or 2 apples present– If visual context influences parsing, then when there are 2
apples:• They should think PP modifies it, to pick out which apple• So they should not think the towel is a destination & thus
should not look at it (much)• - i.e., They should prefer the Non-Minimal Attachment
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Typical Result in 1-Ref Condition
Only 1 applein display
Unambiguous version
Ambiguous version
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Typical Result in 2-Ref Condition
Ambiguous version
Unambiguous version
2 applesin display
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Overall Results
(the towel)
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Interpretation• When there were 2 apples, people rarely looked
at the empty towel– Suggests rarely considered it as a possible destination
• Thus, that they did not always try MA first– So, non-linguistic visual context immediately
constrained interpretation – So, sentence comprehension processing is interactive
• Whether you believe this interpretation– Depends on whether you think people would move
their eyes to the empty towel if they briefly misparsed the sentence & thought it was a destination ???
10/20/10 Psyc / Ling / Comm 525 Fall 2010
The rest of the slides here I didn’t get to in class on 10/20 & won’t coverin class at all.
10/20/10 Psyc / Ling / Comm 525 Fall 2010
Discourse• Discourse = Any kind of connected sentences
– (Harley restricts this term to speech – idiosyncratic!)
• Coherence = How well the sentences are connected– Requires some kind of links between sentences
• Given (= Old, Presupposition) vs New Information– Most sentences include something old that links it to the prior
discourse– plus the new information that this sentence conveys
• Given = what comprehender already knows– From discourse or non-linguistic context or world knowledge or ...
• New = what comprehender doesn’t already know
• Topic shifts– If a sentence changes the topic, people often use cues like
• Oh, by the way ...• Anyway, ... to come back to the former topic
10/20/10 Psyc / Ling / Comm 525 Fall 2010
How Given & New InformationConveyed (in English)
1. Default word order:– In a basic SVO sentence in discourse– Subject = given, Predicate = new– Several students missed class today. One of them was Amanda.
2. Special word orders– If what should be the subject is new information, special
constructions can be used to put it in the predicate instead– Passive
• I heard Lee was in an accident. He was hit by a truck.– Clefts
• I heard Lee was in an accident. It was a truck that hit him.• I heard Lee was in an accident. What hit him was a truck.
3. Prosody• The subject in a basic SVO sentence can be the new information
• If it is stressed• Several students missed class today. AMANDA was one of
them.
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4. Definite vs Indefinite Determiners– Indefinite determiners usually introduce new information
• I've decided to buy a piano.– Definite determiners usually refer back to old information
• I have a piano and an electronic keyboard.• The piano sounds much better than the keyboard.
– The information can be old without having been explicitly mentioned
• I went to a music store yesterday. The pianos were expensive.
– Exception in casual speech:• This is definite, but can introduce new entity in discourse
– I met this guy at a party last night. He turned out to be ... vs
– I met a guy at a party last night. He turned out to be ...
• It's a signal that you're going to say more about him– i.e., it focuses the listener's attention on him
10/20/10 Psyc / Ling / Comm 525 Fall 2010
5. Anaphoric Reference– Anaphor = Word/phrase referring to something already in
discourse– Co-reference = 2 or more references to the same entity
• I have a piano and an electronic keyboard. The piano sounds much better than the keyboard.
– the piano & the keyboard = Anaphors– a piano & a keyboard = Antecedents of the anaphors
• Several students missed class today. One of them was Amanda.
– them = Anaphor– several students = Antecedent
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• The antecedent can be implied rather than explicitly mentioned– I went to a music store yesterday. The pianos
were expensive.– I gave my son a driving lesson yesterday.
Next time I think I'll use the OLD car.
• Occasionally, the "antecedent" follows the anaphor (= Cataphor)– Even though I know she means well, my
mother drives me nuts.• she = Anaphor• my mother = "Antecedent"
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Some Different Types of Anaphors
• Pronouns– I bought a new hammer. It broke the first time I used it.
• Definite NPs– I bought a new hammer, some nails, and several screwdrivers. The hammer broke the first time I used it.
• VP "do" Anaphor– I need a new hammer and Pat does, too.
• Anaphors signal that you're still talking about same things– Not using one where you could sounds awkward and sometimes
suggests you're talking about a new thing• I bought a new hammer. A hammer broke the first time I
used it.• Repeated Name Penalty
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Deep vs Surface Anaphors(Hankamer & Sag)
• "do it" Anaphor (= Deep)– Somebody had to take out the garbage so I did it .– The garbage had to be taken out so I did it .
• In both cases, did it means "took out the garbage".• It doesn't matter whether the antecedent was active or passive
Compare with:• VP ellipsis Anaphor (= Surface)
– The fleas were biting the dogs and the cats were, too.– The dogs were bitten by the fleas and the cats were,
too.• The meaning of the anaphor were too changes depending on
whether its antecedent active or passive• So, interpreting a surface anaphor requires memory for details
about the form of its antecedent
• Surface anaphors must immediately follow their antecedents• There can't be any intervening phrases
