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Discourse Context

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  1. 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 Psyc / Ling / Comm 525 Fall 2010

  2. 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 ... Psyc / Ling / Comm 525 Fall 2010

  3. Prediction If people use discourse context immediately, • they'll read new lockfaster 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 lockfaster 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 Psyc / Ling / Comm 525 Fall 2010

  4. Tanenhaus, Spivey-Knowlton, Eberhard & Sedivy (Science, 1995) • 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 Psyc / Ling / Comm 525 Fall 2010

  5. 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 Psyc / Ling / Comm 525 Fall 2010

  6. Only 1 apple in display Ambiguous version Typical Result in 1-Ref Condition Unambiguous version Psyc / Ling / Comm 525 Fall 2010

  7. Ambiguous version Unambiguous version Typical Result in 2-Ref Condition 2 apples in display Psyc / Ling / Comm 525 Fall 2010

  8. Overall Results (the towel) Psyc / Ling / Comm 525 Fall 2010

  9. 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 ??? Psyc / Ling / Comm 525 Fall 2010

  10. The rest of the slides here I didn’t get to in class on 10/20 & won’t cover in class at all. Psyc / Ling / Comm 525 Fall 2010

  11. 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) vsNew 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 Psyc / Ling / Comm 525 Fall 2010

  12. 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. • Prosody • The subject in a basic SVO sentence can be the new information • If it isstressed • Several students missed class today. AMANDA was one of them. Psyc / Ling / Comm 525 Fall 2010

  13. 4. DefinitevsIndefinite 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 Psyc / Ling / Comm 525 Fall 2010

  14. 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 Psyc / Ling / Comm 525 Fall 2010

  15. 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" Psyc / Ling / Comm 525 Fall 2010

  16. 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 Psyc / Ling / Comm 525 Fall 2010

  17. DeepvsSurface 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 toochanges 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 Psyc / Ling / Comm 525 Fall 2010