Language Use and Understanding

Language Use and Understanding BCS 261 LIN 241 PSY 261 CLASS 6: BRENNAN -CENTERING ATTENTION IN DISCOURSE

Announcements • Hand out guidelines for presentations • Hand out research project assignment • Changes to syllabus: • Branigan et al. & Snedeker et al. are moved back, in-class meetings moved up to Feb. 23 • Fodor moved to March 22 • Results due March 24

So far… • Haviland and Clark: Listeners try to link incoming speech with given information, which is easier with a direct antecedent than indirect one, and easier when there is a definite antecedent than an indefinite one • Arnold et al: The bias toward given referents occurs for fluent definite NPs, and disfluent NPs give rise to a bias toward new (unmentioned) referents.

Larger question • How do conversation participants build a mental model of the discourse that makes some things more accessible than others?

H&C: things in your mental model (given) will be more accessible than things that aren’t (new) • A et al: It’s more than just given/new, expectancy (from things like disfluency) is relevant • Brennan: It’s more than just given/new, speakers make detailed choices in how to present information that indicates where their focus of attention is

Some choices in production • Refer to something as subject or nonsubject • John walked in the room. • I saw John walk in the room. • Form of reference • He walked in the room. • John walked in the room.

A model of global & local discourse structure • Global structure: • Focus spaces on stack (last on, first off) • What’s on top is in focus • Discussion Q: Using a Stack as a model for conversational information storage seems like an inadequate analogy to me. What about when something mentioned awhile ago is forgotten and not mentioned again? A Stack does not allow things to be taken off from the bottom, only the top. (Nicole Dobrowolski)

Centering: Local focusing of attention • Forward-looking centers -- all (nominal) entities, ranked (provide possible antecedents for later referents) • Backward-looking center -- At any moment, the one entity the discourse is “about” (the “topic”). Definition: the thing that corefers with the highest-ranked Cf from the previous utterance. • Preferred center -- the most highly ranked forward-looking center

How are forward-looking centers ranked? • Syntactic prominence of preceding utterance: • subject > object > object-of-preposition • Other information could be relevant too • Use of referring expressions (pronouns, nouns, etc.) • Thematic roles • Focusing constructions • Etc.

Example • And now the Wolverines have the ball • They’re going down • Number thirthy passes it off to forty-one • Forty-one goes up for the shot • And he misses Backward-looking center (also always preferred Center here) Forward-looking centers

Example where Cb ≠ Cp • Janet wanted some ice cream, • So John gave her a pint of chocolate mint chip. • Her = backward-looking center • John = preferred center

Comprehension vs. Production • Several studies show that centering accounts for patterns in comprehension. E.g., pronouns are undestood faster when they refer to the center than the noncenter • Brennan (1995) looks at production

Listener-centered vs. Speaker-centered • An unanswered question: • Do speakers make production choices to make things easier for the listener, e.g. using pronouns for things assumed to be in the listener’s focus of attention? • Or do they just make choices based on their own attentional state? • Discussion Q: It seems like this is done very automatically and is mostly common sense. We use pronouns for our own benefits as well as for the understanding of those who are listening to us. Does anyone else think that this is very excedingly similar to the Given-New strategy? (Jessica DeSisto)

Research Questions • Subject vs. Object • Prominent entities mentioned as subjects more than objects • Pronoun vs. Name • Backward centers (subjects) should be pronominizlized • Non-centers (objects) should not

Method • Describe b-ball game to addressee • Addressee had to answer questions at arbitrary points (e.g., “who has ball now?”) to motivate a detailed description of game • Speech transcribed and analyzed • Action segmented into propositions • Speech segmented into “reference events” that corresponded to each proposition • Reference event scoded for high/low prominence based on the action of the game

Results • Overall • 73% of propositions described • More high than low prominence described

Subject vs. Object • Prominent entities (those with possession of ball during high-prominent event) were introduced as subjects more than low-prominent entities, and as objects • SUBJECT OBJECT • High-prominent: 53.8% 29.1% • Low-prominent: 35.1 % 52.3%

Pronoun use • Is a pronoun or name used in the SECOND utterance of a reference event? • More pronouns in high (60.5% )than low (27.7%) prominence events • Supports idea that pronouns are used for entities that the speaker and listener are attending to

Pronoun use, cont. • Re-referring to object - pro or name? • Back to forty-one • …and he shoots • …and forty-one shoots • …who shoots • Full verbatim NP: 85/367 (23%) • Pronoun: 23/367 (6%)

Prosody • Increased duration, intensity, higher pitch signal prosodic stress • Stress could be one way of marking that something is moving into the center of attention

Prosody • Entities introduced as full NP objects • Set 1 -- syntactically centered with an NP in subject position • Back to forty-one • Fory-one shoots • He scores • Set 2 -- not syntactically centered • Back to forty-one • He scores • Results: Set 2 pronouns longer than Set 1

Discussion Questions • Does accenting and other forms of linguistic "attention getting" map directly onto the centering theory, or is it just another aspect that Brennan looked at in her study? In other words, is it either that the speaker uses pronouns OR accenting to make something salient, or that the speaker uses pronouns AND accenting to make something salient? (Jesse Blake) • The study determined that pronoun usage was not significantly governed by recency. Could this be due to the fact that all the subjects in these NPs were male and the use of pronouns might have been confusing or ambiguous? (Beth Riina)

How would centering account for multiple pronoun usage? (Nicole Dobrowolski) • Jenna told Tommy • that she would take out the garbage for him • but he insisted on doing it • so she let him.")

Would these findings be different if the conversation topic was chosen by the students or if the students played basketball themselves (find describing basketball much easier)? (Jessica DeSisto)

In the experiment with the basketball game, could there be other factors regarding the result that supposedly supported the prediction that "centers" were more likely to be followed by pronoun usage in place of the subject? It seems as if maybe pronouns were simply used out of ease in these cases. High-prominance events were labelled as such because they were supposed to be more attention getting, and in this case, the average high-prominance event seemed to simply involve more steps occuring faster than the low-prominance events. Could subjects just use pronouns to save time as they attempt to explain a fast-paced event? (Anthony Shook)

Language Use and Understanding