Speakers Reduce Because of Their Own Internal Representations

Jason KahnJennifer Arnold

UNC – Chapel Hill

You really have to watch Federer to understand the beauty of top-flight sports

performance.

Sure, but do you think tennis is as accessible to middle America as

football?

Sure, but do you think tennis is as accessible to middle America as

football?

You really have to watch tennis to understand the beauty of

top-flight sports performance.

Repeated Mentions Get Reduced (e.g. Bard et al., 2000; Fowler & Housum, 1987)

You really have to watch tennis to understand the

beauty of top-flight sports performance.

Linguistically Given Discourse Status

…tennis…

+givenness +predictability

You really have to watch Federer to understand the beauty of top-flight sports

performance.

…tennis…

Linguistically New Discourse Status

-givenness -predictability

General Questions

• What mechanism drives reduction?

• Does it involve audience design?

Audience Design

• Broadly speaking, designing utterance with audience in mind

• When it comes to acoustic reduction…– Joint Discourse Status – represented explicitly,

defined as shared information– Facilitated processing• For the speaker• For the listener

Why shorter duration on second mention?

Joint discourse status

Givón, 1983; Grosz et al., 1995

“Tennis”

Why shorter duration on second mention?

Speaker-internal Activation(The alternative - our proposal)

“Tennis”

Research Questions

• Must we explicitly represent discourse status for the purposes of reduction?– Or can we account for the same data by focusing

on the activation of other necessary representations?

• Must we explicitly represent the listener’s knowledge? – Or is audience design not the primary motivator?

Joint Discourse Status

CONCEPTUALIZATION STAGE

DISCOURSE STATUS(given vs. new)

(what speaker and listener both know)

FORMULATION STAGE

ARTICULATION STAGE

Adapted from Levelt (1989), Schmitt, Meyer & Levelt (1999), and van der Meulen, Meyer, & Levelt (2001)

Joint Discourse Status

CONCEPTUALIZATION STAGE

DISCOURSE STATUS(given vs. new)

(what speaker and listener both know)

“tennis”

Topic continuity tracks givenness information - in other words, givenness also creates predictability information

Fowler & Housum, 1987; Prince 1992

+givenness +predictability

CONCEPTUALIZATION STAGE

FORMULATION STAGE

ARTICULATION STAGE

Activation-based

Adapted from Levelt, 1989; c.f. Balota, Boland & Shields, 1989; Bard et al., 2000; Bell et al., 2009

Activation-based

CONCEPTUALIZATION STAGE

FORMULATION STAGE

“tennis”

Both predictability and givenness should create activation, and thus should be separable

givenness

predictability

Linguistic vs. Non-linguistic Givenness

“The accordion…”

Linguistic vs. Non-linguistic Givenness

“The accordion…”

Bard & Anderson, 1990; Clark & Marshall, 1981; Prince, 1992

CONCEPTUALIZATION STAGE

FORMULATION STAGE

CONCEPTUALIZATION STAGE

DISCOURSE STATUS(given vs. new)

(what speaker and listener both know)

FORMULATION STAGE

Joint Discourse Speaker-internal

Instruction-giving Task

Speaker

Approximately 12 feet

Listener

Experimental Paradigm

Speaker: “The accordion rotates right”

Speaker: “The toothbrush shrinks”

Speaker: “The belt expands”

Experiment 1: Priming Information

“The toothbrush;The belt;

The accordion”

Control Non-linguistic Linguistic

Joint Discourse Status predicts….

Activation-based predicts…

Reduced Duration of the Object Word

Linguistic

Non-linguistic

Control

360 370 380 390 400 410 420

Linguistic < Non-linguistic < Control

*

*

Activation-based Naturally Accounts For These Findings

Non-linguistic information led to reduction

Linguistic information led to more reduction

This task used predictability as a control to investigate givenness…

Predictability & Givenness

• A discourse status account predicts that givenness and topic continuity (i.e. predictability) pattern together, in the same representation

• By contrast, an activation-based model allows either predictability or givenness to lead to reduction.

Fowler & Housum, 1987; Prince 1981

Experiment 2: Target Given1/8 of trials

“The accordion”

Non-linguistic Linguistic

Experiment 2: Target New7/8 of trials

“The toothbrush”

Non-linguistic Linguistic

Reduced Duration of the Object WordTarget Given < Target New

*Linguistic

Non-linguistic

420 425 430 435 440 445 450 455 460

Target New

Target Given

Further Confirmation

• Even in the absence of strong predictability, speakers reduce in response to linguistic givenness information

• Exp.’s 1 & 2 suggest that speakers do not need to model discourse status explicitly for reduction

Speaker-internal Audience Design?

• Traditional views of discourse status say that speakers use it in part to model the listener (Clark & Marshall, 1981; Gundel et al., 1993)

• But if we do away with a representation of discourse status here, we should still ask whether speakers do it because of themselves or because of their listeners

Instruction-giving Task

Speaker

Listener

1) Blocked trials

2) Icon at the top of the screen

3) Headphones

v v

v v

Both

Speaker

Listener

None

405 410 415 420 425 430 435 440 445 450 455

Reduced Object Duration(Both, Speaker) < (Listener, None)

Speaker-internal Activation

• If speakers were tracking discourse status, they should have shown a different pattern of reduction

• Even without discourse status, speakers could have reduced for their listener, but did not

Summary of Results

• Linguistic givenness elicited more reduction than non-linguistic givenness in Experiment 1

• Linguistic givenness elicited reduction even without strong predictability in Experiment 2

• Speakers reduced when, and only when, they had givenness information in Experiment 3 (the listener doesn’t matter here)

CONCEPTUALIZATION

FORMULATION

Non-linguistic givenness created reduction

Linguistic givenness created more reduction

Givenness and predictability have separable effects, suggesting a common

substrate, namely activation.

Discourse Status Matters Elsewhere

• Word order (Arnold, Wasow, et al., 2000; Birner & Ward, 1994)

• Lexical choice (e.g. pronouns vs. more explicit expressions) (Ariel, 2000; Arnold, 1998; Gundel et al., 1993)

• Accenting (Pierrehumbert & Hirschberg, 1990)

Other Potential Models

• These results are still technically consistent with a model that includes an explicit representation of discourse status at the conceptual level.

• But we propose that our model is both more parsimonious and makes additional predictions, which we are currently testing

The Role of Audience Design

• Has effects on word choice, amount of detail, number of words (Arnold, Kahn & Pancani (CUNY Poster Thursday); Bard et al., 2000; Galati & Brennan 2010)

• The effect of audience design on reduction is mediated by the speaker’s internal representations (c.f. Balota, Boland & Shields, 1989; Bard et al., 2000)

The Role of Audience Design

Arnold, Kahn & Pancani, CUNY Poster Thursday

Take Home Message Slide

• Speakers reduce based on the state of their own internal representations– They don’t appear to need an explicit

representation of discourse status– They don’t appear to track the state of their

listener(s)

With Gratitude To…

• The Cognitive and Language groups at UNC for endless discussion, support, and critique

• Kellen Carpenter, Giulia Pancani, Alex Christodoulou, Alyssa Ventimiglia, Jennifer Tate, Sam Handel, and Leighanne McGill for help with these experiments

• And Ellen Bard, Scott Fraundorf, Florian Jaeger, Tuan Lam, Janet Pierrehumbert, and Joseph Tyler for useful discussions