Using disfluency to understand, um, sentences . . . with PP-attachment ambiguities

Jennifer E. Arnold and Kellen Carpenter, UNC Chapel Hill

Background1) Prosody (e.g., pausing, acoustic prominence) marks some aspect of the speaker’s intended message:

• syntactic structure (e.g., Snedeker & Trueswell, 2003)• discourse status (e.g., Brown, 1983; Watson & Arnold, 2005)• contrast (Terken & Hirschberg, 1994)• focus structure (Selkirk, 1996)

2) Pausing, word duration, and acoustic prominence also reflect processing constraints on production:

• Disfluency correlates with longer words (Bell et al., 2003)• Difficult reference induces longer words and higher pitch (Christodoulou & Arnold, 2008) • Predictability and givenness correlate with prominence, and also can facilitate production (e.g., Bell et al., 2009; Kahn & Arnold, CUNY 2010 poster; Watson et al., 2008)

Prosodic cues are ambiguous (cf. Ferreira, 2007; Clifton et al., 2006). E.g., how do listeners know whether a pause signals processing or a syntactic break?

Funded by NSF

grant BCS-0745627

References Bell, A., et al. (2003). Effects of disfluencies, predictability, and utterance position on word form variation in English conversation. JASA, 113, 1001-1024. Bell, A., et al. (2009). Predictability effects on durations of content and function words in conversational English. JML, 60, 92-111.Christodoulou, A., & Arnold, J. E. (2008). Acoustic prominence as a result of production difficulty. Prosody Poster; Ithaca, NY.Clifton, C., Carlson, K., & Frazier, L. (2006). Tracking the what and why of speakers choices: Prosodic boundaries and the length of constituents PBR, 13, 854-981.Ferreira, F. (2007). Prosody and performance. LCP, 22, 1151-1177.Kahn, J., & Arnold, J. E. (2010). When Predictability is Not Enough: The Additional Contribution of Givenness to Durational Reduction. CUNY Poster; New York City, NY. Snedeker, J., & Trueswell, J. C. (2003). Using Prosody to Avoid Ambiguity: Effects of Speaker Awareness and Referential Context. JML, 48, 103-130Snedeker, J., & Trueswell, J. C. (2004). The developing constraints on parsing decisions…. Cog.Psych, 49,238-299.Selkirk, E. O. (1996). Sentence prosody: Intonation, stress and phrasing. In J. A. Goldsmith (Ed.), The handbook of phonological theory. Cambridge, Mass., USA: Blackwell.Terken, J., & Hirschberg, J. (1994). Deaccentuation of words representing given information…. Language and Speech, 37, 125-145.Watson, D. & Gibson, E. (2004). The relationship between intonational phrasing and syntactic structure in language production. LCP, 19, 713-755.Watson, D., Arnold, J.E., & Tanenhaus, M. K. (2008). Tic tac TOE: Effects of predictability and importance on acoustic prominence…. Cognition, 106, 1548-1557.Watson, D., & Arnold, J. E. (2005). Not just given and new: The effects of discourse and task-based constraints on acoustic prominence. CUNY Poster; Tuscon, AZ.

Research QuestionWhen listeners think that a pause might result from production difficulty, are they less likely to use it as a cue to syntactic structure?

FLUENT: Tickle the meerkat [pause] with the feather.

DISFLUENT: Tickle theee uh… meerkat [pause] with the feather.

A pause usually signals VP-attachment

In the presence of disfluency, is the NP attachment interpretation more available?

Model: multilevel logistic regression (SAS proc glimmix)

Cross-classified; subjects and items random effectsDependent variable: Instrument vs. Modifier interpretationPredictors: Control variables (all n.s.)

• Fluency (n.s.) • Verb bias• Pause (n.s.) • Instrument picture on left side• Fluency x Pause (Est=.89; p = .04) • List

• forwards/ backwards

Results: % Instrumental chosen

FLUENT / PAUSE: Bunny looked at the table [pause] with the magnifying glass

FLUENT / NO PAUSE: Bunny looked at the table with the magnifying glass

DISFLUENT / PAUSE: Bunny looked at thee uh table [pause] with the magnifying glass

DISFLUENT / NO PAUSE: Bunny looked at thee uh table with the magnifying glass

69%

79%

66%

65%

EXPERIMENT 1:Which picture best matches the sentence?

Kitty scratched the puppy with the paper Bunny looked at the table with the magnifying glass.

Doggy threw the flower with the cup Birdy sang to the owl with the funnel.

Sentences based on Snedeker & Trueswell (2004), normed for verb bias

EXPERIMENT 2: Eyetracking (in progress)

•Fluent/no pause/destination: Put the meerkat on the circle on the left.•Fluent/no pause/modifier: Put the meerkat on the circle [pause] on the triangle.

•Fluent/pause/destination: Put the meerkat [pause] on the circle on the left.•Fluent/pause/modifier: Put the meerkat [pause] on the circle [pause] on the triangle.

•Disfluent/pause/destination: Put thee uh meerkat [pause] on the circle on the left. •Disfluent/pause/modifier: Put thee uh meerkat [pause] on the circle [pause] on the triangle.

Task: Get all the animals to their “home” on one of the shapes

Predict:

• More looks to the empty circle during fluent/pause than either of the other conditions

• Faster responses to the destination interpretation conditions for the fluent/no pause and disfluent/pause conditions; faster modifier responses in the fluent/pause condition

This pause is manipulatedThis pause is part of the modifier disambiguation

Conclusions• For fluent items: Pause promotes instrument (VP-attachment) interpretations • This effect disappears for disfluent items• The interaction suggests disfluency affects the interpretation of the pause

• If disfluency just created a bias toward the modified-NP structure (in which the NP is relatively more complex), we would expect a main effect of disfluency and no interaction

• Listeners may attribute the pause to difficulty, which reduces the informativeness of the pause for syntactic structure

MaterialsFLUENT / PAUSE: Bunny looked at the table [pause] with …

FLUENT / NO PAUSE: Bunny looked at the table with …

DISFLUENT / PAUSE: Bunny looked at thee uh table [pause] with…

DISFLUENT / NO PAUSE: Bunny looked at thee uh table with …

Disfluent items:The effect of the pause should be diminished or

eliminated

Fluent items:Predict more VP-attach for

pause than no-pause condition

*stimuli are fully cross-spliced