Acoustic marking of prominence: how do preadolescent speakers with and without high-functioning autism mark contrast in an interactive task?

Abstract

The acoustic correlates of discourse prominence have garnered much interest in recent adult psycholinguistics work, and the relative contributions of amplitude, duration and pitch to prominence have also been explored in research with young children. In this study, we bridge these two age groups by examining whether specific acoustic features are related to the discourse function of marking contrastive stress by preadolescent speakers, via speech obtained in a referential communication task that presented situations of explicit referential contrast. In addition, we broach the question of listener-oriented versus speaker-internal factors in the production of contrastive stress by examining both speakers who are developing typically and those with high-functioning autism (HFA). Diverging from conventional expectations and early reports, we found that speakers with HFA, like their typically developing peers (TYP), appropriately marked prominence in the expected location, on the pre-nominal adjective, in instructions such as “Pick up the BIG cup”. With respect to the use of specific acoustic features, both groups of speakers employed amplitude and duration to mark the contrastive element, whereas pitch was not produced selectively to mark contrast by either group. However, the groups also differed in their relative reliance on acoustic features, with HFA speakers relying less consistently on amplitude than TYP speakers, and TYP speakers relying less consistently on duration than HFA speakers. In summary, the production of contrastive stress was found to be globally similar across groups, with fine-grained differences in the acoustic features employed to do so. These findings are discussed within a developmental framework of the production of acoustic features for marking discourse prominence, and with respect to the variations among speakers with autism spectrum disorders that may lead to appropriate production of contrastive stress.

Keywords:

• contrastive stress production
• high-functioning autism
• acoustic prominence
• discourse

Acknowledgements

We are grateful to Josh Diehl and Duane Watson for sharing their PRAAT scripts for acoustic analysis, to the participating families for their involvement in the study, and for McGill University's Faculty of Medicine research bursary awards to Shaw for funding of this project. Versions of this study were presented at the International Meeting for Autism Research in 2010 and at Experimental and Theoretical Approaches to Prosody-2 in 2011.