Using prosody to avoid ambiguity: Effects of speaker awareness and referential context

In three experiments, a referential communication task was used to determine the conditions under which speakers produce and listeners use prosodic cues to distinguish alternative meanings of a syntactically ambiguous phrase. Analyses of the actions and utterances from Experiments I and 2 indicated that Speakers chose to produce effective prosodic cues to disambiguation only when the referential scene provided support for both interpretations of the phrase. In Experiment 3, on-line measures of parsing commitments were obtained by recording the Listener's eye movements to objects as the Speaker gave the instructions. Results supported the previous experiments but also showed that the Speaker's prosody affected the Listener's interpretation prior to the onset of the ambiguous phrase, thus demonstrating that prosodic cues not only influence initial parsing but can also be used to predict material which has yet to be spoken. The findings suggest that informative prosodic cues depend upon speakers' knowledge of the situation: speakers provide prosodic cues when needed; listeners use these prosodic cues when present. (C) 2002 Elsevier Science (USA). All rights reserved.