Listeners use intonational phrase boundaries to project turn ends in spoken interaction

Abstract

In conversation, turn transitions between speakers often occur smoothly, usually within a time window of a few hundred milliseconds. It has been argued, on the basis of a button-press experiment [De Ruiter, J. P., Mitterer, H., & Enfield, N. J. (2006). Projecting the end of a speaker's turn: A cognitive cornerstone of conversation. Language, 82(3):515–535], that participants in conversation rely mainly on lexico-syntactic information when timing and producing their turns, and that they do not need to make use of intonational cues to achieve smooth transitions and avoid overlaps. In contrast to this view, but in line with previous observational studies, our results from a dialogue task and a button-press task involving questions and answers indicate that the identification of the end of intonational phrases is necessary for smooth turn-taking. In both tasks, participants never responded to questions (i.e., gave an answer or pressed a button to indicate a turn end) at turn-internal points of syntactic completion in the absence of an intonational phrase boundary. Moreover, in the button-press task, they often pressed the button at the same point of syntactic completion when the final word of an intonational phrase was cross-spliced at that location. Furthermore, truncated stimuli ending in a syntactic completion point but lacking an intonational phrase boundary led to significantly delayed button presses. In light of these results, we argue that earlier claims that intonation is not necessary for correct turn-end projection are misguided, and that research on turn-taking should continue to consider intonation as a source of turn-end cues along with other linguistic and communicative phenomena

The development of children’s ability to track and predict turn structure in conversation

“…Overall, participants made few anticipatory switches after non-questions, even in the English videos when they had full linguistic access. Prior work using online, metalinguistic tasks has shown that participants can use linguistic cues to accurately predict upcoming turn ends (Bögels & Torreira, 2015;Magyari & De Ruiter, 2012;De Ruiter et al, 2006). The current results add a new dimension to our understanding of how listeners make predictions about turn ends: both children and adults spontaneously monitor the linguistic structure of unfolding turns for cues to imminent responses.…”

“…Prior work with adults has found a consistent role for lexicosyntax in predicting upcoming turn structure (De Ruiter et al, 2006;Magyari & De Ruiter, 2012), whereas the role of prosody is still under debate (Duncan, 1972;Ford & Thompson, 1996;Bögels & Torreira, 2015). Knowing that children comprehend more about prosody than lexicosyntax early on (see Speer & Ito (2009) for a review), we thought it possible that young children would instead show an advantage for prosody in their predictions about turn structure in conversation.…”

“…Even in adults, Bögels and Torreira (2015) showed that the trade-off in informativity between lexical and prosodic cues is more subtle in semi-natural speech. The present findings are the first to show evidence of a similar effect developmentally.…”

“…Lexical, syntactic, and prosodic information (e.g., wh-words, subject-auxiliary inversion, and list intonation) can all inform addressees about upcoming linguistic structure (De Ruiter, Mitterer, & Enfield, 2006;Duncan, 1972;Ford & Thompson, 1996;Bögels & Torreira, 2015). Non-verbal cues (e.g., gaze, posture, and pointing) often appear at turn-boundaries and can sometimes act as late indicators of an upcoming speaker switch (Rossano, Brown, & Levinson, 2009;Stivers & Rossano, 2010).…”

“…Prosody is tied closely to the syntax of an utterance, so the two linguistic signals are difficult to control independently (Ford & Thompson, 1996). Bögels and Torreira (2015) used a combination of button-press and verbal responses to investigate the relationship between lexicosyntactic and prosodic cues in turn-end prediction. Critically, their stimuli were cross-spliced so that each item had full prosodic cues to accompany the lexicosyntax.…”