Turn-timing in conversations between autistic adults: Typical short-gap transitions are preferred, but not achieved instantly

PLOS ONE RESEARCH ARTICLE Turn-timing in conversations between autistic adults: Typical short-gap transitions are preferred, but not achieved instantly Simon Wehrle ID1*, Francesco Cangemi1, Alicia Janz1, Kai Vogeley2,3, Martine Grice1 1 Institut für Linguistik-Phonetik, University of Cologne, Cologne, Germany, 2 Department of Psychiatry, University Hospital Cologne, Medical Faculty, University of Cologne, Cologne, Germany, 3 Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Center Jülich, Jülich, Germany a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Wehrle S, Cangemi F, Janz A, Vogeley K, Grice M (2023) Turn-timing in conversations between autistic adults: Typical short-gap transitions are preferred, but not achieved instantly. PLoS ONE 18(4): e0284029. https://doi.org/ 10.1371/journal.pone.0284029 Editor: Leonardo Lancia, Universite Sorbonne Nouvelle Paris 3, FRANCE Received: September 28, 2022 Accepted: March 22, 2023 Published: April 6, 2023 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0284029 Copyright: © 2023 Wehrle et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All data and scripts are available in the OSF repository at https://osf.io/ v5pn4/. The data folder contains one csv file with the experimental data and one csv file with subject * Abstract The organisation of who speaks when in conversation is perhaps the most fundamental aspect of human communication. Research on a wide variety of groups of speakers has revealed a seemingly universal preference for between-speaker transitions consisting of very short silent gaps. Previous research on conversational turn-taking in Autism Spectrum Disorder (ASD) consists of only a handful of studies, most of which are limited in scope and based on the non-spontaneous speech of children and adolescents. No previous studies have investigated dialogues between autistic adults. We analysed the conversational turntaking behaviour of 28 adult native German speakers in two groups of dyads, in which both interlocutors either did or did not have a diagnosis of ASD. We found no clear difference in turn-timing between the ASD and the control group overall, with both groups showing the same preference for very short silent-gap transitions that has been described for many other groups of speakers in the past. We did, however, find a clear difference between groups specifically in the earliest stages of dialogue, where ASD dyads produced considerably longer silent gaps than controls. We discuss our findings in the context of the previous literature, the implications of diverging behaviour specifically in the early stages of conversation, and the general importance of studying the neglected aspect of interactions between autistic adults. 1. Introduction Turn-taking is in essence a form of cooperative interaction. Humans engage in many temporally coordinated collaborative activities besides spoken interaction, such as manual labor, dancing or music-making (see e.g. [1]). Similarly, communicative turn-taking, in either the vocal or gestural modality, is not limited to humans. Many different species from different taxa perform tightly synchronised and regulated communicative interactions (e.g. [2]). Human turn-taking in conversation, however, is a unique and remarkable phenomenon. It is not only executed with split-second precision and flexibility and involves the parallel PLOS ONE | https://doi.org/10.1371/journal.pone.0284029 April 6, 2023 1 / 22 PLOS ONE data. The main folder contains an RMarkdown file (in .rmd and .html formats) in which the entire paper is reproduced with code chunks that were used to produce all plots and perform all modelling adjacent to the relevant portions of the paper. Funding: Funding was provided by the Deutsche Forschungsgemeinschaft (CRC1252 Prominence in Language, Project A02) to MG and KV (http:// www.dfg.de) and by the Studienstiftung des Deutschen Volkes (Promotionsstipendium) to SW (http://www.studienstiftung.de). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Turn-timing in conversations between autistic adults prediction, planning and production of utterances which are improvised yet rich with meaning, but it is also the key means through which human language, and to a considerable extent human culture, are learned and transmitted (cf. [3]). Most turns in spoken conversation are short and most transitions between turns consist of very short gaps between speakers [4], which are preferred to other possible kinds of transition such as longer gaps or overlaps (two speakers talking at once). A modal value of around 200 milliseconds of silence between speakers has been shown for a wide range of languages and speakers, with only minor language-specific variations [5–8]. As successful and rapid turn-timing crucially relies on socio-communicative abilities such as pragmatic language skills [4, 9, 10], which are typically thought to be impaired in individuals on the autism spectrum, delayed or otherwise divergent patterns of turn-timing in this population might plausibly be predicted. However, there is only very limited quantitative research on turn-timing in Autism Spectrum Disorder (ASD) to date, and none whatsoever on turn-timing in conversations between autistic adults. The limited experimental evidence available seems to point to a general tendency for longer silent gaps in conversations involving autistic participants (see Section 4.2), although it is not clear to which extent this trend can be expected to apply to (semi-)spontaneous conversations between autistic adults, which are investigated in this study for the first time. We present an analysis of turn-taking strategies in pairs of German adults, where both interlocutors either did or did not have a diagnosis of ASD (in so-called disposition-matched dyads). When considering the dialogue as a whole, we found no clear differences in turn-timing between the ASD and the control (CTR) group. However, closer inspection reveals that, compared to CTR dyads, autistic dyads produced longer gaps between turns specifically in the earliest stages of dialogue. We discuss the implications of these results and relate them to previous research on autism and to the notion of seemingly universal patterns of turn-timing in spoken dialogu (...truncated)