The development of turn-taking skills in typical development and autism

Background: The ability to smoothly engage one’s interlocutor - contributing at the right time, without too much overlapping, nor long pauses - is an important component in conversations and social interactions. Different components have been proposed as crucial for smooth child-caregiver turn-taking: linguistic, socio-cognitive and motor development, as well as interpersonal adjustment. Slower turn-taking has been observed in autism spectrum disorder (ASD) where these components are often atypical. A recent meta-analysis identifies no reliable changes in turn-taking as children develop, and slower turn-taking in children with ASD. However, several shortcomings in the current literature are highlighted: use of aggregated data, different methods for handling instances of overlapping speech, cross-sectional studies, and insufficient focus on possible confounds. In other words, current evidence on how turn taking abilities develop in children with and without autism is inconclusive.Goals: We aim to empirically evaluate the above meta-analytic findings with more rigorous methods. We extend the state-of-the-art by assessing the relation of individual differences in linguistic, socio-cognitive and motor development in turn-taking. We finally assess the role of interpersonal adjustment on a turn-by-turn basis stratifying by self-adjustment, and how adjustment is moderated by individual differences in development.Methods: We analyzed spontaneous speech in 64 parent-child dyads from a longitudinal corpus (30 minutes of play activities at 6 visits over 2 years). We included 32 children diagnosed with ASD and 32 linguistically matched typically developing (TD) children (mean age at recruitment respectively 32.76 and 20.27 months). Multilevel Bayesian ex-Gaussian regressions are used to model response latencies in turn-taking. Analyses of individual differences include Mean Length of Utterance (MLU) as proxy for linguistic skills, Vineland Socialization and Motor Skills. Turn-by-turn conversational dynamics are modeled in terms of concurrent self-adjustment (intrapersonal autocorrelation of latencies) and interpersonal adjustment, within multilevel models.Results: Children with ASD responded faster on average than typically developing ones (116ms, 95%CIs 95-136 vs 307ms, 95%CIs 290-325, evidence ratio for the difference, ER: 24), due to higher speech overlapping (no group difference when overlapping is removed). Both groups decreased latency with development (children with ASD by 78ms, 95%CIs 54-102, every 4 months, TD 47ms, 95%CIs 30-64).Response latency was reliably related to socialization, linguistic and motor skills, which explain variance better than just time from first visit. Children and caregivers displayed positive self- and interpersonal adjustment in both groups (e.g., slower than average turns are followed by slower turns); both effects persisted across 3-5 turns, creating joint “waves” of slower and then faster sequences of turns. Conclusions: We revise and extend previous meta-analytic findings. Children with ASD respond faster than typically developing ones, due to speech overlaps. Turn-taking abilities develop in relation to individual differences in linguistic, social, and motor skills, but both groups displayed similar self-adjustment and adaptation to others.