Do perceptual timing mechanisms underlie attenuated behavioral IPS in autism?

Interpersonal synchrony (IPS) mediates natural interactions and rapport. Attenuated IPS has been shown between autistic individuals and their interaction partners; however, the mechanisms of this attenuation remain unclear. One possibility could lie in differences perceiving the timing of others’ behaviors. The present study therefore aimed to relate the behavioral production of IPS with the perception of IPS and of temporal event-structure coding in autistic and non-autistic individuals. Autistic and non-autistic participants engaged in naturalistic conversations with a non-autistic stranger, who was naïve to the participant’s diagnostic status. Participants reported their experiences of perceived synchrony with the partner. Behavioral IPS was computed using automatic video-based analysis. A perceptual simultaneity task measured the perception of temporal event-structure in a nonsocial context. Bayesian linear mixed models were used to evaluate the effects of perceived IPS and temporal event-structure coding, amongst additional covariates, on behavioral IPS. Expectedly, the behavioral IPS was reduced for dyads including an autistic individual. Neither perceived IPS, nor temporal event-structure coding, were associated with reduced behavioral IPS for dyads with and without an autistic individual. These findings hint that attenuated behavioral IPS may not result from atypical perception of the timing of others’ behaviors. We speculate on other social cognitive mechanisms that could underlie attenuated behavioral IPS that is often observed in interactions including autistic individuals.