Time Contingency and Social Engagement Shape Interaction Choices in Autism and Neurotypical Development

In social interactions, the coordination of biobehavioural rhythms – interpersonal synchrony (IS) – fosters cooperation, enhances prosocial behaviours, and moulds lifelong social attitudes. At the core of synchronous interactions is the ability to detect and respond contingently to communicative signals. Atypicalities in these processes may contribute to socio-communicative difficulties commonly observed in Autism Spectrum Disorder (ASD), where social disconnection is often reported. Our research simulates interactions to delve into factors influencing IS in ASD and their neurotypical (TD) peers, examining the impact of time contingency and social engagement on preferences for social partners. Using a tablet-based task n=116 participants (n=58 ASD, n=58 TD) repeatedly interacted with faces that transitioned from side to front. These varied in time contingency (immediate or delayed response) and social engagement (smiley direct gaze vs neutral averted gaze). Before and after interaction participants ranked faces by preference. We found that while both groups preferred stimuli that were timely and engaging, neurotypical participants compensated for disrupted time contingency with social engagement, a pattern not observed in the autistic sample. We argue that the combination of time contingency and social engagement enhances social agency, which is particularly relevant for ASD. We discuss how creating predictable and engaging social environments could help autistic individuals feeling more connected in social settings.