Smiling synchronization predicts interaction enjoyment in peer dyads of autistic and neurotypical youth
Authors: McNaughton Kathryn A , Moss Alexandra , Yarger Heather A , Redcay Elizabeth 
Published: March 2024

Autistic youth often experience challenges in interactions with neurotypical peers. One factor that may influence successful interactions with peers is interpersonal synchrony, or the degree to which interacting individuals align their behaviors (e.g. facial expressions) over time. Autistic and neurotypical youth were paired together into three dyad types: autistic participants paired with autistic participants (AUT-AUT), autistic participants paired with neurotypical participants (AUT-NT), and neurotypical participants with neurotypical participants (NT-NT). Dyads participated in a free conversation task and a video-watching task. We tested whether smiling synchronization differed between AUT-AUT, AUT-NT, and NT-NT dyads. We further tested if smiling synchronization predicted youth-reported interaction enjoyment. AUT-NT dyads had significantly reduced smiling synchronization compared with NT-NT dyads. Smiling synchronization also predicted multiple aspects of participant-rated interaction enjoyment, such as the desire to interact with the peer partner again, above and beyond the overall amount of smiling in the interaction. These findings indicate links between smiling synchronization and interaction enjoyment for autistic and neurotypical youth. Identifying opportunities to synchronize or share positive affect in interactions may promote more enjoyable interactions for both autistic and neurotypical youth. Lay abstract For autistic and neurotypical youth, having positive social interactions with other youth is an important part of well-being. Other researchers have found that one factor that can make people feel like social interactions have gone well is synchronization. Synchronization happens when peoples’ body movements and facial expressions align while they’re interacting. We focus on smiling synchronization here because other studies have found that when neurotypical individuals synchronize their smiles more in a social interaction, they say they enjoy that social interaction more. However, no studies have directly tested whether smiling synchrony influences social interaction enjoyment in autistic and neurotypical youth. We measured smiling synchrony in pairs of interacting autistic and neurotypical youth who were meeting each other for the first time. Some pairs were autistic youth interacting with other autistic youth (autistic with autistic participant pairs), some pairs were autistic youth interacting with neurotypical youth (autistic with neurotypical participant pairs), and other pairs were neurotypical youth interacting with neurotypical youth (neurotypical with neurotypical participant pairs). We found that autistic with neurotypical participant pairs had lower smiling synchrony than neurotypical with neurotypical participant pairs. Youth who were in dyads that had more smiling synchrony said they enjoyed interacting with their partner more and that they wanted to interact with their partner again. Our research shows that smiling synchrony is one part of interactions between autistic and neurotypical youth that influences how well youth say the interaction went. Identifying natural opportunities for autistic and neurotypical youth to share positive feelings could be one way to promote positive social interactions between autistic and neurotypical youth.