In the past, research has suggested that autistic people are not able to communicate well with non-autistic people because of autistic people's communication difficulties. However, newer theories question this conclusion. It is now thought that the communication difficulties may be because autistic and non-autistic people both struggle to understand each other. This study explores how these differences in shared understanding relate to autistic people's mental well-being, confidence in social situations and social identities (groups that we belong to and that influence how we see ourselves). We created an online survey taken by 512 autistic adults, which included questions about their confidence being social with people from different groups (such as other autistic people or people they share a hobby with), about the social groups they felt they belong to and about their mental well-being. First, participants reported higher social confidence when interacting with members of a social group they belonged to. Second, being confident during these interactions was linked to higher mental well-being. Finally, the groups participants belonged to did not influence the link between social confidence and mental well-being. These findings are important as they help us better understand autistic people's experiences of social interactions and what contributes to good and poor mental well-being in autistic people. They also help us to think further about how to improve autistic people's well-being.
Keywords: adults; autism; double empathy; homophily; mental well-being; social identity; social self-efficacy.