Backchannels in conversations between autistic adults are less frequent and less diverse prosodically and lexically

Abstract Backchannels (BCs; listener signals such as ‘mmhm’ or ‘okay’) are a ubiquitous and essential feature of spoken interaction. They used by listeners predominantly to support the ongoing turn their interlocutor signal understanding agreement. Listeners seem be highly sensitive exact realisations BCs judge deviations from typical forms negative. Very little is known about use speakers diagnosed with autism spectrum disorder (ASD). In dialogue recordings 28 German adults in two groups disposition-matched dyads (i.e., both interlocutors were either autistic non-autistic), we found that ASD group was characterised (1) lower rate per minute (particularly early stages conversation), (2) less diversity lexical realisation (3) diverse flexible mapping different intonation contours BC types. We interpret these results reflecting more general characteristics compared non-autistic individuals, namely strategies signalling attention towards an behaviour social