The art of common ground: emergence of a complex pragmatic language skill in adolescents with autism spectrum disorders.

Deficits in pragmatic language are central to autism spectrum disorder (ASD). Here we investigate common ground, a pragmatic language skill in which speakers adjust the contents of their speech based on their interlocutor's perceived knowledge, in adolescents with ASD and typical development (TD), using an experimental narrative paradigm. Consistent with prior research, TD participants produced shorter narrations when they shared knowledge with an interlocutor, an effect not observed at the group level in ASD. This effect was unrelated to general skills such as IQ or receptive vocabulary. In ASD, the effect was correlated with age and symptom severity: older and less severely affected participants did shorten their narratives. Several metrics (including explicit references to common ground, speech disfluencies, and communicative quality ratings) suggested that, although adolescents with ASD did not show implicit reductions in their narrative length, they were aware of common ground, and communicated differently in its presence.