Use and Misuse of Common Ground, a Complex Pragmatic Language Skill, in Adolescents with Autism Spectrum Disorder

Background:  Pragmatic language is a complex, multi-faceted domain that includes such diverse skill sets as reciprocal conversational skills (e.g., turn-taking), word choice based on specific conversational partners (e.g., register), and the comprehension and use of nonverbal aspects of communication that complement speech. Deficits in pragmatic language are essentially universal in individuals with autism spectrum disorder (ASD) and are often reported to be a significant source of social anxiety for these individuals. While pragmatic language has been the focus of significant research in ASD, many aspects of this complex domain have yet to be investigated at all. 

Objectives:  In this study, we use an experimental narrative task to study a specific pragmatic language skill, common ground, and its use in adolescents with and without ASD. Common ground refers to the tendency of interlocutors to modify how they communicate based on shared knowledge. This skill has not been specifically investigated in an ASD sample to date.

Methods:  Adolescents with ASD (n = 18) and typical development (TD; n = 18) were matched on chronological age, IQ, and receptive vocabulary. All participants had IQ scores in the average range. For the experimental task, participants told stories based on cartoon stimuli to a listener. The existence of common ground was experimentally manipulated such that participants told stories in one of two conditions: (A) the private condition, in which information about the cartoon was known only to the participant, thus the listener and participant had no common ground and (B) the shared condition, in which the listener and participant shared knowledge about the cartoon and thus had common ground. Three narratives were told in each condition, for a total of six narratives per participant. Story word count was the primary dependent measure.

Results:  Consistent with prior research, TD participants produced reliably shorter narrations when they shared knowledge with an interlocutor, an effect not observed in participants with ASD (Group X Condition interaction: F(1,34) = 5.31, p = .03, partial h² = 0.14). This effect was unrelated to general skills such as IQ or receptive vocabulary. In the ASD group, the effect was correlated with age, and with symptom severity: younger and more severely affected participants showed little evidence of common ground, while older, more socially skilled participant appeared to demonstrate the skill. Qualitative data suggested that participants with ASD were attempting to use common ground, but were not consistently successful in doing so.

Conclusions:  Adolescents with ASD were attempting to use common ground but had not yet developed the subtle, implicit approach of their TD peers. Results suggest essentially stable abilities for TD adolescents, while adolescents with ASD show delays, and emerging skills, in this important pragmatic domain. These findings highlight the need for continued intervention targeting discourse skills into adolescence, and suggest that adolescents with ASD may be particularly open to change in this domain.