Mechanisms of Altered Imitation in Autism Spectrum Disorders.

Imitation plays a critical role in enhancing social reciprocity and social/non-social skill learning. Accordingly, impaired imitation may have downstream implications on skill acquisition in autism. Social, motor, representational, and executive processes contribute to imitation performance, but it is unknown the degree to which differences in these domains contribute to imitation differences in autism. In the present study, we evaluated the role of various psychological mechanisms of autism-related imitation differences using mediation models. We assessed autistic and non-autistic 7-12-year-old children (n = 708) with FSIQ ≥ 80, using a wide battery of performance-based and parent-report tests that measured meaningful and non-meaningful gesture imitation performance, motor execution, action representation, social motivation, and executive function processes. Multiple marginal mediation analyses revealed that motor execution tests most strongly mediated imitation deficits in autism, though effects from social motivation, action representation, and executive function also partially mediated the relationship between autism diagnosis and imitation performance. Using cross-validated regression models, the domains tested here accounted for 39% of the variation in imitation performance. Results are contextualized across a broad range of experimental and observational studies with respect to the prompted imitation task utilized here. Future research will require longitudinal data, particularly from earlier stages of development.