2. Methods
2.1. Participants
Twelve children (11 males, 1 female) with a diagnosis of autism were included in the study. The diagnosis was
determined by pediatricians and/or psychologists based on criteria listed in the 4th ed. of the Diagnostic and Statistical
Manual of Mental Disorders (DSM-IV; American Psychiatric Association, 2000). None of the children presented with any other
diagnosis, including intellectual disability. The children were between the ages of 47 and 78 months and resided at home in
either the United States or the United Kingdom. All participants were selected from families who had participated in an
initial SRP parent-training course offered at the Autism Treatment Center in Sheffield, Massachusetts, which provided
parents with an overview of basic SRP principles, but none of the children had received any SRP intervention prior to the
study. Six of these families, whose children met our inclusionary and exclusionary criteria, were enrolled in the SRP intensive