| This study explored how the Picture Exchange Communication System (PECS) impacts social skills in children aged 7 to 10 years with autism spectrum disorder (ASD). Using a single-case experimental design (A-B-C), four children with ASD were selected through convenience sampling from a rehabilitation center in Tehran. Their cognitive and social skills were assessed with Raven’s Colored Progressive Matrices (RCPM) and the Autism Social Skills Profile (ASSP), respectively. Each child participated in twelve individual PECS sessions, each lasting 45 minutes. After the intervention, assessments were repeated with the ASSP, and follow-up evaluations were conducted one month later. Data analysis included visual analysis, recovery percentages, and Cohen’s D effect size, using SPSS version 24. Results showed significant improvements in social skills due to PECS, with instructor-reported effect sizes of 1.6, 1.4, 1.2, and 1.6. Notably, gains were observed in social reciprocity (effect sizes: 1.4, 1.08, 0.98, 1.6) and social participation (effect sizes: 1.91, 1.77, 1.56, 1.73), while detrimental social behaviors decreased (effect sizes: 1.07, 1.1, 1.4, 1.2). Parental reports confirmed these improvements, highlighting enhanced social skills and fewer negative behaviors. Overall, the study suggests that PECS is an effective tool for improving social skills and reducing problematic behaviors in children with ASD, supporting their vital social development. |