The study will utilize a multiple baseline design to assess a sibling mediated play intervention using Behavior Skills Training (BST) to increase joint engagement (JE) and symbolic play (SP) behaviors in children with autism spectrum disorder (ASD). JE will be operationalized as turn-taking, imitation, or following through on verbal commands to play. SP will be operationalized as play actions with objects for imaginative uses, without the actual objects present, or labeling abstract properties of the object. Six siblings of children with ASD will be taught BST during playtime. JE and SP occurrences will be scored via a 15 second partial interval procedure for 5-minute play sessions. It is predicted that after intervention, children with ASD would exhibit more instances of JE and SP play than in baseline
