A core symptom in autism spectrum disorders (ASD) is difficulty with social communication. Joint attention, or spontaneously directing others' attention to something of interest, is a key aspect of social communication, and individuals with ASD may not engage in this social behavior as easily as typically-developing individuals. This project will compare the effectiveness of 3 different types of discrete trial training (traditional vs. mastery-interspersed vs. incidental) in terms of speed of acquisition and strength of generalization of joint attention in children with autism. The initial phase of the project will be limited to 9 participants and 9 additional participants will be added during each subsequent phase. The dependent measures include scores on standardized tests administered pre and post-intervention, the percent of correct responses per session and number of trials and sessions required to reach the mastery criteria during the acquisition and generalization phases. At the completion of the second phase of this study (n = 18), a preliminary analysis relating the effectiveness of each type of discrete trial to participant characteristics (test scores and measures of joint attention) will be done in order to address the question of relative effectiveness of trial types.