The comparison of effectiveness and efficiency of distributed and massed trials instruction in teaching concepts to children with ASD

Discrete trial instruction is usually presented in three ways: massed trial instruction (MTI), distributed trial instruction (DTI) and task interspersal (TI). The aim of this research is to compare the efficacy and effectiveness of MTI and DTI in concept teaching to children with ASD. The participants of the study are four children with diagnosis of ASD and their ages range from 4-5 years. Experimental design of the study is adapted alternating treatments design which is one of the models of single-subject research. The total number of weekly trials set for the subject in the MTI was conducted one day a week. In DTI, the same number of trials for the subject was conducted in four instruction sessions with equal number of trials with MTI throughout four days of the week. All of the subjects reached the mastery criterion more quickly during DTI. The maintenance data was collected after 8, 9 and 10 weeks from the completion of the teaching sessions of the research. Considering this data, two of the subjects maintained the concepts. Social validity data collected from teachers who work with children in Developmental Support Unit in the university. This data shows that teachers have positive opinions about DTI. Key Words: Autism Spectrum Disorders, Discrete Trial Teaching, Massed Trial Instruction, Distributed Trial Instruction