Effects of system of least prompts on increasing frequency and diversity of pretend play in children with autism spectrum disorder (ASD)

The purpose of this study is to investigate the effects of system of least prompts with the use of contingent imitation on increasing frequency and diversity of pretend play in children with autism spectrum disorder (ASD). Also, social validity data regarding the study were collected from the mothers and teachers of all children. Three children with ASD aged between 5-6 took part in the study. Functional relationship was established by using multiple probe design across sets. The findings showed that system of least prompts was effective on increasing frequency, categorical diversity of pretend play as well as vocalizations for all children. Furthermore, it was seen that diversity among pretend play behaviors and vocalizations also increased. More importantly, novel pretend play behaviors and vocalizations by all children increased, the rate of which changed among toy sets. The findings also indicated that system of least prompts was effective on increasing the number of pretense sequences. In the study, it was seen that all children maintained target skills across sessions one, two and four weeks after the intervention was completed. Furthermore, all children generalized targeted behaviors across different setting, person and toys. Social validity findings showed that opinions of mothers and teachers of all children regarding the study were positive. Keywords: Autism spectrum disorder, pretend play, system of least prompts, least to most prompting, contingent imitation.