to start as early as possible. Since parents can instruct incidental teaching, it could be beneficial to start in a natural home environment. McGee, Morrier, and Daly (1999) completed a study where the participants were toddlers instead of preschool-aged children, and there was a home-based component. The study included both a natural environment of a childcare center and the home of the child (McGee et al., 1999). The study consisted 28 children with ASD who participated in the program for at least months with more than thirty hours a week of planned early intervention through a combination of home based program and a center-based program (McGee et al., 1999). The parents had ten additional hours of hands-on training so they can implement the procedure at home. The study found that, by the time the children left the program to go to preschool, 82% of the toddlers with ASD were verbalizing meaningful words, so majority had functional language going into preschool (McGee et al., 1999).

Incidental teaching is a procedure that meets the needs for an inclusive group of toddlers and preschool aged children who have ASD and who are typically developed (McGee et al., 1999). Incidental teaching is a method that can use typical peers to aid the advancement of language and development with children who have ASD, but since it is in a more natural setting it diminishes the social barriers. In addition, it is a method that provides intensive instruction for children with ASD, but it also allows the children to be engaged in age-appropriate play with their peers (McGee et al., 1999). Hart and Risley (1975) discussed that peers in a naturalistic setting can also provide the instruction. This could not only aid the advancement of verbal skills with autistic children, but it could also promote social interaction.