ABSTRACT
When teaching discriminations, clinicians may choose to teach one target at a time, repeatedly, until mastery (blocked-trial instruction), or they may choose to teach multiple targets, interspersed, simultaneously (mixed-trial instruction). Historically, it was recommended clinicians use mixed-trial instruction at the onset of teaching as blocked-trial instruction may produce faulty stimulus control. However, a recent study demonstrated that a modified blocked-trial instructional arrangement was more efficient than mixed-trial instruction and block-size fading was unnecessary to maintain discriminated performance in adults with intellectual and developmental disabilities. The generality of these results to early learners is unknown. This study extended the aforementioned research to early learners diagnosed with autism spectrum disorder. Using an adapted alternating treatment design, we compared the rate of acquisition with both instructional formats across two foundational early learner skills. Comparable learning across both formats for all four early learners was observed.