Comparison of task interspersal ratios on efficiency of learning and problem behavior for children with autism spectrum disorder

Four kids with autism learned new tasks in four different lesson mixes. The mixes were 3 mastered to 1 new, 1 to 1, 1 mastered to 3 new, and 0 mastered to 1 new.

Each child got all four mixes in random order. The team counted how many trials each child needed to master the new skill and watched for problem behavior.

The 0:1 mix—only new tasks—won for every child. They reached mastery in the fewest trials.

Adding old tasks did not cut problem behavior. Kids acted the same no matter the mix.

Rapp et al. (2016) said task interspersal might help, but warned the proof was thin. Knutson now gives that proof—interspersal slowed learning.

Glodowski et al. (2020) also used an alternating-treatments design with autistic kids. They compared token setups, not task mixes, yet both studies show one clear winner after quick side-by-side tests.

Fulton et al. (2020) looked at break size, not task mix, but again found that leaner schedules can work fine. Together these papers say: test your ratios; leaner can be faster.

Stop sprinkling old tasks into lessons for kids with autism. Run new items back-to-back until mastery. You will save trials and free up time for more goals. Track problem behavior—if it stays flat, you lose nothing by dropping the fluff.