The effects of interspersal training versus high-density reinforcement on spelling acquisition and retention.
For kids with ID, blending mastered spelling words with new ones beats loading up on extra reinforcement.
01Research in Context
What this study did
Researchers compared two ways to teach spelling to kids with intellectual disability. One group got interspersal training: every new word was mixed with three old words they already knew. The other group got high-density reinforcement: lots of praise and tokens, but only for the new words. The team flipped the two methods each day so every child tried both.
The kids were school-age and had mild to moderate ID. Sessions lasted a typical class period. The goal was to see which method taught more words and kept them remembered after one day and again after two weeks.
What they found
Interspersal training won. Kids learned new spellings faster and remembered more of them later. The high-density reinforcement group needed more trials to reach the same score. On follow-up tests, the interspersal group kept most of their gains while the other group lost ground.
How this fits with other research
Knutson et al. (2019) flipped this result upside-down. They worked with kids with autism and found the fastest learning happened with zero mastered tasks mixed in—just new material. The difference is the population and the ratio. A et al. used 3:1 old-to-new; Knutson tested 3:1, 1:1, and 0:1. For children with ASD, dropping the mastered items entirely saved time.
Charlop et al. (1992) extends the idea to autism while keeping the interspersal frame. They showed you can give edible reinforcers only on the new-task trials and still see gains, proving the procedure works even when rewards are lean on the old items.
Vollmer et al. (1996) is a conceptual replication: same spelling goal, same ID population, large positive effect, but delivered the lessons on a computer instead of with a teacher. The takeaway—spelling gains hold up across different ways of running the task.
Why it matters
If you serve kids with ID, mix old and new spelling words at about three-to-one. You will spend less teaching time and get stronger recall. Skip the extra tokens; the mix itself seems to keep kids engaged. For children with ASD, check Knutson’s 0:1 ratio first—it may be even faster.
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02At a glance
03Original abstract
This study investigated the effects of interspersing known items during spelling instruction on new words for three mentally retarded students. Following a baseline consisting of the presentation of 10 test words per session, a multielement design was implemented. During interspersal training sessions, previously mastered words were presented alternately with each of 10 test words. During high-density reinforcement sessions, 10 test words were presented and additional reinforcement was provided for task-related behaviors. Throughout all conditions, test words were deleted and replaced after meeting a mastery criterion. Periodic retention tests were administered over mastered words and a cumulative retention test was administered at the end of the experiment. Results showed that high-density reinforcement did facilitate performance over baseline; however, intersperal training was superior to the other conditions in terms of both acquisition rate and short- and long-term retention. In addition, students preferred the interspersal condition when offered a choice.
Journal of applied behavior analysis, 1980 · doi:10.1901/jaba.1980.13-153