Establishing conditional discriminations: concurrent versus isolation-intermix instruction.
Put all comparison stimuli on the table from trial one—concurrent setup slashes teaching time.
01Research in Context
What this study did
Four preschoolers learned conditional discriminations.
The team compared two ways to teach.
Concurrent showed all choices together from the start.
Isolation-intermix taught one pair first, then mixed pairs later.
Both methods used constant or progressive time delay prompts.
An alternating-treatments design flipped the order each day.
What they found
Concurrent instruction won.
Kids reached mastery in fewer trials and less time.
No extra errors happened from the faster pace.
How this fits with other research
Lincoln et al. (1988) saw the same pattern with laundry skills.
Concurrent chaining beat forward chaining for teens with severe handicaps.
The 1988 study is a direct predecessor; it proved the idea works for daily living tasks.
Zhao et al. (2026) extends the story to bilingual tacts.
Simultaneous language presentation again beat sequential steps for kids with autism.
Perez et al. (2015) looks like a contradiction at first.
They found simple-to-complex sequencing worked better than simultaneous blocks for college students forming equivalence classes.
The gap is age and task.
Preschoolers need the full view right away; adults profit from stepped complexity.
Why it matters
Start conditional discrimination programs with all stimuli visible.
You will save trials and minutes without hurting accuracy.
This move is safe for preschoolers and likely for older learners with ID.
Try it next session when you teach new matching, listener, or intraverbal tasks.
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02At a glance
03Original abstract
This paper describes an investigation comparing the effectiveness and efficiency (sessions to criterion, errors to criterion, minutes of instructional time) of concurrent and isolation-intermix instruction in teaching four preschool children to read words found in community and school environments. Two students were taught words using constant time delay and two progressive time delay across the two different conditions. Concurrent instruction consisted of two sessions per day where two words were randomly presented within each session until criterion was reached and a conditional discrimination was established. The isolation-intermix condition involved two sessions per day where each word was taught in separate daily sessions until criterion was reached and a simple discrimination was established (isolation instruction); followed by random presentation of both words within each daily session until the conditional discrimination was acquired (intermix). Concurrent instruction resulted in students learning conditional discriminations in fewer trials and minutes of instructional time. These data suggest that teachers should structure their instruction to teach conditional discriminations from the beginning rather than teaching simple discriminations.
Research in developmental disabilities, 1989 · doi:10.1016/0891-4222(89)90036-x